Update web-ui to beta.4 (#9047 )

* add site data * gofmt * fix embed * fmt Co-authored-by: Raul Jordan <raul@prysmaticlabs.com> (cherry picked from commit 9dc4c49fbd)
Revert "Invert attest-timely flag" (#9044 )
2026-01-11 06:18:05 -05:00 · 2021-06-16 08:44:02 -05:00 · 2021-06-15 18:11:06 -05:00
3234 changed files with 166844 additions and 270849 deletions
--- a/.bazelrc
+++ b/.bazelrc
@@ -21,24 +21,34 @@ run --host_force_python=PY2
 build --sandbox_default_allow_network=false

 # Stamp binaries with git information
-build --workspace_status_command=./hack/workspace_status.sh
+build --workspace_status_command=./scripts/workspace_status.sh
 build --stamp

+# Use mainnet protobufs at runtime
+run --define ssz=mainnet
+test --define ssz=mainnet
+build --define ssz=mainnet
+
 # Prevent PATH changes from rebuilding when switching from IDE to command line.
 build --incompatible_strict_action_env
 test --incompatible_strict_action_env
 run --incompatible_strict_action_env

+# Disable kafka by default, it takes a long time to build...
+build --define kafka_enabled=false
+test --define kafka_enabled=false
+run --define kafka_enabled=false
+
 build --define blst_disabled=false
 test --define blst_disabled=false
 run --define blst_disabled=false

+build:kafka_enabled --define kafka_enabled=true
+build:kafka_enabled --define gotags=kafka_enabled
+
 build:blst_disabled --define blst_disabled=true
 build:blst_disabled --define gotags=blst_disabled

-build:minimal --//proto:network=minimal
-build:minimal --@io_bazel_rules_go//go/config:tags=minimal
-
 # Release flags
 build:release --compilation_mode=opt
 build:release --config=llvm
@@ -62,7 +72,20 @@ build:llvm-asan --config=llvm
 build:llvm-asan --config=asan
 build:llvm-asan --linkopt -fuse-ld=ld.lld

-build:fuzz --@io_bazel_rules_go//go/config:tags=fuzz
+build:fuzz --define=gotags=libfuzzer
+build:fuzz --config=llvm-asan
+build:fuzz --copt=-fsanitize=fuzzer-no-link
+build:fuzz --linkopt=-fsanitize=fuzzer
+build:fuzz --copt=-fno-omit-frame-pointer
+build:fuzz --define=FUZZING_ENGINE=libfuzzer
+build:fuzz --copt=-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+build:fuzz --linkopt -Wl,--no-as-needed
+build:fuzz --define=gc_goopts=-d=libfuzzer,checkptr
+build:fuzz --run_under=//tools:fuzz_wrapper
+build:fuzz --compilation_mode=opt
+build:fuzz --define=blst_disabled=true
+
+test:fuzz --local_test_jobs="HOST_CPUS*.5"

 # Build binary with cgo symbolizer for debugging / profiling.
 build:cgo_symbolizer --config=llvm
@@ -217,6 +240,3 @@ build:remote --remote_local_fallback

 # Ignore GoStdLib with remote caching
 build --modify_execution_info='GoStdlib.*=+no-remote-cache'
-
-# Set bazel gotag
-build --define gotags=bazel
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-5.0.0
+3.7.0
--- a/.buildkite-bazelrc
+++ b/.buildkite-bazelrc
@@ -14,33 +14,32 @@ build:remote-cache --remote_download_minimal
 build:remote-cache --remote_cache=grpc://bazel-remote-cache:9092
 build:remote-cache --experimental_remote_downloader=grpc://bazel-remote-cache:9092
 build:remote-cache --remote_local_fallback
-build:remote-cache --experimental_remote_cache_async
-build:remote-cache --experimental_remote_merkle_tree_cache
-build:remote-cache --experimental_action_cache_store_output_metadata
-build:remote-cache --experimental_remote_cache_compression
 # Enforce stricter environment rules, which eliminates some non-hermetic
 # behavior and therefore improves both the remote cache hit rate and the
 # correctness and repeatability of the build.
 build:remote-cache --incompatible_strict_action_env=true

-build --experimental_use_hermetic_linux_sandbox
-
 # Import workspace options.
 import %workspace%/.bazelrc

-startup --host_jvm_args=-Xmx4g --host_jvm_args=-Xms2g
+startup --host_jvm_args=-Xmx1000m --host_jvm_args=-Xms1000m
+query --repository_cache=/tmp/repositorycache
+query --experimental_repository_cache_hardlinks
+build --repository_cache=/tmp/repositorycache
+build --experimental_repository_cache_hardlinks
 build --experimental_strict_action_env
+build --disk_cache=/tmp/bazelbuilds
+build --experimental_multi_threaded_digest
 build --sandbox_tmpfs_path=/tmp
 build --verbose_failures
 build --announce_rc
 build --show_progress_rate_limit=5
-build --curses=no --color=no
+build --curses=yes --color=no
 build --keep_going
 build --test_output=errors
 build --flaky_test_attempts=5
 # Disabled race detection due to unstable test results under constrained environment build kite
 # build --features=race

-# Better caching
-build:nostamp --nostamp
-build:nostamp --workspace_status_command=./hack/workspace_status_ci.sh
+# Disable flaky test detection for fuzzing.
+test:fuzz --flaky_test_attempts=1
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -6,11 +6,3 @@

 # Anyone on prylabs team can approve dependency updates.
 deps.bzl @prysmaticlabs/core-team
-
-# Radek and Nishant are responsible for changes that can affect the native state feature.
-# See https://www.notion.so/prysmaticlabs/Native-Beacon-State-Redesign-6cc9744b4ec1439bb34fa829b36a35c1
-/beacon-chain/state/fieldtrie/ @rkapka @nisdas
-/beacon-chain/state/v1/ @rkapka @nisdas
-/beacon-chain/state/v2/ @rkapka @nisdas
-/beacon-chain/state/v3/ @rkapka @nisdas
-/beacon-chain/state/state-native/ @rkapka @nisdas
--- a/.github/actions/gomodtidy/entrypoint.sh
+++ b/.github/actions/gomodtidy/entrypoint.sh
@@ -1,13 +1,13 @@
 #!/bin/sh -l
 set -e
-export PATH="$PATH:/usr/local/go/bin"
+export PATH=$PATH:/usr/local/go/bin

-cd "$GITHUB_WORKSPACE"
+cd $GITHUB_WORKSPACE

 cp go.mod go.mod.orig
 cp go.sum go.sum.orig

-go mod tidy -compat=1.17
+go mod tidy

 echo "Checking go.mod and go.sum:"
 checks=0
--- a/.github/workflows/dappnode-release-trigger.yml
+++ b/.github/workflows/dappnode-release-trigger.yml
@@ -0,0 +1,41 @@
+name: Update DAppNodePackages
+
+on:
+  push:
+    tags:
+    - '*'
+
+jobs:
+  dappnode-update-beacon-chain:
+    name: Trigger a beacon-chain release
+    runs-on: ubuntu-latest
+    steps:
+    - name: Get latest tag
+      id: get_tag
+      run: echo ::set-output name=TAG::${GITHUB_REF/refs\/tags\//}
+    - name: Send dispatch event to DAppNodePackage-prysm-beacon-chain
+      env: 
+        DISPATCH_REPO: dappnode/DAppNodePackage-prysm-beacon-chain
+      run: |
+        curl -v -X POST -u "${{ secrets.PAT_GITHUB }}" \
+        -H "Accept: application/vnd.github.everest-preview+json" \
+        -H "Content-Type: application/json" \
+        --data '{"event_type":"new_release", "client_payload": { "tag":"${{ steps.get_tag.outputs.TAG }}"}}' \
+        https://api.github.com/repos/$DISPATCH_REPO/dispatches
+        
+  dappnode-update-validator:
+    name: Trigger a validator release
+    runs-on: ubuntu-latest
+    steps:
+    - name: Get latest tag
+      id: get_tag
+      run: echo ::set-output name=TAG::${GITHUB_REF/refs\/tags\//}
+    - name: Send dispatch event to DAppNodePackage validator repository
+      env: 
+        DISPATCH_REPO: dappnode/DAppNodePackage-prysm-validator
+      run: |
+        curl -v -X POST -u "${{ secrets.PAT_GITHUB }}" \
+        -H "Accept: application/vnd.github.everest-preview+json" \
+        -H "Content-Type: application/json" \
+        --data '{"event_type":"new_release", "client_payload": { "tag":"${{ steps.get_tag.outputs.TAG }}"}}' \
+        https://api.github.com/repos/$DISPATCH_REPO/dispatches
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -7,12 +7,13 @@ on:
    branches: [ '*' ]

 jobs:
-  formatting:
-    name: Formatting
+
+  check:
+    name: Check
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v1

      - name: Go mod tidy checker
        id: gomodtidy
@@ -24,50 +25,6 @@ jobs:
        with:
          path: ./

-      - name: GoImports checker
-        id: goimports
-        uses: Jerome1337/goimports-action@v1.0.2
-        with:
-          goimports-path: ./
-
-  gosec:
-    name: Gosec scan
-    runs-on: ubuntu-latest
-    env:
-      GO111MODULE: on
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Set up Go 1.17
-        uses: actions/setup-go@v3
-        with:
-          go-version: 1.17
-      - name: Run Gosec Security Scanner
-        run: | # https://github.com/securego/gosec/issues/469
-          export PATH=$PATH:$(go env GOPATH)/bin
-          go install github.com/securego/gosec/v2/cmd/gosec@latest
-          gosec -exclude=G307 -exclude-dir=crypto/bls/herumi ./...
-
-  lint:
-    name: Lint
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-
-      - name: Set up Go 1.17
-        uses: actions/setup-go@v3
-        with:
-          go-version: 1.17
-          id: go
-
-      - name: Golangci-lint
-        uses: golangci/golangci-lint-action@v2
-        with:
-          args: --print-issued-lines --sort-results --no-config --timeout=10m --disable-all -E deadcode  -E errcheck -E gosimple --skip-files=validator/web/site_data.go --skip-dirs=proto --go=1.17
-          version: v1.45.2
-          skip-go-installation: true
-
  build:
    name: Build
    runs-on: ubuntu-latest
@@ -75,7 +32,7 @@ jobs:
      - name: Set up Go 1.x
        uses: actions/setup-go@v2
        with:
-          go-version: 1.17
+          go-version: ^1.14
        id: go

      - name: Check out code into the Go module directory
--- a/.gitignore
+++ b/.gitignore
@@ -30,5 +30,9 @@ password.txt
 # Dist files
 dist

+# libfuzzer
+oom-*
+crash-*
+
 # deepsource cli
 bin
--- a/.well-known/security.txt
+++ b/.well-known/security.txt
@@ -5,22 +5,21 @@ Contact: mailto:security@prysmaticlabs.com
 Encryption: openpgp4fpr:0AE0051D647BA3C1A917AF4072E33E4DF1A5036E
 Encryption: openpgp4fpr:CD08DE68C60B82D3EE2A3F7D95452A701810FEDB
 Encryption: openpgp4fpr:317D6E91058F8F3C2303BA7756313E44581297A6
-Encryption: openpgp4fpr:79C59A585E3FD3AFFA00F5C22940A6479DA7C9EC
 Preferred-Languages: en
 Canonical: https://github.com/prysmaticlabs/prysm/tree/master/.well-known/security.txt
 -----BEGIN PGP SIGNATURE-----

-iQIzBAEBCgAdFiEECuAFHWR7o8GpF69AcuM+TfGlA24FAmGOfiYACgkQcuM+TfGl
-A24YwRAAiQk3w6yzqSEggrOlNoNn04iu/rWZdn5ihkQgzACXy8XH2D1gdKLChE/X
-7e5bUtgE2aCuHryQjwoKxqZakviBJFstVmHgF64rXv2zKhpqA30Mj4fI+T3zn8I+
-+FpFV0TTsxNLDx+AcR1eQ1nSayO7ImUDIfOQNDDnSZZy42Bc+F+QIGKB3aH/8bpG
-kT+bDTZrXvX+TE1gZTbAtZG8sH8g/zadoWEHIhfXUuYb0kTz+DRzAxoqU4j4Z4ee
-1zSfFAgfJwxJP4kWD7s4xkE1sBbCgGBeD6cW/C2lbcfIei+XSizLpHW3jD9dNqh4
-fLkmEspSa/LV/iXFq8nFzu/GLww4q+sQZDzzDKZyws54CrATinRitZMhzoIL0bTn
-yFZVOGHosFAMEVZ36dl1Aw2+B2W6tr2CVr9c5zfV+kup5/KZH1EmT5nYY/zFwfg2
-jYCFB5wmYeiyWZvuprgJXRArgVZLZaJxwWazlPVk4i/4vPvRgvfHqOwHCBe8DXy0
-VHPhpewwb/ECYek1KoaNQflgR8iH2GMHkC5RjhGDAt1S0AQDtite5m4ZYt1kvO9E
-k/znkv89dduhL9CKDvZvnI+DICwsTrf//4KJ8PM/qaPAJa4GvtiUU/eS/jKBivtv
-OP5dZQtX6KPc9ewqqZgn622uHSezoBidgeTkdZsJ6tw2eIu0lsY=
-=V7L0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+=uW+X
 -----END PGP SIGNATURE-----
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -3,7 +3,7 @@ load("@com_github_atlassian_bazel_tools//gometalinter:def.bzl", "gometalinter")
 load("@com_github_atlassian_bazel_tools//goimports:def.bzl", "goimports")
 load("@io_kubernetes_build//defs:run_in_workspace.bzl", "workspace_binary")
 load("@io_bazel_rules_go//go:def.bzl", "nogo")
-load("@vaticle_bazel_distribution//common:rules.bzl", "assemble_targz", "assemble_versioned")
+load("@graknlabs_bazel_distribution//common:rules.bzl", "assemble_targz", "assemble_versioned")
 load("@bazel_skylib//rules:common_settings.bzl", "string_setting")

 prefix = "github.com/prysmaticlabs/prysm"
@@ -14,10 +14,7 @@ exports_files([

 # gazelle:prefix github.com/prysmaticlabs/prysm
 # gazelle:map_kind go_library go_library @prysm//tools/go:def.bzl
-# gazelle:map_kind go_test go_test @prysm//tools/go:def.bzl
 # gazelle:map_kind go_repository go_repository @prysm//tools/go:def.bzl
-# gazelle:build_tags bazel
-# gazelle:exclude tools/analyzers/**/testdata/**
 gazelle(
    name = "gazelle",
    prefix = prefix,
@@ -88,52 +85,50 @@ nogo(
    config = "nogo_config.json",
    visibility = ["//visibility:public"],
    deps = [
-        "@org_golang_x_tools//go/analysis/passes/unsafeptr:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/unreachable:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/unmarshal:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/tests:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/structtag:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/stdmethods:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/shift:go_default_library",
-        # "@org_golang_x_tools//go/analysis/passes/shadow:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/printf:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/pkgfact:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/nilness:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/nilfunc:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/loopclosure:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/httpresponse:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/findcall:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/deepequalerrors:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/ctrlflow:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/copylock:go_default_library",
-        #  "@org_golang_x_tools//go/analysis/passes/cgocall:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/buildtag:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/buildssa:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/bools:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/atomicalign:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/atomic:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/assign:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/inspect:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/asmdecl:go_default_library",
-        "//tools/analyzers/maligned:go_default_library",
-        "//tools/analyzers/cryptorand:go_default_library",
-        "//tools/analyzers/errcheck:go_default_library",
-        "//tools/analyzers/featureconfig:go_default_library",
-        "//tools/analyzers/comparesame:go_default_library",
-        "//tools/analyzers/shadowpredecl:go_default_library",
-        "//tools/analyzers/nop:go_default_library",
-        "//tools/analyzers/slicedirect:go_default_library",
-        "//tools/analyzers/interfacechecker:go_default_library",
-        "//tools/analyzers/ineffassign:go_default_library",
-        "//tools/analyzers/properpermissions:go_default_library",
-        "//tools/analyzers/recursivelock:go_default_library",
-        "//tools/analyzers/uintcast:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/unsafeptr:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/unreachable:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/unmarshal:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/tests:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/structtag:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/stdmethods:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/shift:go_tool_library",
+        # "@org_golang_x_tools//go/analysis/passes/shadow:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/printf:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/pkgfact:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/nilness:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/nilfunc:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/loopclosure:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/httpresponse:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/findcall:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/deepequalerrors:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/ctrlflow:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/copylock:go_tool_library",
+        #  "@org_golang_x_tools//go/analysis/passes/cgocall:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/buildtag:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/buildssa:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/bools:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/atomicalign:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/atomic:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/assign:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/inspect:go_tool_library",
+        "@org_golang_x_tools//go/analysis/passes/asmdecl:go_tool_library",
+        "//tools/analyzers/maligned:go_tool_library",
+        "//tools/analyzers/cryptorand:go_tool_library",
+        "//tools/analyzers/errcheck:go_tool_library",
+        "//tools/analyzers/featureconfig:go_tool_library",
+        "//tools/analyzers/comparesame:go_tool_library",
+        "//tools/analyzers/shadowpredecl:go_tool_library",
+        "//tools/analyzers/nop:go_tool_library",
+        "//tools/analyzers/slicedirect:go_tool_library",
+        "//tools/analyzers/interfacechecker:go_tool_library",
+        "//tools/analyzers/ineffassign:go_tool_library",
+        "//tools/analyzers/properpermissions:go_tool_library",
    ] + select({
        # nogo checks that fail with coverage enabled.
        ":coverage_enabled": [],
        "//conditions:default": [
-            "@org_golang_x_tools//go/analysis/passes/lostcancel:go_default_library",
-            "@org_golang_x_tools//go/analysis/passes/composite:go_default_library",
+            "@org_golang_x_tools//go/analysis/passes/lostcancel:go_tool_library",
+            "@org_golang_x_tools//go/analysis/passes/composite:go_tool_library",
        ],
    }),
 )
@@ -148,8 +143,17 @@ common_files = {
    "//:README.md": "README.md",
 }

-sh_binary(
-    name = "prysm_sh",
-    srcs = ["prysm.sh"],
-    visibility = ["//visibility:public"],
+toolchain(
+    name = "built_cmake_toolchain",
+    toolchain = "@rules_foreign_cc//tools/build_defs/native_tools:built_cmake",
+    toolchain_type = "@rules_foreign_cc//tools/build_defs:cmake_toolchain",
+)
+
+string_setting(
+    name = "gotags",
+    build_setting_default = "",
+    values = [
+        "",
+        "libfuzzer",
+    ],
 )
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -175,7 +175,7 @@ We consider two types of contributions to our repo and categorize them as follow

 ### Part-Time Contributors

-Anyone can become a part-time contributor and help out on implementing Ethereum consensus. The responsibilities of a part-time contributor include:
+Anyone can become a part-time contributor and help out on implementing eth2. The responsibilities of a part-time contributor include:

 -   Engaging in Gitter conversations, asking the questions on how to begin contributing to the project
 -   Opening up github issues to express interest in code to implement
@@ -190,7 +190,7 @@ Anyone can become a part-time contributor and help out on implementing Ethereum

 Core contributors are remote contractors of Prysmatic Labs, LLC. and are considered critical team members of our organization. Core devs have all of the responsibilities of part-time contributors plus the majority of the following:

-   Stay up to date on the latest beacon chain specification
+-   Stay up to date on the latest beacon chain sepcification
 -   Monitor github issues and PR’s to make sure owner, labels, descriptions are correct
 -   Formulate independent ideas, suggest new work to do, point out improvements to existing approaches
 -   Participate in code review, ensure code quality is excellent, and have ensure high code coverage
--- a/DEPENDENCIES.md
+++ b/DEPENDENCIES.md
@@ -33,8 +33,8 @@ generates SSZ marshal related code based on defined data structures. These gener
 also be updated and checked in as frequently.

 ```bash
-./hack/update-go-pbs.sh
-./hack/update-go-ssz.sh
+./scripts/update-go-pbs.sh
+./scripts/update-go-ssz.sh
 ```

 *Recommendation: Use go build only for local development and use bazel build for production.*
--- a/INTEROP.md
+++ b/INTEROP.md
@@ -1,6 +1,6 @@
 # Prysm Client Interoperability Guide

-This README details how to setup Prysm for interop testing for usage with other Ethereum consensus clients.
+This README details how to setup Prysm for interop testing for usage with other Ethereum 2.0 clients.

 ## Installation & Setup

--- a/README.md
+++ b/README.md
@@ -1,11 +1,11 @@
-# Prysm: An Ethereum Consensus Implementation Written in Go
+# Prysm: An Ethereum 2.0 Implementation Written in Go

 [![Build status](https://badge.buildkite.com/b555891daf3614bae4284dcf365b2340cefc0089839526f096.svg?branch=master)](https://buildkite.com/prysmatic-labs/prysm)
 [![Go Report Card](https://goreportcard.com/badge/github.com/prysmaticlabs/prysm)](https://goreportcard.com/report/github.com/prysmaticlabs/prysm)
-[![Consensus_Spec_Version 1.1.8](https://img.shields.io/badge/Consensus%20Spec%20Version-v1.1.8-blue.svg)](https://github.com/ethereum/consensus-specs/tree/v1.1.8)
+[![ETH2.0_Spec_Version 1.0.0](https://img.shields.io/badge/ETH2.0%20Spec%20Version-v1.0.0-blue.svg)](https://github.com/ethereum/eth2.0-specs/tree/v1.0.0)
 [![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/CTYGPUJ)

-This is the core repository for Prysm, a [Golang](https://golang.org/) implementation of the [Ethereum Consensus](https://ethereum.org/en/eth2/) specification, developed by [Prysmatic Labs](https://prysmaticlabs.com). See the [Changelog](https://github.com/prysmaticlabs/prysm/releases) for details of the latest releases and upcoming breaking changes.
+This is the core repository for Prysm, a [Golang](https://golang.org/) implementation of the [Ethereum 2.0](https://ethereum.org/en/eth2/) specification, developed by [Prysmatic Labs](https://prysmaticlabs.com). See the [Changelog](https://github.com/prysmaticlabs/prysm/releases) for details of the latest releases and upcoming breaking changes.

 ### Getting Started

--- a/SECURITY.md
+++ b/SECURITY.md
@@ -1,11 +0,0 @@
-# Security Policy
-
-## Supported Versions
-
-[Releases](https://github.com/prysmaticlabs/prysm/releases/) contains all available releases. We recommend using the [most recently released version](https://github.com/prysmaticlabs/prysm/releases/latest).
-
-## Reporting a Vulnerability
-
-Please see our signed [security.txt](https://github.com/prysmaticlabs/prysm/blob/develop/.well-known/security.txt) for preferred encryption and reporting destination.
-
-**Please do not file a public ticket** mentioning the vulnerability, as doing so could increase the likelihood of the vulnerability being used before a fix has been created, released and installed on the network.
--- a/TERMS_OF_SERVICE.md
+++ b/TERMS_OF_SERVICE.md
@@ -5,7 +5,7 @@ Effective as of Oct 14, 2020
 By downloading, accessing or using the Prysm implementation (“Prysm”), you (referenced herein as “you” or the “user”) certify that you have read and agreed to the terms and conditions below (the “Terms”) which form a binding contract between you and Prysmatic Labs (referenced herein as “we” or “us”). If you do not agree to the Terms, do not download or use Prysm.

 ### About Prysm
-Prysm is a client implementation for Ethereum consensus protocol for a proof-of-stake blockchain. To participate in the network, a user must send ETH from the Eth1.0 chain into a validator deposit contract, which will queue in the user as a validator in the system. Validators participate in proposing and voting on blocks in the protocol, and the network applies rewards/penalties based on their behavior. A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the official documentation portal, however, we do not warrant the accuracy, completeness or usefulness of this documentation. Any reliance you place on such information is strictly at your own risk.
+Prysm is a client implementation for Ethereum 2.0 Phase 0 protocol for a proof-of-stake blockchain. To participate in the network, a user must send ETH from the Eth1.0 chain into a validator deposit contract, which will queue in the user as a validator in the system. Validators participate in proposing and voting on blocks in the protocol, and the network applies rewards/penalties based on their behavior. A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the official documentation portal, however, we do not warrant the accuracy, completeness or usefulness of this documentation. Any reliance you place on such information is strictly at your own risk.

 ### Licensing Terms
 Prysm is a fully open-source software program licensed pursuant to the GNU General Public License v3.0.
@@ -13,7 +13,7 @@ Prysm is a fully open-source software program licensed pursuant to the GNU Gener
 The Prysmatic Labs name, the term “Prysm” and all related names, logos, product and service names, designs and slogans are trademarks of Prysmatic Labs or its affiliates and/or licensors. You must not use such marks without our prior written permission.

 ### Risks of Operating Prysm
-The use of Prysm and acting as a validator on the Ethereum network can lead to loss of money. Ethereum is still an experimental system and ETH remains a risky investment. You alone are responsible for your actions on Prysm including the security of your ETH and meeting any applicable minimum system requirements.
+The use of Prysm and acting as a validator on the Ethereum 2.0 network can lead to loss of money. Ethereum is still an experimental system and ETH remains a risky investment. You alone are responsible for your actions on Prysm including the security of your ETH and meeting any applicable minimum system requirements.

 Use of Prysm and the ability to receive rewards or penalties may be affected at any time by mistakes made by the user or other users, software problems such as bugs, errors, incorrectly constructed transactions, unsafe cryptographic libraries or malware affecting the network, technical failures in the hardware of a user, security problems experienced by a user and/or actions or inactions of third parties and/or events experienced by third parties, among other risks. We cannot and do not guarantee that any user of Prysm will make money, that the Prysm network will operate in accordance with the documentation or that transactions will be effective or secure.

--- a/252
+++ b/252
@@ -60,10 +60,10 @@ bazel_skylib_workspace()

 http_archive(
    name = "bazel_gazelle",
-    sha256 = "de69a09dc70417580aabf20a28619bb3ef60d038470c7cf8442fafcf627c21cb",
+    sha256 = "62ca106be173579c0a167deb23358fdfe71ffa1e4cfdddf5582af26520f1c66f",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.24.0/bazel-gazelle-v0.24.0.tar.gz",
-        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.24.0/bazel-gazelle-v0.24.0.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.23.0/bazel-gazelle-v0.23.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.23.0/bazel-gazelle-v0.23.0.tar.gz",
    ],
 )

@@ -76,22 +76,23 @@ http_archive(

 http_archive(
    name = "io_bazel_rules_docker",
-    sha256 = "1f4e59843b61981a96835dc4ac377ad4da9f8c334ebe5e0bb3f58f80c09735f4",
-    strip_prefix = "rules_docker-0.19.0",
-    urls = ["https://github.com/bazelbuild/rules_docker/releases/download/v0.19.0/rules_docker-v0.19.0.tar.gz"],
+    sha256 = "59d5b42ac315e7eadffa944e86e90c2990110a1c8075f1cd145f487e999d22b3",
+    strip_prefix = "rules_docker-0.17.0",
+    urls = ["https://github.com/bazelbuild/rules_docker/releases/download/v0.17.0/rules_docker-v0.17.0.tar.gz"],
 )

 http_archive(
    name = "io_bazel_rules_go",
    patch_args = ["-p1"],
    patches = [
-        # Expose internals of go_test for custom build transitions.
-        "//third_party:io_bazel_rules_go_test.patch",
+        # Required until https://github.com/bazelbuild/rules_go/pull/2450 merges otherwise nilness
+        # nogo check fails for certain third_party dependencies.
+        "//third_party:io_bazel_rules_go.patch",
    ],
-    sha256 = "2b1641428dff9018f9e85c0384f03ec6c10660d935b750e3fa1492a281a53b0f",
+    sha256 = "7c10271940c6bce577d51a075ae77728964db285dac0a46614a7934dc34303e6",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.29.0/rules_go-v0.29.0.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.29.0/rules_go-v0.29.0.zip",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.26.0/rules_go-v0.26.0.tar.gz",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.26.0/rules_go-v0.26.0.tar.gz",
    ],
 )

@@ -117,6 +118,13 @@ http_archive(
    urls = ["https://github.com/fuzzitdev/fuzzit/releases/download/v2.4.76/fuzzit_Linux_x86_64.zip"],
 )

+git_repository(
+    name = "graknlabs_bazel_distribution",
+    commit = "962f3a7e56942430c0ec120c24f9e9f2a9c2ce1a",
+    remote = "https://github.com/graknlabs/bazel-distribution",
+    shallow_since = "1569509514 +0300",
+)
+
 load(
    "@io_bazel_rules_docker//repositories:repositories.bzl",
    container_repositories = "repositories",
@@ -129,34 +137,6 @@ load(
    "container_pull",
 )

-container_pull(
-    name = "cc_image_base",
-    digest = "sha256:2c4bb6b7236db0a55ec54ba8845e4031f5db2be957ac61867872bf42e56c4deb",
-    registry = "gcr.io",
-    repository = "distroless/cc",
-)
-
-container_pull(
-    name = "cc_debug_image_base",
-    digest = "sha256:3680c61e81f68fc00bfb5e1ec65e8e678aaafa7c5f056bc2681c29527ebbb30c",
-    registry = "gcr.io",
-    repository = "distroless/cc",
-)
-
-container_pull(
-    name = "go_image_base",
-    digest = "sha256:ba7a315f86771332e76fa9c3d423ecfdbb8265879c6f1c264d6fff7d4fa460a4",
-    registry = "gcr.io",
-    repository = "distroless/base",
-)
-
-container_pull(
-    name = "go_debug_image_base",
-    digest = "sha256:efd8711717d9e9b5d0dbb20ea10876dab0609c923bc05321b912f9239090ca80",
-    registry = "gcr.io",
-    repository = "distroless/base",
-)
-
 container_pull(
    name = "alpine_cc_linux_amd64",
    digest = "sha256:752aa0c9a88461ffc50c5267bb7497ef03a303e38b2c8f7f2ded9bebe5f1f00e",
@@ -176,10 +156,40 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()

 go_register_toolchains(
-    go_version = "1.17.6",
+    go_version = "1.16.4",
    nogo = "@//:nogo",
 )

+load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies")
+
+gazelle_dependencies()
+
+load("@io_bazel_rules_go//extras:embed_data_deps.bzl", "go_embed_data_dependencies")
+
+go_embed_data_dependencies()
+
+load("@com_github_atlassian_bazel_tools//gometalinter:deps.bzl", "gometalinter_dependencies")
+
+gometalinter_dependencies()
+
+load(
+    "@io_bazel_rules_docker//go:image.bzl",
+    _go_image_repos = "repositories",
+)
+
+# Golang images
+# This is using gcr.io/distroless/base
+_go_image_repos()
+
+# CC images
+# This is using gcr.io/distroless/base
+load(
+    "@io_bazel_rules_docker//cc:image.bzl",
+    _cc_image_repos = "repositories",
+)
+
+_cc_image_repos()
+
 http_archive(
    name = "prysm_testnet_site",
    build_file_content = """
@@ -212,15 +222,11 @@ filegroup(
 )
    """,
    sha256 = "91434d5fd5e1c6eb7b0174fed2afe25e09bddf00e1e4c431db931b2cee4e7773",
-    url = "https://github.com/eth-clients/slashing-protection-interchange-tests/archive/b8413ca42dc92308019d0d4db52c87e9e125c4e9.tar.gz",
+    url = "https://github.com/eth2-clients/slashing-protection-interchange-tests/archive/b8413ca42dc92308019d0d4db52c87e9e125c4e9.tar.gz",
 )

-consensus_spec_version = "v1.1.10"
-
-bls_test_version = "v0.1.1"
-
 http_archive(
-    name = "consensus_spec_tests_general",
+    name = "eth2_spec_tests_general",
    build_file_content = """
 filegroup(
    name = "test_data",
@@ -231,12 +237,12 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "28043009cc2f6fc9804e73c8c1fc2cb27062f1591e6884f3015ae1dd7a276883",
-    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
+    sha256 = "deacc076365c727d653ac064894ecf0d1b0a675d86704dc8de271259f6a7314b",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/general.tar.gz",
 )

 http_archive(
-    name = "consensus_spec_tests_minimal",
+    name = "eth2_spec_tests_minimal",
    build_file_content = """
 filegroup(
    name = "test_data",
@@ -247,12 +253,12 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "bc1a283ca068f310f04d70c4f6a8eaa0b8f7e9318073a8bdc2ee233111b4e339",
-    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
+    sha256 = "6e9886af3d2f024e563249d70388129e28e3e92f742f289238ed9b7ec7a7f930",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/minimal.tar.gz",
 )

 http_archive(
-    name = "consensus_spec_tests_mainnet",
+    name = "eth2_spec_tests_mainnet",
    build_file_content = """
 filegroup(
    name = "test_data",
@@ -263,64 +269,21 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "bbabb482c229ff9d4e2c7b77c992edb452f9d0af7c6d8dd4f922f06a7b101e81",
-    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
-)
-
-http_archive(
-    name = "consensus_spec",
-    build_file_content = """
-filegroup(
-    name = "spec_data",
-    srcs = glob([
-        "**/*.yaml",
-    ]),
-    visibility = ["//visibility:public"],
-)
-    """,
-    sha256 = "408a5524548ad3fcf387f65ac7ec52781d9ee899499720bb12451b48a15818d4",
-    strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
-    url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
-)
-
-http_archive(
-    name = "bls_spec_tests",
-    build_file_content = """
-filegroup(
-    name = "test_data",
-    srcs = glob([
-        "**/*.yaml",
-    ]),
-    visibility = ["//visibility:public"],
-)
-    """,
-    sha256 = "93c7d006e7c5b882cbd11dc9ec6c5d0e07f4a8c6b27a32f964eb17cf2db9763a",
-    url = "https://github.com/ethereum/bls12-381-tests/releases/download/%s/bls_tests_yaml.tar.gz" % bls_test_version,
-)
-
-http_archive(
-    name = "eth2_networks",
-    build_file_content = """
-filegroup(
-    name = "configs",
-    srcs = glob([
-        "shared/**/config.yaml",
-    ]),
-    visibility = ["//visibility:public"],
-)
-    """,
-    sha256 = "4e8a18b21d056c4032605621b1a6632198eabab57cb90c61e273f344c287f1b2",
-    strip_prefix = "eth2-networks-791a5369c5981e829698b17fbcdcdacbdaba97c8",
-    url = "https://github.com/eth-clients/eth2-networks/archive/791a5369c5981e829698b17fbcdcdacbdaba97c8.tar.gz",
+    sha256 = "a7b3d0ffc02a567250f424d69b2474fdc9477cd56eada60af7474560b46a8527",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/mainnet.tar.gz",
 )

 http_archive(
    name = "com_github_bazelbuild_buildtools",
-    sha256 = "7a182df18df1debabd9e36ae07c8edfa1378b8424a04561b674d933b965372b3",
-    strip_prefix = "buildtools-f2aed9ee205d62d45c55cfabbfd26342f8526862",
-    url = "https://github.com/bazelbuild/buildtools/archive/f2aed9ee205d62d45c55cfabbfd26342f8526862.zip",
+    sha256 = "b5d7dbc6832f11b6468328a376de05959a1a9e4e9f5622499d3bab509c26b46a",
+    strip_prefix = "buildtools-bf564b4925ab5876a3f64d8b90fab7f769013d42",
+    url = "https://github.com/bazelbuild/buildtools/archive/bf564b4925ab5876a3f64d8b90fab7f769013d42.zip",
 )

+load("@com_github_bazelbuild_buildtools//buildifier:deps.bzl", "buildifier_dependencies")
+
+buildifier_dependencies()
+
 git_repository(
    name = "com_google_protobuf",
    commit = "436bd7880e458532901c58f4d9d1ea23fa7edd52",
@@ -328,9 +291,44 @@ git_repository(
    shallow_since = "1617835118 -0700",
 )

+load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
+
+protobuf_deps()
+
 # Group the sources of the library so that CMake rule have access to it
 all_content = """filegroup(name = "all", srcs = glob(["**"]), visibility = ["//visibility:public"])"""

+http_archive(
+    name = "rules_foreign_cc",
+    sha256 = "b85ce66a3410f7370d1a9a61dfe3a29c7532b7637caeb2877d8d0dfd41d77abb",
+    strip_prefix = "rules_foreign_cc-3515b20a2417c4dd51c8a4a8cac1f6ecf3c6d934",
+    url = "https://github.com/bazelbuild/rules_foreign_cc/archive/3515b20a2417c4dd51c8a4a8cac1f6ecf3c6d934.zip",
+)
+
+load("@rules_foreign_cc//:workspace_definitions.bzl", "rules_foreign_cc_dependencies")
+
+rules_foreign_cc_dependencies([
+    "@prysm//:built_cmake_toolchain",
+])
+
+http_archive(
+    name = "librdkafka",
+    build_file_content = all_content,
+    sha256 = "3b99a36c082a67ef6295eabd4fb3e32ab0bff7c6b0d397d6352697335f4e57eb",
+    strip_prefix = "librdkafka-1.4.2",
+    urls = ["https://github.com/edenhill/librdkafka/archive/v1.4.2.tar.gz"],
+)
+
+http_archive(
+    name = "sigp_beacon_fuzz_corpora",
+    build_file = "//third_party:beacon-fuzz/corpora.BUILD",
+    sha256 = "42993d0901a316afda45b4ba6d53c7c21f30c551dcec290a4ca131c24453d1ef",
+    strip_prefix = "beacon-fuzz-corpora-bac24ad78d45cc3664c0172241feac969c1ac29b",
+    urls = [
+        "https://github.com/sigp/beacon-fuzz-corpora/archive/bac24ad78d45cc3664c0172241feac969c1ac29b.tar.gz",
+    ],
+)
+
 # External dependencies

 http_archive(
@@ -342,9 +340,9 @@ filegroup(
    visibility = ["//visibility:public"],
 )
 """,
-    sha256 = "4797a7e594a5b1f4c1c8080701613f3ee451b01ec0861499ea7d9b60877a6b23",
+    sha256 = "54ce527b83d092da01127f2e3816f4d5cfbab69354caba8537f1ea55889b6d7c",
    urls = [
-        "https://github.com/prysmaticlabs/prysm-web-ui/releases/download/v1.0.3/prysm-web-ui.tar.gz",
+        "https://github.com/prysmaticlabs/prysm-web-ui/releases/download/v1.0.0-beta.4/prysm-web-ui.tar.gz",
    ],
 )

@@ -357,46 +355,8 @@ load("@prysm//third_party/herumi:herumi.bzl", "bls_dependencies")

 bls_dependencies()

-load("@prysm//testing/endtoend:deps.bzl", "e2e_deps")
+load("@com_github_ethereum_go_ethereum//:deps.bzl", "geth_dependencies")

-e2e_deps()
-
-load(
-    "@io_bazel_rules_docker//go:image.bzl",
-    _go_image_repos = "repositories",
-)
-
-# Golang images
-# This is using gcr.io/distroless/base
-_go_image_repos()
-
-# CC images
-# This is using gcr.io/distroless/base
-load(
-    "@io_bazel_rules_docker//cc:image.bzl",
-    _cc_image_repos = "repositories",
-)
-
-_cc_image_repos()
-
-load("@io_bazel_rules_go//extras:embed_data_deps.bzl", "go_embed_data_dependencies")
-
-go_embed_data_dependencies()
-
-load("@com_github_atlassian_bazel_tools//gometalinter:deps.bzl", "gometalinter_dependencies")
-
-gometalinter_dependencies()
-
-load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies")
-
-gazelle_dependencies()
-
-load("@com_github_bazelbuild_buildtools//buildifier:deps.bzl", "buildifier_dependencies")
-
-buildifier_dependencies()
-
-load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
-
-protobuf_deps()
+geth_dependencies()

 # Do NOT add new go dependencies here! Refer to DEPENDENCIES.md!
--- a/api/client/beacon/BUILD.bazel
+++ b/api/client/beacon/BUILD.bazel
@@ -1,54 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "checkpoint.go",
-        "client.go",
-        "doc.go",
-        "errors.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/api/client/beacon",
-    visibility = ["//visibility:public"],
-    deps = [
-        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/rpc/apimiddleware:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//encoding/ssz/detect:go_default_library",
-        "//io/file:go_default_library",
-        "//network/forks:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//proto/prysm/v1alpha1/block:go_default_library",
-        "//runtime/version:go_default_library",
-        "//time/slots:go_default_library",
-        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@org_golang_x_mod//semver:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = [
-        "checkpoint_test.go",
-        "client_test.go",
-    ],
-    embed = [":go_default_library"],
-    deps = [
-        "//beacon-chain/state:go_default_library",
-        "//config/params:go_default_library",
-        "//encoding/ssz/detect:go_default_library",
-        "//network/forks:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//proto/prysm/v1alpha1/wrapper:go_default_library",
-        "//runtime/version:go_default_library",
-        "//testing/require:go_default_library",
-        "//testing/util:go_default_library",
-        "//time/slots:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
-    ],
-)
--- a/api/client/beacon/checkpoint.go
+++ b/api/client/beacon/checkpoint.go
@@ -1,262 +0,0 @@
-package beacon
-
-import (
-	"context"
-	"fmt"
-	"path"
-
-	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/encoding/ssz/detect"
-	"github.com/prysmaticlabs/prysm/io/file"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/runtime/version"
-	"github.com/prysmaticlabs/prysm/time/slots"
-	log "github.com/sirupsen/logrus"
-	"golang.org/x/mod/semver"
-)
-
-// OriginData represents the BeaconState and SignedBeaconBlock necessary to start an empty Beacon Node
-// using Checkpoint Sync.
-type OriginData struct {
-	wsd *WeakSubjectivityData
-	sb  []byte
-	bb  []byte
-	st  state.BeaconState
-	b   block.SignedBeaconBlock
-	cf  *detect.VersionedUnmarshaler
-}
-
-// CheckpointString returns the standard string representation of a Checkpoint for the block root and epoch for the
-// SignedBeaconBlock value found by DownloadOriginData.
-// The format is a a hex-encoded block root, followed by the epoch of the block, separated by a colon. For example:
-// "0x1c35540cac127315fabb6bf29181f2ae0de1a3fc909d2e76ba771e61312cc49a:74888"
-func (od *OriginData) CheckpointString() string {
-	return fmt.Sprintf("%#x:%d", od.wsd.BlockRoot, od.wsd.Epoch)
-}
-
-// SaveBlock saves the downloaded block to a unique file in the given path.
-// For readability and collision avoidance, the file name includes: type, config name, slot and root
-func (od *OriginData) SaveBlock(dir string) (string, error) {
-	blockPath := path.Join(dir, fname("state", od.cf, od.st.Slot(), od.wsd.BlockRoot))
-	return blockPath, file.WriteFile(blockPath, od.sb)
-}
-
-// SaveState saves the downloaded state to a unique file in the given path.
-// For readability and collision avoidance, the file name includes: type, config name, slot and root
-func (od *OriginData) SaveState(dir string) (string, error) {
-	statePath := path.Join(dir, fname("state", od.cf, od.st.Slot(), od.wsd.StateRoot))
-	return statePath, file.WriteFile(statePath, od.sb)
-}
-
-// StateBytes returns the ssz-encoded bytes of the downloaded BeaconState value.
-func (od *OriginData) StateBytes() []byte {
-	return od.sb
-}
-
-// BlockBytes returns the ssz-encoded bytes of the downloaded SignedBeaconBlock value.
-func (od *OriginData) BlockBytes() []byte {
-	return od.bb
-}
-
-func fname(prefix string, cf *detect.VersionedUnmarshaler, slot types.Slot, root [32]byte) string {
-	return fmt.Sprintf("%s_%s_%s_%d-%#x.ssz", prefix, cf.Config.ConfigName, version.String(cf.Fork), slot, root)
-}
-
-// this method downloads the head state, which can be used to find the correct chain config
-// and use prysm's helper methods to compute the latest weak subjectivity epoch.
-func getWeakSubjectivityEpochFromHead(ctx context.Context, client *Client) (types.Epoch, error) {
-	headBytes, err := client.GetState(ctx, IdHead)
-	if err != nil {
-		return 0, err
-	}
-	cf, err := detect.FromState(headBytes)
-	if err != nil {
-		return 0, errors.Wrap(err, "error detecting chain config for beacon state")
-	}
-	log.Printf("detected supported config in remote head state, name=%s, fork=%s", cf.Config.ConfigName, version.String(cf.Fork))
-	headState, err := cf.UnmarshalBeaconState(headBytes)
-	if err != nil {
-		return 0, errors.Wrap(err, "error unmarshaling state to correct version")
-	}
-
-	epoch, err := helpers.LatestWeakSubjectivityEpoch(ctx, headState, cf.Config)
-	if err != nil {
-		return 0, errors.Wrap(err, "error computing the weak subjectivity epoch from head state")
-	}
-
-	log.Printf("(computed client-side) weak subjectivity epoch = %d", epoch)
-	return epoch, nil
-}
-
-const (
-	prysmMinimumVersion     = "v2.0.7"
-	prysmImplementationName = "Prysm"
-)
-
-// ErrUnsupportedPrysmCheckpointVersion indicates remote beacon node can't be used for checkpoint retrieval.
-var ErrUnsupportedPrysmCheckpointVersion = errors.New("node does not meet minimum version requirements for checkpoint retrieval")
-
-// for older endpoints or clients that do not support the weak_subjectivity api method
-// we gather the necessary data for a checkpoint sync by:
-// - inspecting the remote server's head state and computing the weak subjectivity epoch locally
-// - requesting the state at the first slot of the epoch
-// - using hash_tree_root(state.latest_block_header) to compute the block the state integrates
-// - requesting that block by its root
-func downloadBackwardsCompatible(ctx context.Context, client *Client) (*OriginData, error) {
-	log.Print("falling back to generic checkpoint derivation, weak_subjectivity API not supported by server")
-	nv, err := client.GetNodeVersion(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to proceed with fallback method without confirming node version")
-	}
-	if nv.implementation == prysmImplementationName && semver.Compare(nv.semver, prysmMinimumVersion) < 0 {
-		return nil, errors.Wrapf(ErrUnsupportedPrysmCheckpointVersion, "%s < minimum (%s)", nv.semver, prysmMinimumVersion)
-	}
-	epoch, err := getWeakSubjectivityEpochFromHead(ctx, client)
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing weak subjectivity epoch via head state inspection")
-	}
-
-	// use first slot of the epoch for the state slot
-	slot, err := slots.EpochStart(epoch)
-	if err != nil {
-		return nil, errors.Wrapf(err, "error computing first slot of epoch=%d", epoch)
-	}
-
-	log.Printf("requesting checkpoint state at slot %d", slot)
-	// get the state at the first slot of the epoch
-	stateBytes, err := client.GetState(ctx, IdFromSlot(slot))
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to request state by slot from api, slot=%d", slot)
-	}
-
-	// ConfigFork is used to unmarshal the BeaconState so we can read the block root in latest_block_header
-	cf, err := detect.FromState(stateBytes)
-	if err != nil {
-		return nil, errors.Wrap(err, "error detecting chain config for beacon state")
-	}
-	log.Printf("detected supported config in checkpoint state, name=%s, fork=%s", cf.Config.ConfigName, version.String(cf.Fork))
-
-	st, err := cf.UnmarshalBeaconState(stateBytes)
-	if err != nil {
-		return nil, errors.Wrap(err, "error using detected config fork to unmarshal state bytes")
-	}
-
-	// compute state and block roots
-	stateRoot, err := st.HashTreeRoot(ctx)
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root of state")
-	}
-
-	header := st.LatestBlockHeader()
-	header.StateRoot = stateRoot[:]
-	computedBlockRoot, err := header.HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error while computing block root using state data")
-	}
-
-	blockBytes, err := client.GetBlock(ctx, IdFromRoot(computedBlockRoot))
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting block by root = %d", computedBlockRoot)
-	}
-	block, err := cf.UnmarshalBeaconBlock(blockBytes)
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to unmarshal block to a supported type using the detected fork schedule")
-	}
-	blockRoot, err := block.Block().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root for block obtained via root")
-	}
-
-	log.Printf("BeaconState slot=%d, Block slot=%d", st.Slot(), block.Block().Slot())
-	log.Printf("BeaconState htr=%#xd, Block state_root=%#x", stateRoot, block.Block().StateRoot())
-	log.Printf("BeaconBlock root computed from state=%#x, Block htr=%#x", computedBlockRoot, blockRoot)
-
-	return &OriginData{
-		wsd: &WeakSubjectivityData{
-			BlockRoot: blockRoot,
-			StateRoot: stateRoot,
-			Epoch:     epoch,
-		},
-		st: st,
-		sb: stateBytes,
-		b:  block,
-		bb: blockBytes,
-		cf: cf,
-	}, nil
-}
-
-// DownloadOriginData attempts to use the proposed weak_subjectivity beacon node api
-// to obtain the weak_subjectivity metadata (epoch, block_root, state_root) needed to sync
-// a beacon node from the canonical weak subjectivity checkpoint. As this is a proposed API
-// that will only be supported by prysm at first, in the event of a 404 we fallback to using a
-// different technique where we first download the head state which can be used to compute the
-// weak subjectivity epoch on the client side.
-func DownloadOriginData(ctx context.Context, client *Client) (*OriginData, error) {
-	ws, err := client.GetWeakSubjectivity(ctx)
-	if err != nil {
-		// a 404/405 is expected if querying an endpoint that doesn't support the weak subjectivity checkpoint api
-		if !errors.Is(err, ErrNotOK) {
-			return nil, errors.Wrap(err, "unexpected API response for prysm-only weak subjectivity checkpoint API")
-		}
-		// fall back to vanilla Beacon Node API method
-		return downloadBackwardsCompatible(ctx, client)
-	}
-	log.Printf("server weak subjectivity checkpoint response - epoch=%d, block_root=%#x, state_root=%#x", ws.Epoch, ws.BlockRoot, ws.StateRoot)
-
-	// use first slot of the epoch for the block slot
-	slot, err := slots.EpochStart(ws.Epoch)
-	if err != nil {
-		return nil, errors.Wrapf(err, "error computing first slot of epoch=%d", ws.Epoch)
-	}
-	log.Printf("requesting checkpoint state at slot %d", slot)
-
-	stateBytes, err := client.GetState(ctx, IdFromSlot(slot))
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to request state by slot from api, slot=%d", slot)
-	}
-	cf, err := detect.FromState(stateBytes)
-	if err != nil {
-		return nil, errors.Wrap(err, "error detecting chain config for beacon state")
-	}
-	log.Printf("detected supported config in checkpoint state, name=%s, fork=%s", cf.Config.ConfigName, version.String(cf.Fork))
-
-	state, err := cf.UnmarshalBeaconState(stateBytes)
-	if err != nil {
-		return nil, errors.Wrap(err, "error using detected config fork to unmarshal state bytes")
-	}
-	stateRoot, err := state.HashTreeRoot(ctx)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to compute htr for state at slot=%d", slot)
-	}
-
-	blockRoot, err := state.LatestBlockHeader().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root of latest_block_header")
-	}
-	blockBytes, err := client.GetBlock(ctx, IdFromRoot(ws.BlockRoot))
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting block by slot = %d", slot)
-	}
-	block, err := cf.UnmarshalBeaconBlock(blockBytes)
-	if err != nil {
-		return nil, errors.Wrap(err, "unable to unmarshal block to a supported type using the detected fork schedule")
-	}
-	realBlockRoot, err := block.Block().HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error computing hash_tree_root of retrieved block")
-	}
-	log.Printf("BeaconState slot=%d, Block slot=%d", state.Slot(), block.Block().Slot())
-	log.Printf("BeaconState htr=%#xd, Block state_root=%#x", stateRoot, block.Block().StateRoot())
-	log.Printf("BeaconState latest_block_header htr=%#xd, block htr=%#x", blockRoot, realBlockRoot)
-	return &OriginData{
-		wsd: ws,
-		st:  state,
-		b:   block,
-		sb:  stateBytes,
-		bb:  blockBytes,
-		cf:  cf,
-	}, nil
-}
--- a/api/client/beacon/checkpoint_test.go
+++ b/api/client/beacon/checkpoint_test.go
@@ -1,407 +0,0 @@
-package beacon
-
-import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"fmt"
-	"io"
-	"net/http"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/network/forks"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	"github.com/prysmaticlabs/prysm/time/slots"
-
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/ssz/detect"
-	"github.com/prysmaticlabs/prysm/runtime/version"
-
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-type testRT struct {
-	rt func(*http.Request) (*http.Response, error)
-}
-
-func (rt *testRT) RoundTrip(req *http.Request) (*http.Response, error) {
-	if rt.rt != nil {
-		return rt.rt(req)
-	}
-	return nil, errors.New("RoundTripper not implemented")
-}
-
-var _ http.RoundTripper = &testRT{}
-
-func marshalToEnvelope(val interface{}) ([]byte, error) {
-	raw, err := json.Marshal(val)
-	if err != nil {
-		return nil, errors.Wrap(err, "error marshaling value to place in data envelope")
-	}
-	env := struct {
-		Data json.RawMessage `json:"data"`
-	}{
-		Data: raw,
-	}
-	return json.Marshal(env)
-}
-
-func TestMarshalToEnvelope(t *testing.T) {
-	d := struct {
-		Version string `json:"version"`
-	}{
-		Version: "Prysm/v2.0.5 (linux amd64)",
-	}
-	encoded, err := marshalToEnvelope(d)
-	require.NoError(t, err)
-	expected := `{"data":{"version":"Prysm/v2.0.5 (linux amd64)"}}`
-	require.Equal(t, expected, string(encoded))
-}
-
-func TestFallbackVersionCheck(t *testing.T) {
-	c := &Client{
-		hc:     &http.Client{},
-		host:   "localhost:3500",
-		scheme: "http",
-	}
-	c.hc.Transport = &testRT{rt: func(req *http.Request) (*http.Response, error) {
-		res := &http.Response{Request: req}
-		switch req.URL.Path {
-		case getNodeVersionPath:
-			res.StatusCode = http.StatusOK
-			b := bytes.NewBuffer(nil)
-			d := struct {
-				Version string `json:"version"`
-			}{
-				Version: "Prysm/v2.0.5 (linux amd64)",
-			}
-			encoded, err := marshalToEnvelope(d)
-			require.NoError(t, err)
-			b.Write(encoded)
-			res.Body = io.NopCloser(b)
-		case getWeakSubjectivityPath:
-			res.StatusCode = http.StatusNotFound
-		}
-
-		return res, nil
-	}}
-
-	ctx := context.Background()
-	_, err := DownloadOriginData(ctx, c)
-	require.ErrorIs(t, err, ErrUnsupportedPrysmCheckpointVersion)
-}
-
-func TestFname(t *testing.T) {
-	vu := &detect.VersionedUnmarshaler{
-		Config: params.MainnetConfig(),
-		Fork:   version.Phase0,
-	}
-	slot := types.Slot(23)
-	prefix := "block"
-	var root [32]byte
-	copy(root[:], []byte{0x23, 0x23, 0x23})
-	expected := "block_mainnet_phase0_23-0x2323230000000000000000000000000000000000000000000000000000000000.ssz"
-	actual := fname(prefix, vu, slot, root)
-	require.Equal(t, expected, actual)
-
-	vu.Config = params.MinimalSpecConfig()
-	vu.Fork = version.Altair
-	slot = 17
-	prefix = "state"
-	copy(root[29:], []byte{0x17, 0x17, 0x17})
-	expected = "state_minimal_altair_17-0x2323230000000000000000000000000000000000000000000000000000171717.ssz"
-	actual = fname(prefix, vu, slot, root)
-	require.Equal(t, expected, actual)
-}
-
-func TestDownloadOriginData(t *testing.T) {
-	ctx := context.Background()
-	cfg := params.MainnetConfig()
-
-	epoch := cfg.AltairForkEpoch - 1
-	// set up checkpoint state, using the epoch that will be computed as the ws checkpoint state based on the head state
-	wSlot, err := slots.EpochStart(epoch)
-	require.NoError(t, err)
-	wst, err := util.NewBeaconState()
-	require.NoError(t, err)
-	fork, err := forkForEpoch(cfg, epoch)
-	require.NoError(t, wst.SetFork(fork))
-
-	// set up checkpoint block
-	b, err := wrapper.WrappedSignedBeaconBlock(util.NewBeaconBlock())
-	require.NoError(t, wrapper.SetBlockParentRoot(b, cfg.ZeroHash))
-	require.NoError(t, wrapper.SetBlockSlot(b, wSlot))
-	require.NoError(t, wrapper.SetProposerIndex(b, 0))
-
-	// set up state header pointing at checkpoint block - this is how the block is downloaded by root
-	header, err := b.Header()
-	require.NoError(t, err)
-	require.NoError(t, wst.SetLatestBlockHeader(header.Header))
-
-	// order of operations can be confusing here:
-	// - when computing the state root, make sure block header is complete, EXCEPT the state root should be zero-value
-	// - before computing the block root (to match the request route), the block should include the state root
-	//   *computed from the state with a header that does not have a state root set yet*
-	wRoot, err := wst.HashTreeRoot(ctx)
-	require.NoError(t, err)
-
-	require.NoError(t, wrapper.SetBlockStateRoot(b, wRoot))
-	serBlock, err := b.MarshalSSZ()
-	require.NoError(t, err)
-	bRoot, err := b.Block().HashTreeRoot()
-	require.NoError(t, err)
-
-	wsSerialized, err := wst.MarshalSSZ()
-	require.NoError(t, err)
-	expectedWSD := WeakSubjectivityData{
-		BlockRoot: bRoot,
-		StateRoot: wRoot,
-		Epoch:     epoch,
-	}
-
-	hc := &http.Client{
-		Transport: &testRT{rt: func(req *http.Request) (*http.Response, error) {
-			res := &http.Response{Request: req}
-			switch req.URL.Path {
-			case getWeakSubjectivityPath:
-				res.StatusCode = http.StatusOK
-				cp := struct {
-					Epoch string `json:"epoch"`
-					Root  string `json:"root"`
-				}{
-					Epoch: fmt.Sprintf("%d", slots.ToEpoch(b.Block().Slot())),
-					Root:  fmt.Sprintf("%#x", bRoot),
-				}
-				wsr := struct {
-					Checkpoint interface{} `json:"ws_checkpoint"`
-					StateRoot  string      `json:"state_root"`
-				}{
-					Checkpoint: cp,
-					StateRoot:  fmt.Sprintf("%#x", wRoot),
-				}
-				rb, err := marshalToEnvelope(wsr)
-				require.NoError(t, err)
-				res.Body = io.NopCloser(bytes.NewBuffer(rb))
-			case renderGetStatePath(IdFromSlot(wSlot)):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(wsSerialized))
-			case renderGetBlockPath(IdFromRoot(bRoot)):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(serBlock))
-			}
-
-			return res, nil
-		}},
-	}
-	c := &Client{
-		hc:     hc,
-		host:   "localhost:3500",
-		scheme: "http",
-	}
-
-	od, err := DownloadOriginData(ctx, c)
-	require.NoError(t, err)
-	require.Equal(t, expectedWSD.Epoch, od.wsd.Epoch)
-	require.Equal(t, expectedWSD.StateRoot, od.wsd.StateRoot)
-	require.Equal(t, expectedWSD.BlockRoot, od.wsd.BlockRoot)
-	require.DeepEqual(t, wsSerialized, od.sb)
-	require.DeepEqual(t, serBlock, od.bb)
-	require.DeepEqual(t, wst.Fork().CurrentVersion, od.cf.Version[:])
-	require.DeepEqual(t, version.Phase0, od.cf.Fork)
-}
-
-// runs downloadBackwardsCompatible directly
-// and via DownloadOriginData with a round tripper that triggers the backwards compatible code path
-func TestDownloadBackwardsCompatibleCombined(t *testing.T) {
-	ctx := context.Background()
-	cfg := params.MainnetConfig()
-
-	st, expectedEpoch := defaultTestHeadState(t, cfg)
-	serialized, err := st.MarshalSSZ()
-	require.NoError(t, err)
-
-	// set up checkpoint state, using the epoch that will be computed as the ws checkpoint state based on the head state
-	wSlot, err := slots.EpochStart(expectedEpoch)
-	require.NoError(t, err)
-	wst, err := util.NewBeaconState()
-	require.NoError(t, err)
-	fork, err := forkForEpoch(cfg, cfg.GenesisEpoch)
-	require.NoError(t, wst.SetFork(fork))
-
-	// set up checkpoint block
-	b, err := wrapper.WrappedSignedBeaconBlock(util.NewBeaconBlock())
-	require.NoError(t, wrapper.SetBlockParentRoot(b, cfg.ZeroHash))
-	require.NoError(t, wrapper.SetBlockSlot(b, wSlot))
-	require.NoError(t, wrapper.SetProposerIndex(b, 0))
-
-	// set up state header pointing at checkpoint block - this is how the block is downloaded by root
-	header, err := b.Header()
-	require.NoError(t, err)
-	require.NoError(t, wst.SetLatestBlockHeader(header.Header))
-
-	// order of operations can be confusing here:
-	// - when computing the state root, make sure block header is complete, EXCEPT the state root should be zero-value
-	// - before computing the block root (to match the request route), the block should include the state root
-	//   *computed from the state with a header that does not have a state root set yet*
-	wRoot, err := wst.HashTreeRoot(ctx)
-	require.NoError(t, err)
-
-	require.NoError(t, wrapper.SetBlockStateRoot(b, wRoot))
-	serBlock, err := b.MarshalSSZ()
-	require.NoError(t, err)
-	bRoot, err := b.Block().HashTreeRoot()
-	require.NoError(t, err)
-
-	wsSerialized, err := wst.MarshalSSZ()
-	require.NoError(t, err)
-
-	hc := &http.Client{
-		Transport: &testRT{rt: func(req *http.Request) (*http.Response, error) {
-			res := &http.Response{Request: req}
-			switch req.URL.Path {
-			case getNodeVersionPath:
-				res.StatusCode = http.StatusOK
-				b := bytes.NewBuffer(nil)
-				d := struct {
-					Version string `json:"version"`
-				}{
-					Version: "Lighthouse/v0.1.5 (Linux x86_64)",
-				}
-				encoded, err := marshalToEnvelope(d)
-				require.NoError(t, err)
-				b.Write(encoded)
-				res.Body = io.NopCloser(b)
-			case getWeakSubjectivityPath:
-				res.StatusCode = http.StatusNotFound
-			case renderGetStatePath(IdHead):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(serialized))
-			case renderGetStatePath(IdFromSlot(wSlot)):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(wsSerialized))
-			case renderGetBlockPath(IdFromRoot(bRoot)):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(serBlock))
-			}
-
-			return res, nil
-		}},
-	}
-	c := &Client{
-		hc:     hc,
-		host:   "localhost:3500",
-		scheme: "http",
-	}
-
-	odPub, err := DownloadOriginData(ctx, c)
-	require.NoError(t, err)
-
-	odPriv, err := downloadBackwardsCompatible(ctx, c)
-	require.NoError(t, err)
-	require.DeepEqual(t, odPriv.wsd, odPub.wsd)
-	require.DeepEqual(t, odPriv.sb, odPub.sb)
-	require.DeepEqual(t, odPriv.bb, odPub.bb)
-	require.DeepEqual(t, odPriv.cf.Fork, odPub.cf.Fork)
-	require.DeepEqual(t, odPriv.cf.Version, odPub.cf.Version)
-}
-
-func TestGetWeakSubjectivityEpochFromHead(t *testing.T) {
-	st, expectedEpoch := defaultTestHeadState(t, params.MainnetConfig())
-	serialized, err := st.MarshalSSZ()
-	require.NoError(t, err)
-	hc := &http.Client{
-		Transport: &testRT{rt: func(req *http.Request) (*http.Response, error) {
-			res := &http.Response{Request: req}
-			switch req.URL.Path {
-			case renderGetStatePath(IdHead):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(serialized))
-			}
-			return res, nil
-		}},
-	}
-	c := &Client{
-		hc:     hc,
-		host:   "localhost:3500",
-		scheme: "http",
-	}
-	actualEpoch, err := getWeakSubjectivityEpochFromHead(context.Background(), c)
-	require.NoError(t, err)
-	require.Equal(t, expectedEpoch, actualEpoch)
-}
-
-func forkForEpoch(cfg *params.BeaconChainConfig, epoch types.Epoch) (*ethpb.Fork, error) {
-	os := forks.NewOrderedSchedule(cfg)
-	currentVersion, err := os.VersionForEpoch(epoch)
-	if err != nil {
-		return nil, err
-	}
-	prevVersion, err := os.Previous(currentVersion)
-	if err != nil {
-		if !errors.Is(err, forks.ErrNoPreviousVersion) {
-			return nil, err
-		}
-		// use same version for both in the case of genesis
-		prevVersion = currentVersion
-	}
-	forkEpoch := cfg.ForkVersionSchedule[currentVersion]
-	return &ethpb.Fork{
-		PreviousVersion: prevVersion[:],
-		CurrentVersion:  currentVersion[:],
-		Epoch:           forkEpoch,
-	}, nil
-}
-
-func defaultTestHeadState(t *testing.T, cfg *params.BeaconChainConfig) (state.BeaconState, types.Epoch) {
-	st, err := util.NewBeaconStateAltair()
-	require.NoError(t, err)
-
-	fork, err := forkForEpoch(cfg, cfg.AltairForkEpoch)
-	require.NoError(t, err)
-	require.NoError(t, st.SetFork(fork))
-
-	slot, err := slots.EpochStart(cfg.AltairForkEpoch)
-	require.NoError(t, err)
-	require.NoError(t, st.SetSlot(slot))
-
-	var validatorCount, avgBalance uint64 = 100, 35
-	require.NoError(t, populateValidators(cfg, st, validatorCount, avgBalance))
-	require.NoError(t, st.SetFinalizedCheckpoint(&ethpb.Checkpoint{
-		Epoch: fork.Epoch - 10,
-		Root:  make([]byte, 32),
-	}))
-	// to see the math for this, look at helpers.LatestWeakSubjectivityEpoch
-	// and for the values use mainnet config values, the validatorCount and avgBalance above, and altair fork epoch
-	expectedEpoch := slots.ToEpoch(st.Slot()) - 224
-	return st, expectedEpoch
-}
-
-// TODO(10429): refactor beacon state options in testing/util to take a state.BeaconState so this can become an option
-func populateValidators(cfg *params.BeaconChainConfig, st state.BeaconState, valCount, avgBalance uint64) error {
-	validators := make([]*ethpb.Validator, valCount)
-	balances := make([]uint64, len(validators))
-	for i := uint64(0); i < valCount; i++ {
-		validators[i] = &ethpb.Validator{
-			PublicKey:             make([]byte, cfg.BLSPubkeyLength),
-			WithdrawalCredentials: make([]byte, 32),
-			EffectiveBalance:      avgBalance * 1e9,
-			ExitEpoch:             cfg.FarFutureEpoch,
-		}
-		balances[i] = validators[i].EffectiveBalance
-	}
-
-	if err := st.SetValidators(validators); err != nil {
-		return err
-	}
-	if err := st.SetBalances(balances); err != nil {
-		return err
-	}
-
-	return nil
-}
--- a/api/client/beacon/client.go
+++ b/api/client/beacon/client.go
@@ -1,446 +0,0 @@
-package beacon
-
-import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"net"
-	"net/http"
-	"net/url"
-	"path"
-	"regexp"
-	"sort"
-	"strconv"
-	"text/template"
-	"time"
-
-	"github.com/prysmaticlabs/prysm/network/forks"
-
-	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/rpc/apimiddleware"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	log "github.com/sirupsen/logrus"
-)
-
-const (
-	getSignedBlockPath      = "/eth/v2/beacon/blocks"
-	getBlockRootPath        = "/eth/v1/beacon/blocks/{{.Id}}/root"
-	getForkForStatePath     = "/eth/v1/beacon/states/{{.Id}}/fork"
-	getWeakSubjectivityPath = "/eth/v1/beacon/weak_subjectivity"
-	getForkSchedulePath     = "/eth/v1/config/fork_schedule"
-	getStatePath            = "/eth/v2/debug/beacon/states"
-	getNodeVersionPath      = "/eth/v1/node/version"
-)
-
-// StateOrBlockId represents the block_id / state_id parameters that several of the Eth Beacon API methods accept.
-// StateOrBlockId constants are defined for named identifiers, and helper methods are provided
-// for slot and root identifiers. Example text from the Eth Beacon Node API documentation:
-//
-// "Block identifier can be one of: "head" (canonical head in node's view), "genesis", "finalized",
-// <slot>, <hex encoded blockRoot with 0x prefix>."
-type StateOrBlockId string
-
-const (
-	IdFinalized StateOrBlockId = "finalized"
-	IdGenesis   StateOrBlockId = "genesis"
-	IdHead      StateOrBlockId = "head"
-	IdJustified StateOrBlockId = "justified"
-)
-
-// IdFromRoot encodes a block root in the format expected by the API in places where a root can be used to identify
-// a BeaconState or SignedBeaconBlock.
-func IdFromRoot(r [32]byte) StateOrBlockId {
-	return StateOrBlockId(fmt.Sprintf("%#x", r))
-}
-
-// IdFromRoot encodes a Slot in the format expected by the API in places where a slot can be used to identify
-// a BeaconState or SignedBeaconBlock.
-func IdFromSlot(s types.Slot) StateOrBlockId {
-	return StateOrBlockId(strconv.FormatUint(uint64(s), 10))
-}
-
-// idTemplate is used to create template functions that can interpolate StateOrBlockId values.
-func idTemplate(ts string) func(StateOrBlockId) string {
-	t := template.Must(template.New("").Parse(ts))
-	f := func(id StateOrBlockId) string {
-		b := bytes.NewBuffer(nil)
-		err := t.Execute(b, struct{ Id string }{Id: string(id)})
-		if err != nil {
-			panic(fmt.Sprintf("invalid idTemplate: %s", ts))
-		}
-		return b.String()
-	}
-	// run the template to ensure that it is valid
-	// this should happen load time (using package scoped vars) to ensure runtime errors aren't possible
-	_ = f(IdGenesis)
-	return f
-}
-
-// ClientOpt is a functional option for the Client type (http.Client wrapper)
-type ClientOpt func(*Client)
-
-// WithTimeout sets the .Timeout attribute of the wrapped http.Client.
-func WithTimeout(timeout time.Duration) ClientOpt {
-	return func(c *Client) {
-		c.hc.Timeout = timeout
-	}
-}
-
-// Client provides a collection of helper methods for calling the Eth Beacon Node API endpoints.
-type Client struct {
-	hc     *http.Client
-	host   string
-	scheme string
-}
-
-// NewClient constructs a new client with the provided options (ex WithTimeout).
-// `host` is the base host + port used to construct request urls. This value can be
-// a URL string, or NewClient will assume an http endpoint if just `host:port` is used.
-func NewClient(host string, opts ...ClientOpt) (*Client, error) {
-	host, err := validHostname(host)
-	if err != nil {
-		return nil, err
-	}
-	c := &Client{
-		hc:     &http.Client{},
-		scheme: "http",
-		host:   host,
-	}
-	for _, o := range opts {
-		o(c)
-	}
-	return c, nil
-}
-
-func validHostname(h string) (string, error) {
-	// try to parse as url (being permissive)
-	u, err := url.Parse(h)
-	if err == nil && u.Host != "" {
-		return u.Host, nil
-	}
-	// try to parse as host:port
-	host, port, err := net.SplitHostPort(h)
-	if err != nil {
-		return "", err
-	}
-	return fmt.Sprintf("%s:%s", host, port), nil
-}
-
-// NodeURL returns a human-readable string representation of the beacon node base url.
-func (c *Client) NodeURL() string {
-	u := &url.URL{
-		Scheme: c.scheme,
-		Host:   c.host,
-	}
-	return u.String()
-}
-
-func (c *Client) urlForPath(methodPath string) *url.URL {
-	u := &url.URL{
-		Scheme: c.scheme,
-		Host:   c.host,
-	}
-	u.Path = path.Join(u.Path, methodPath)
-	return u
-}
-
-type reqOption func(*http.Request)
-
-func withSSZEncoding() reqOption {
-	return func(req *http.Request) {
-		req.Header.Set("Accept", "application/octet-stream")
-	}
-}
-
-// get is a generic, opinionated GET function to reduce boilerplate amongst the getters in this package.
-func (c *Client) get(ctx context.Context, path string, opts ...reqOption) ([]byte, error) {
-	u := c.urlForPath(path)
-	log.Printf("requesting %s", u.String())
-	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
-	if err != nil {
-		return nil, err
-	}
-	for _, o := range opts {
-		o(req)
-	}
-	r, err := c.hc.Do(req)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		err = r.Body.Close()
-	}()
-	if r.StatusCode != http.StatusOK {
-		return nil, non200Err(r)
-	}
-	b, err := io.ReadAll(r.Body)
-	if err != nil {
-		return nil, errors.Wrap(err, "error reading http response body from GetBlock")
-	}
-	return b, nil
-}
-
-func renderGetBlockPath(id StateOrBlockId) string {
-	return path.Join(getSignedBlockPath, string(id))
-}
-
-// GetBlock retrieves the SignedBeaconBlock for the given block id.
-// Block identifier can be one of: "head" (canonical head in node's view), "genesis", "finalized",
-// <slot>, <hex encoded blockRoot with 0x prefix>. Variables of type StateOrBlockId are exported by this package
-// for the named identifiers.
-// The return value contains the ssz-encoded bytes.
-func (c *Client) GetBlock(ctx context.Context, blockId StateOrBlockId) ([]byte, error) {
-	blockPath := renderGetBlockPath(blockId)
-	b, err := c.get(ctx, blockPath, withSSZEncoding())
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting state by id = %s", blockId)
-	}
-	return b, nil
-}
-
-var getBlockRootTpl = idTemplate(getBlockRootPath)
-
-// GetBlockRoot retrieves the hash_tree_root of the BeaconBlock for the given block id.
-// Block identifier can be one of: "head" (canonical head in node's view), "genesis", "finalized",
-// <slot>, <hex encoded blockRoot with 0x prefix>. Variables of type StateOrBlockId are exported by this package
-// for the named identifiers.
-func (c *Client) GetBlockRoot(ctx context.Context, blockId StateOrBlockId) ([32]byte, error) {
-	rootPath := getBlockRootTpl(blockId)
-	b, err := c.get(ctx, rootPath)
-	if err != nil {
-		return [32]byte{}, errors.Wrapf(err, "error requesting block root by id = %s", blockId)
-	}
-	jsonr := &struct{ Data struct{ Root string } }{}
-	err = json.Unmarshal(b, jsonr)
-	if err != nil {
-		return [32]byte{}, errors.Wrap(err, "error decoding json data from get block root response")
-	}
-	rs, err := hexutil.Decode(jsonr.Data.Root)
-	if err != nil {
-		return [32]byte{}, errors.Wrap(err, fmt.Sprintf("error decoding hex-encoded value %s", jsonr.Data.Root))
-	}
-	return bytesutil.ToBytes32(rs), nil
-}
-
-var getForkTpl = idTemplate(getForkForStatePath)
-
-// GetFork queries the Beacon Node API for the Fork from the state identified by stateId.
-// Block identifier can be one of: "head" (canonical head in node's view), "genesis", "finalized",
-// <slot>, <hex encoded blockRoot with 0x prefix>. Variables of type StateOrBlockId are exported by this package
-// for the named identifiers.
-func (c *Client) GetFork(ctx context.Context, stateId StateOrBlockId) (*ethpb.Fork, error) {
-	body, err := c.get(ctx, getForkTpl(stateId))
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting fork by state id = %s", stateId)
-	}
-	fr := &forkResponse{}
-	dataWrapper := &struct{ Data *forkResponse }{Data: fr}
-	err = json.Unmarshal(body, dataWrapper)
-	if err != nil {
-		return nil, errors.Wrap(err, "error decoding json response in GetFork")
-	}
-
-	return fr.Fork()
-}
-
-// GetForkSchedule retrieve all forks, past present and future, of which this node is aware.
-func (c *Client) GetForkSchedule(ctx context.Context) (forks.OrderedSchedule, error) {
-	body, err := c.get(ctx, getForkSchedulePath)
-	if err != nil {
-		return nil, errors.Wrap(err, "error requesting fork schedule")
-	}
-	fsr := &forkScheduleResponse{}
-	err = json.Unmarshal(body, fsr)
-	if err != nil {
-		return nil, err
-	}
-	ofs, err := fsr.OrderedForkSchedule()
-	if err != nil {
-		return nil, errors.Wrap(err, fmt.Sprintf("problem unmarshaling %s response", getForkSchedulePath))
-	}
-	return ofs, nil
-}
-
-type NodeVersion struct {
-	implementation string
-	semver         string
-	systemInfo     string
-}
-
-var versionRE = regexp.MustCompile(`^(\w+)\/(v\d+\.\d+\.\d+) \((.*)\)$`)
-
-func parseNodeVersion(v string) (*NodeVersion, error) {
-	groups := versionRE.FindStringSubmatch(v)
-	if len(groups) != 4 {
-		return nil, errors.Wrapf(ErrInvalidNodeVersion, "could not be parsed: %s", v)
-	}
-	return &NodeVersion{
-		implementation: groups[1],
-		semver:         groups[2],
-		systemInfo:     groups[3],
-	}, nil
-}
-
-// GetNodeVersion requests that the beacon node identify information about its implementation in a format
-// similar to a HTTP User-Agent field. ex: Lighthouse/v0.1.5 (Linux x86_64)
-func (c *Client) GetNodeVersion(ctx context.Context) (*NodeVersion, error) {
-	b, err := c.get(ctx, getNodeVersionPath)
-	if err != nil {
-		return nil, errors.Wrap(err, "error requesting node version")
-	}
-	d := struct {
-		Data struct {
-			Version string `json:"version"`
-		} `json:"data"`
-	}{}
-	err = json.Unmarshal(b, &d)
-	if err != nil {
-		return nil, errors.Wrapf(err, "error unmarshaling response body: %s", string(b))
-	}
-	return parseNodeVersion(d.Data.Version)
-}
-
-func renderGetStatePath(id StateOrBlockId) string {
-	return path.Join(getStatePath, string(id))
-}
-
-// GetState retrieves the BeaconState for the given state id.
-// State identifier can be one of: "head" (canonical head in node's view), "genesis", "finalized",
-// <slot>, <hex encoded stateRoot with 0x prefix>. Variables of type StateOrBlockId are exported by this package
-// for the named identifiers.
-// The return value contains the ssz-encoded bytes.
-func (c *Client) GetState(ctx context.Context, stateId StateOrBlockId) ([]byte, error) {
-	statePath := path.Join(getStatePath, string(stateId))
-	b, err := c.get(ctx, statePath, withSSZEncoding())
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting state by id = %s", stateId)
-	}
-	return b, nil
-}
-
-// GetWeakSubjectivity calls a proposed API endpoint that is unique to prysm
-// This api method does the following:
-// - computes weak subjectivity epoch
-// - finds the highest non-skipped block preceding the epoch
-// - returns the htr of the found block and returns this + the value of state_root from the block
-func (c *Client) GetWeakSubjectivity(ctx context.Context) (*WeakSubjectivityData, error) {
-	body, err := c.get(ctx, getWeakSubjectivityPath)
-	if err != nil {
-		return nil, err
-	}
-	v := &apimiddleware.WeakSubjectivityResponse{}
-	err = json.Unmarshal(body, v)
-	if err != nil {
-		return nil, err
-	}
-	epoch, err := strconv.ParseUint(v.Data.Checkpoint.Epoch, 10, 64)
-	if err != nil {
-		return nil, err
-	}
-	blockRoot, err := hexutil.Decode(v.Data.Checkpoint.Root)
-	if err != nil {
-		return nil, err
-	}
-	stateRoot, err := hexutil.Decode(v.Data.StateRoot)
-	if err != nil {
-		return nil, err
-	}
-	return &WeakSubjectivityData{
-		Epoch:     types.Epoch(epoch),
-		BlockRoot: bytesutil.ToBytes32(blockRoot),
-		StateRoot: bytesutil.ToBytes32(stateRoot),
-	}, nil
-}
-
-// WeakSubjectivityData represents the state root, block root and epoch of the BeaconState + SignedBeaconBlock
-// that falls at the beginning of the current weak subjectivity period. These values can be used to construct
-// a weak subjectivity checkpoint, or to download a BeaconState+SignedBeaconBlock pair that can be used to bootstrap
-// a new Beacon Node using Checkpoint Sync.
-type WeakSubjectivityData struct {
-	BlockRoot [32]byte
-	StateRoot [32]byte
-	Epoch     types.Epoch
-}
-
-func non200Err(response *http.Response) error {
-	bodyBytes, err := ioutil.ReadAll(response.Body)
-	var body string
-	if err != nil {
-		body = "(Unable to read response body.)"
-	} else {
-		body = "response body:\n" + string(bodyBytes)
-	}
-	msg := fmt.Sprintf("code=%d, url=%s, body=%s", response.StatusCode, response.Request.URL, body)
-	switch response.StatusCode {
-	case 404:
-		return errors.Wrap(ErrNotFound, msg)
-	default:
-		return errors.Wrap(ErrNotOK, msg)
-	}
-}
-
-type forkResponse struct {
-	PreviousVersion string `json:"previous_version"`
-	CurrentVersion  string `json:"current_version"`
-	Epoch           string `json:"epoch"`
-}
-
-func (f *forkResponse) Fork() (*ethpb.Fork, error) {
-	epoch, err := strconv.ParseUint(f.Epoch, 10, 64)
-	if err != nil {
-		return nil, err
-	}
-	cSlice, err := hexutil.Decode(f.CurrentVersion)
-	if err != nil {
-		return nil, err
-	}
-	if len(cSlice) != 4 {
-		return nil, fmt.Errorf("got %d byte version for CurrentVersion, expected 4 bytes. hex=%s", len(cSlice), f.CurrentVersion)
-	}
-	pSlice, err := hexutil.Decode(f.PreviousVersion)
-	if err != nil {
-		return nil, err
-	}
-	if len(pSlice) != 4 {
-		return nil, fmt.Errorf("got %d byte version, expected 4 bytes. version hex=%s", len(pSlice), f.PreviousVersion)
-	}
-	return &ethpb.Fork{
-		CurrentVersion:  cSlice,
-		PreviousVersion: pSlice,
-		Epoch:           types.Epoch(epoch),
-	}, nil
-}
-
-type forkScheduleResponse struct {
-	Data []forkResponse
-}
-
-func (fsr *forkScheduleResponse) OrderedForkSchedule() (forks.OrderedSchedule, error) {
-	ofs := make(forks.OrderedSchedule, 0)
-	for _, d := range fsr.Data {
-		epoch, err := strconv.Atoi(d.Epoch)
-		if err != nil {
-			return nil, err
-		}
-		vSlice, err := hexutil.Decode(d.CurrentVersion)
-		if err != nil {
-			return nil, err
-		}
-		if len(vSlice) != 4 {
-			return nil, fmt.Errorf("got %d byte version, expected 4 bytes. version hex=%s", len(vSlice), d.CurrentVersion)
-		}
-		version := bytesutil.ToBytes4(vSlice)
-		ofs = append(ofs, forks.ForkScheduleEntry{
-			Version: version,
-			Epoch:   types.Epoch(uint64(epoch)),
-		})
-	}
-	sort.Sort(ofs)
-	return ofs, nil
-}
--- a/api/client/beacon/client_test.go
+++ b/api/client/beacon/client_test.go
@@ -1,58 +0,0 @@
-package beacon
-
-import (
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-func TestParseNodeVersion(t *testing.T) {
-	cases := []struct {
-		name string
-		v    string
-		err  error
-		nv   *NodeVersion
-	}{
-		{
-			name: "empty string",
-			v:    "",
-			err:  ErrInvalidNodeVersion,
-		},
-		{
-			name: "Prysm as the version string",
-			v:    "Prysm",
-			err:  ErrInvalidNodeVersion,
-		},
-		{
-			name: "semver only",
-			v:    "v2.0.6",
-			err:  ErrInvalidNodeVersion,
-		},
-		{
-			name: "implementation and semver only",
-			v:    "Prysm/v2.0.6",
-			err:  ErrInvalidNodeVersion,
-		},
-		{
-			name: "complete version",
-			v:    "Prysm/v2.0.6 (linux amd64)",
-			nv: &NodeVersion{
-				implementation: "Prysm",
-				semver:         "v2.0.6",
-				systemInfo:     "linux amd64",
-			},
-		},
-	}
-
-	for _, c := range cases {
-		t.Run(c.name, func(t *testing.T) {
-			nv, err := parseNodeVersion(c.v)
-			if c.err != nil {
-				require.ErrorIs(t, err, c.err)
-			} else {
-				require.NoError(t, err)
-				require.DeepEqual(t, c.nv, nv)
-			}
-		})
-	}
-}
--- a/api/client/beacon/doc.go
+++ b/api/client/beacon/doc.go
@@ -1,6 +0,0 @@
-/*
-Package beacon provides a client for interacting with the standard Eth Beacon Node API.
-Interactive swagger documentation for the API is available here: https://ethereum.github.io/beacon-APIs/
-
-*/
-package beacon
--- a/api/client/beacon/errors.go
+++ b/api/client/beacon/errors.go
@@ -1,13 +0,0 @@
-package beacon
-
-import "github.com/pkg/errors"
-
-// ErrNotOK is used to indicate when an HTTP request to the Beacon Node API failed with any non-2xx response code.
-// More specific errors may be returned, but an error in reaction to a non-2xx response will always wrap ErrNotOK.
-var ErrNotOK = errors.New("did not receive 2xx response from API")
-
-// ErrNotFound specifically means that a '404 - NOT FOUND' response was received from the API.
-var ErrNotFound = errors.Wrap(ErrNotOK, "recv 404 NotFound response from API")
-
-// ErrInvalidNodeVersion indicates that the /eth/v1/node/version api response format was not recognized.
-var ErrInvalidNodeVersion = errors.New("invalid node version response")
--- a/api/gateway/BUILD.bazel
+++ b/api/gateway/BUILD.bazel
@@ -1,42 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "gateway.go",
-        "log.go",
-        "options.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/api/gateway",
-    visibility = [
-        "//beacon-chain:__subpackages__",
-        "//validator:__subpackages__",
-    ],
-    deps = [
-        "//api/gateway/apimiddleware:go_default_library",
-        "//runtime:go_default_library",
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_grpc_ecosystem_grpc_gateway_v2//runtime:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@com_github_rs_cors//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@org_golang_google_grpc//:go_default_library",
-        "@org_golang_google_grpc//connectivity:go_default_library",
-        "@org_golang_google_grpc//credentials:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["gateway_test.go"],
-    embed = [":go_default_library"],
-    deps = [
-        "//api/gateway/apimiddleware:go_default_library",
-        "//cmd/beacon-chain/flags:go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
-        "@com_github_urfave_cli_v2//:go_default_library",
-    ],
-)
--- a/api/gateway/apimiddleware/BUILD.bazel
+++ b/api/gateway/apimiddleware/BUILD.bazel
@@ -1,40 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "api_middleware.go",
-        "log.go",
-        "param_handling.go",
-        "process_field.go",
-        "process_request.go",
-        "structs.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/api/gateway/apimiddleware",
-    visibility = ["//visibility:public"],
-    deps = [
-        "//api/grpc:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@com_github_wealdtech_go_bytesutil//:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = [
-        "param_handling_test.go",
-        "process_request_test.go",
-    ],
-    embed = [":go_default_library"],
-    deps = [
-        "//api/grpc:go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
-    ],
-)
--- a/api/gateway/apimiddleware/api_middleware.go
+++ b/api/gateway/apimiddleware/api_middleware.go
@@ -1,265 +0,0 @@
-package apimiddleware
-
-import (
-	"net/http"
-	"reflect"
-	"time"
-
-	"github.com/gorilla/mux"
-)
-
-// ApiProxyMiddleware is a proxy between an Ethereum consensus API HTTP client and grpc-gateway.
-// The purpose of the proxy is to handle HTTP requests and gRPC responses in such a way that:
-//   - Ethereum consensus API requests can be handled by grpc-gateway correctly
-//   - gRPC responses can be returned as spec-compliant Ethereum consensus API responses
-type ApiProxyMiddleware struct {
-	GatewayAddress  string
-	EndpointCreator EndpointFactory
-	Timeout         time.Duration
-	router          *mux.Router
-}
-
-// EndpointFactory is responsible for creating new instances of Endpoint values.
-type EndpointFactory interface {
-	Create(path string) (*Endpoint, error)
-	Paths() []string
-	IsNil() bool
-}
-
-// Endpoint is a representation of an API HTTP endpoint that should be proxied by the middleware.
-type Endpoint struct {
-	Path               string          // The path of the HTTP endpoint.
-	GetResponse        interface{}     // The struct corresponding to the JSON structure used in a GET response.
-	PostRequest        interface{}     // The struct corresponding to the JSON structure used in a POST request.
-	PostResponse       interface{}     // The struct corresponding to the JSON structure used in a POST response.
-	DeleteRequest      interface{}     // The struct corresponding to the JSON structure used in a DELETE request.
-	DeleteResponse     interface{}     // The struct corresponding to the JSON structure used in a DELETE response.
-	RequestURLLiterals []string        // Names of URL parameters that should not be base64-encoded.
-	RequestQueryParams []QueryParam    // Query parameters of the request.
-	Err                ErrorJson       // The struct corresponding to the error that should be returned in case of a request failure.
-	Hooks              HookCollection  // A collection of functions that can be invoked at various stages of the request/response cycle.
-	CustomHandlers     []CustomHandler // Functions that will be executed instead of the default request/response behaviour.
-}
-
-// RunDefault expresses whether the default processing logic should be carried out after running a pre hook.
-type RunDefault bool
-
-// DefaultEndpoint returns an Endpoint with default configuration, e.g. DefaultErrorJson for error handling.
-func DefaultEndpoint() Endpoint {
-	return Endpoint{
-		Err: &DefaultErrorJson{},
-	}
-}
-
-// QueryParam represents a single query parameter's metadata.
-type QueryParam struct {
-	Name string
-	Hex  bool
-	Enum bool
-}
-
-// CustomHandler is a function that can be invoked at the very beginning of the request,
-// essentially replacing the whole default request/response logic with custom logic for a specific endpoint.
-type CustomHandler = func(m *ApiProxyMiddleware, endpoint Endpoint, w http.ResponseWriter, req *http.Request) (handled bool)
-
-// HookCollection contains hooks that can be used to amend the default request/response cycle with custom logic for a specific endpoint.
-type HookCollection struct {
-	OnPreDeserializeRequestBodyIntoContainer      func(endpoint *Endpoint, w http.ResponseWriter, req *http.Request) (RunDefault, ErrorJson)
-	OnPostDeserializeRequestBodyIntoContainer     func(endpoint *Endpoint, w http.ResponseWriter, req *http.Request) ErrorJson
-	OnPreDeserializeGrpcResponseBodyIntoContainer func([]byte, interface{}) (RunDefault, ErrorJson)
-	OnPreSerializeMiddlewareResponseIntoJson      func(interface{}) (RunDefault, []byte, ErrorJson)
-}
-
-// fieldProcessor applies the processing function f to a value when the tag is present on the field.
-type fieldProcessor struct {
-	tag string
-	f   func(value reflect.Value) error
-}
-
-// Run starts the proxy, registering all proxy endpoints.
-func (m *ApiProxyMiddleware) Run(gatewayRouter *mux.Router) {
-	for _, path := range m.EndpointCreator.Paths() {
-		gatewayRouter.HandleFunc(path, m.WithMiddleware(path))
-	}
-	m.router = gatewayRouter
-}
-
-// ServeHTTP for the proxy middleware.
-func (m *ApiProxyMiddleware) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	m.router.ServeHTTP(w, req)
-}
-
-// WithMiddleware wraps the given endpoint handler with the middleware logic.
-func (m *ApiProxyMiddleware) WithMiddleware(path string) http.HandlerFunc {
-	return func(w http.ResponseWriter, req *http.Request) {
-		endpoint, err := m.EndpointCreator.Create(path)
-		if err != nil {
-			log.WithError(err).Errorf("Could not create endpoint for path: %s", path)
-			return
-		}
-
-		for _, handler := range endpoint.CustomHandlers {
-			if handler(m, *endpoint, w, req) {
-				return
-			}
-		}
-
-		if req.Method == "POST" {
-			if errJson := handlePostRequestForEndpoint(endpoint, w, req); errJson != nil {
-				WriteError(w, errJson, nil)
-				return
-			}
-		}
-
-		if req.Method == "DELETE" {
-			if errJson := handleDeleteRequestForEndpoint(endpoint, req); errJson != nil {
-				WriteError(w, errJson, nil)
-				return
-			}
-		}
-
-		if errJson := m.PrepareRequestForProxying(*endpoint, req); errJson != nil {
-			WriteError(w, errJson, nil)
-			return
-		}
-		grpcResp, errJson := m.ProxyRequest(req)
-		if errJson != nil {
-			WriteError(w, errJson, nil)
-			return
-		}
-		grpcRespBody, errJson := ReadGrpcResponseBody(grpcResp.Body)
-		if errJson != nil {
-			WriteError(w, errJson, nil)
-			return
-		}
-
-		var respJson []byte
-		if !GrpcResponseIsEmpty(grpcRespBody) {
-			respHasError, errJson := HandleGrpcResponseError(endpoint.Err, grpcResp, grpcRespBody, w)
-			if errJson != nil {
-				WriteError(w, errJson, nil)
-				return
-			}
-			if respHasError {
-				return
-			}
-
-			var resp interface{}
-			if req.Method == "GET" {
-				resp = endpoint.GetResponse
-			} else if req.Method == "DELETE" {
-				resp = endpoint.DeleteResponse
-			} else {
-				resp = endpoint.PostResponse
-			}
-			if errJson := deserializeGrpcResponseBodyIntoContainerWrapped(endpoint, grpcRespBody, resp); errJson != nil {
-				WriteError(w, errJson, nil)
-				return
-			}
-			if errJson := ProcessMiddlewareResponseFields(resp); errJson != nil {
-				WriteError(w, errJson, nil)
-				return
-			}
-
-			respJson, errJson = serializeMiddlewareResponseIntoJsonWrapped(endpoint, respJson, resp)
-			if errJson != nil {
-				WriteError(w, errJson, nil)
-				return
-			}
-		}
-
-		if errJson := WriteMiddlewareResponseHeadersAndBody(grpcResp, respJson, w); errJson != nil {
-			WriteError(w, errJson, nil)
-			return
-		}
-		if errJson := Cleanup(grpcResp.Body); errJson != nil {
-			WriteError(w, errJson, nil)
-			return
-		}
-	}
-}
-
-func handlePostRequestForEndpoint(endpoint *Endpoint, w http.ResponseWriter, req *http.Request) ErrorJson {
-	if errJson := deserializeRequestBodyIntoContainerWrapped(endpoint, req, w); errJson != nil {
-		return errJson
-	}
-	if errJson := ProcessRequestContainerFields(endpoint.PostRequest); errJson != nil {
-		return errJson
-	}
-	return SetRequestBodyToRequestContainer(endpoint.PostRequest, req)
-}
-
-func handleDeleteRequestForEndpoint(endpoint *Endpoint, req *http.Request) ErrorJson {
-	if errJson := DeserializeRequestBodyIntoContainer(req.Body, endpoint.DeleteRequest); errJson != nil {
-		return errJson
-	}
-	if errJson := ProcessRequestContainerFields(endpoint.DeleteRequest); errJson != nil {
-		return errJson
-	}
-	return SetRequestBodyToRequestContainer(endpoint.DeleteRequest, req)
-}
-
-func deserializeRequestBodyIntoContainerWrapped(endpoint *Endpoint, req *http.Request, w http.ResponseWriter) ErrorJson {
-	runDefault := true
-	if endpoint.Hooks.OnPreDeserializeRequestBodyIntoContainer != nil {
-		run, errJson := endpoint.Hooks.OnPreDeserializeRequestBodyIntoContainer(endpoint, w, req)
-		if errJson != nil {
-			return errJson
-		}
-		if !run {
-			runDefault = false
-		}
-	}
-	if runDefault {
-		if errJson := DeserializeRequestBodyIntoContainer(req.Body, endpoint.PostRequest); errJson != nil {
-			return errJson
-		}
-	}
-	if endpoint.Hooks.OnPostDeserializeRequestBodyIntoContainer != nil {
-		if errJson := endpoint.Hooks.OnPostDeserializeRequestBodyIntoContainer(endpoint, w, req); errJson != nil {
-			return errJson
-		}
-	}
-	return nil
-}
-
-func deserializeGrpcResponseBodyIntoContainerWrapped(endpoint *Endpoint, grpcResponseBody []byte, resp interface{}) ErrorJson {
-	runDefault := true
-	if endpoint.Hooks.OnPreDeserializeGrpcResponseBodyIntoContainer != nil {
-		run, errJson := endpoint.Hooks.OnPreDeserializeGrpcResponseBodyIntoContainer(grpcResponseBody, resp)
-		if errJson != nil {
-			return errJson
-		}
-		if !run {
-			runDefault = false
-		}
-	}
-	if runDefault {
-		if errJson := DeserializeGrpcResponseBodyIntoContainer(grpcResponseBody, resp); errJson != nil {
-			return errJson
-		}
-	}
-	return nil
-}
-
-func serializeMiddlewareResponseIntoJsonWrapped(endpoint *Endpoint, respJson []byte, resp interface{}) ([]byte, ErrorJson) {
-	runDefault := true
-	var errJson ErrorJson
-	if endpoint.Hooks.OnPreSerializeMiddlewareResponseIntoJson != nil {
-		var run RunDefault
-		run, respJson, errJson = endpoint.Hooks.OnPreSerializeMiddlewareResponseIntoJson(resp)
-		if errJson != nil {
-			return nil, errJson
-		}
-		if !run {
-			runDefault = false
-		}
-	}
-	if runDefault {
-		respJson, errJson = SerializeMiddlewareResponseIntoJson(resp)
-		if errJson != nil {
-			return nil, errJson
-		}
-	}
-	return respJson, nil
-}
--- a/api/gateway/apimiddleware/log.go
+++ b/api/gateway/apimiddleware/log.go
@@ -1,5 +0,0 @@
-package apimiddleware
-
-import "github.com/sirupsen/logrus"
-
-var log = logrus.WithField("prefix", "apimiddleware")
--- a/api/gateway/apimiddleware/param_handling.go
+++ b/api/gateway/apimiddleware/param_handling.go
@@ -1,103 +0,0 @@
-package apimiddleware
-
-import (
-	"encoding/base64"
-	"net/http"
-	"net/url"
-	"strings"
-
-	"github.com/gorilla/mux"
-	butil "github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	"github.com/wealdtech/go-bytesutil"
-)
-
-// HandleURLParameters processes URL parameters, allowing parameterized URLs to be safely and correctly proxied to grpc-gateway.
-func HandleURLParameters(url string, req *http.Request, literals []string) ErrorJson {
-	segments := strings.Split(url, "/")
-
-segmentsLoop:
-	for i, s := range segments {
-		// We only care about segments which are parameterized.
-		if isRequestParam(s) {
-			// Don't do anything with parameters which should be forwarded literally to gRPC.
-			for _, l := range literals {
-				if s == "{"+l+"}" {
-					continue segmentsLoop
-				}
-			}
-
-			routeVar := mux.Vars(req)[s[1:len(s)-1]]
-			bRouteVar := []byte(routeVar)
-			if butil.IsHex(bRouteVar) {
-				var err error
-				bRouteVar, err = bytesutil.FromHexString(string(bRouteVar))
-				if err != nil {
-					return InternalServerErrorWithMessage(err, "could not process URL parameter")
-				}
-			}
-			// Converting hex to base64 may result in a value which malforms the URL.
-			// We use URLEncoding to safely escape such values.
-			base64RouteVar := base64.URLEncoding.EncodeToString(bRouteVar)
-
-			// Merge segments back into the full URL.
-			splitPath := strings.Split(req.URL.Path, "/")
-			splitPath[i] = base64RouteVar
-			req.URL.Path = strings.Join(splitPath, "/")
-		}
-	}
-	return nil
-}
-
-// HandleQueryParameters processes query parameters, allowing them to be safely and correctly proxied to grpc-gateway.
-func HandleQueryParameters(req *http.Request, params []QueryParam) ErrorJson {
-	queryParams := req.URL.Query()
-
-	normalizeQueryValues(queryParams)
-
-	for key, vals := range queryParams {
-		for _, p := range params {
-			if key == p.Name {
-				if p.Hex {
-					queryParams.Del(key)
-					for _, v := range vals {
-						b := []byte(v)
-						if butil.IsHex(b) {
-							var err error
-							b, err = bytesutil.FromHexString(v)
-							if err != nil {
-								return InternalServerErrorWithMessage(err, "could not process query parameter")
-							}
-						}
-						queryParams.Add(key, base64.URLEncoding.EncodeToString(b))
-					}
-				}
-				if p.Enum {
-					queryParams.Del(key)
-					for _, v := range vals {
-						// gRPC expects uppercase enum values.
-						queryParams.Add(key, strings.ToUpper(v))
-					}
-				}
-			}
-		}
-	}
-	req.URL.RawQuery = queryParams.Encode()
-	return nil
-}
-
-// isRequestParam verifies whether the passed string is a request parameter.
-// Request parameters are enclosed in { and }.
-func isRequestParam(s string) bool {
-	return len(s) > 2 && s[0] == '{' && s[len(s)-1] == '}'
-}
-
-func normalizeQueryValues(queryParams url.Values) {
-	// Replace comma-separated values with individual values.
-	for key, vals := range queryParams {
-		splitVals := make([]string, 0)
-		for _, v := range vals {
-			splitVals = append(splitVals, strings.Split(v, ",")...)
-		}
-		queryParams[key] = splitVals
-	}
-}
--- a/api/gateway/apimiddleware/param_handling_test.go
+++ b/api/gateway/apimiddleware/param_handling_test.go
@@ -1,124 +0,0 @@
-package apimiddleware
-
-import (
-	"bytes"
-	"net/http/httptest"
-	"testing"
-
-	"github.com/gorilla/mux"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-func TestHandleURLParameters(t *testing.T) {
-	var body bytes.Buffer
-
-	t.Run("no_params", func(t *testing.T) {
-		request := httptest.NewRequest("GET", "http://foo.example/bar", &body)
-
-		errJson := HandleURLParameters("/not_param", request, []string{})
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "/bar", request.URL.Path)
-	})
-
-	t.Run("with_params", func(t *testing.T) {
-		muxVars := make(map[string]string)
-		muxVars["bar_param"] = "bar"
-		muxVars["quux_param"] = "quux"
-		request := httptest.NewRequest("GET", "http://foo.example/bar/baz/quux", &body)
-		request = mux.SetURLVars(request, muxVars)
-
-		errJson := HandleURLParameters("/{bar_param}/not_param/{quux_param}", request, []string{})
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "/YmFy/baz/cXV1eA==", request.URL.Path)
-	})
-
-	t.Run("with_literal", func(t *testing.T) {
-		muxVars := make(map[string]string)
-		muxVars["bar_param"] = "bar"
-		request := httptest.NewRequest("GET", "http://foo.example/bar/baz", &body)
-		request = mux.SetURLVars(request, muxVars)
-
-		errJson := HandleURLParameters("/{bar_param}/not_param/", request, []string{"bar_param"})
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "/bar/baz", request.URL.Path)
-	})
-
-	t.Run("with_hex", func(t *testing.T) {
-		muxVars := make(map[string]string)
-		muxVars["hex_param"] = "0x626172"
-		request := httptest.NewRequest("GET", "http://foo.example/0x626172/baz", &body)
-		request = mux.SetURLVars(request, muxVars)
-
-		errJson := HandleURLParameters("/{hex_param}/not_param/", request, []string{})
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "/YmFy/baz", request.URL.Path)
-	})
-}
-
-func TestHandleQueryParameters(t *testing.T) {
-	var body bytes.Buffer
-
-	t.Run("regular_params", func(t *testing.T) {
-		request := httptest.NewRequest("GET", "http://foo.example?bar=bar&baz=baz", &body)
-
-		errJson := HandleQueryParameters(request, []QueryParam{{Name: "bar"}, {Name: "baz"}})
-		require.Equal(t, true, errJson == nil)
-		query := request.URL.Query()
-		v, ok := query["bar"]
-		require.Equal(t, true, ok, "query param not found")
-		require.Equal(t, 1, len(v), "wrong number of query param values")
-		assert.Equal(t, "bar", v[0])
-		v, ok = query["baz"]
-		require.Equal(t, true, ok, "query param not found")
-		require.Equal(t, 1, len(v), "wrong number of query param values")
-		assert.Equal(t, "baz", v[0])
-	})
-
-	t.Run("hex_and_enum_params", func(t *testing.T) {
-		request := httptest.NewRequest("GET", "http://foo.example?hex=0x626172&baz=baz", &body)
-
-		errJson := HandleQueryParameters(request, []QueryParam{{Name: "hex", Hex: true}, {Name: "baz", Enum: true}})
-		require.Equal(t, true, errJson == nil)
-		query := request.URL.Query()
-		v, ok := query["hex"]
-		require.Equal(t, true, ok, "query param not found")
-		require.Equal(t, 1, len(v), "wrong number of query param values")
-		assert.Equal(t, "YmFy", v[0])
-		v, ok = query["baz"]
-		require.Equal(t, true, ok, "query param not found")
-		require.Equal(t, 1, len(v), "wrong number of query param values")
-		assert.Equal(t, "BAZ", v[0])
-	})
-}
-
-func TestIsRequestParam(t *testing.T) {
-	tests := []struct {
-		s string
-		b bool
-	}{
-		{"", false},
-		{"{", false},
-		{"}", false},
-		{"{}", false},
-		{"{x}", true},
-		{"{very_long_parameter_name_with_underscores}", true},
-	}
-	for _, tt := range tests {
-		b := isRequestParam(tt.s)
-		assert.Equal(t, tt.b, b)
-	}
-}
-
-func TestNormalizeQueryValues(t *testing.T) {
-	input := make(map[string][]string)
-	input["key"] = []string{"value1", "value2,value3,value4", "value5"}
-
-	normalizeQueryValues(input)
-	require.Equal(t, 5, len(input["key"]))
-	assert.Equal(t, "value1", input["key"][0])
-	assert.Equal(t, "value2", input["key"][1])
-	assert.Equal(t, "value3", input["key"][2])
-	assert.Equal(t, "value4", input["key"][3])
-	assert.Equal(t, "value5", input["key"][4])
-}
--- a/api/gateway/apimiddleware/process_field.go
+++ b/api/gateway/apimiddleware/process_field.go
@@ -1,108 +0,0 @@
-package apimiddleware
-
-import (
-	"encoding/base64"
-	"fmt"
-	"reflect"
-	"strconv"
-	"strings"
-	"time"
-
-	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/pkg/errors"
-	"github.com/wealdtech/go-bytesutil"
-)
-
-// processField calls each processor function on any field that has the matching tag set.
-// It is a recursive function.
-func processField(s interface{}, processors []fieldProcessor) error {
-	kind := reflect.TypeOf(s).Kind()
-	if kind != reflect.Ptr && kind != reflect.Slice && kind != reflect.Array {
-		return fmt.Errorf("processing fields of kind '%v' is unsupported", kind)
-	}
-
-	t := reflect.TypeOf(s).Elem()
-	v := reflect.Indirect(reflect.ValueOf(s))
-
-	for i := 0; i < t.NumField(); i++ {
-		switch v.Field(i).Kind() {
-		case reflect.Slice:
-			sliceElem := t.Field(i).Type.Elem()
-			kind := sliceElem.Kind()
-			// Recursively process slices to struct pointers.
-			if kind == reflect.Ptr && sliceElem.Elem().Kind() == reflect.Struct {
-				for j := 0; j < v.Field(i).Len(); j++ {
-					if err := processField(v.Field(i).Index(j).Interface(), processors); err != nil {
-						return errors.Wrapf(err, "could not process field '%s'", t.Field(i).Name)
-					}
-				}
-			}
-			// Process each string in string slices.
-			if kind == reflect.String {
-				for _, proc := range processors {
-					_, hasTag := t.Field(i).Tag.Lookup(proc.tag)
-					if hasTag {
-						for j := 0; j < v.Field(i).Len(); j++ {
-							if err := proc.f(v.Field(i).Index(j)); err != nil {
-								return errors.Wrapf(err, "could not process field '%s'", t.Field(i).Name)
-							}
-						}
-					}
-				}
-
-			}
-		// Recursively process struct pointers.
-		case reflect.Ptr:
-			if v.Field(i).Elem().Kind() == reflect.Struct {
-				if err := processField(v.Field(i).Interface(), processors); err != nil {
-					return errors.Wrapf(err, "could not process field '%s'", t.Field(i).Name)
-				}
-			}
-		default:
-			field := t.Field(i)
-			for _, proc := range processors {
-				if _, hasTag := field.Tag.Lookup(proc.tag); hasTag {
-					if err := proc.f(v.Field(i)); err != nil {
-						return errors.Wrapf(err, "could not process field '%s'", t.Field(i).Name)
-					}
-				}
-			}
-		}
-	}
-	return nil
-}
-
-func hexToBase64Processor(v reflect.Value) error {
-	b, err := bytesutil.FromHexString(v.String())
-	if err != nil {
-		return err
-	}
-	v.SetString(base64.StdEncoding.EncodeToString(b))
-	return nil
-}
-
-func base64ToHexProcessor(v reflect.Value) error {
-	if v.String() == "" {
-		return nil
-	}
-	b, err := base64.StdEncoding.DecodeString(v.String())
-	if err != nil {
-		return err
-	}
-	v.SetString(hexutil.Encode(b))
-	return nil
-}
-
-func enumToLowercaseProcessor(v reflect.Value) error {
-	v.SetString(strings.ToLower(v.String()))
-	return nil
-}
-
-func timeToUnixProcessor(v reflect.Value) error {
-	t, err := time.Parse(time.RFC3339, v.String())
-	if err != nil {
-		return err
-	}
-	v.SetString(strconv.FormatUint(uint64(t.Unix()), 10))
-	return nil
-}
--- a/api/gateway/apimiddleware/process_request.go
+++ b/api/gateway/apimiddleware/process_request.go
@@ -1,263 +0,0 @@
-package apimiddleware
-
-import (
-	"bytes"
-	"encoding/json"
-	"io"
-	"io/ioutil"
-	"net"
-	"net/http"
-	"strconv"
-	"strings"
-
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/api/grpc"
-)
-
-// DeserializeRequestBodyIntoContainer deserializes the request's body into an endpoint-specific struct.
-func DeserializeRequestBodyIntoContainer(body io.Reader, requestContainer interface{}) ErrorJson {
-	decoder := json.NewDecoder(body)
-	decoder.DisallowUnknownFields()
-	if err := decoder.Decode(&requestContainer); err != nil {
-		if strings.Contains(err.Error(), "json: unknown field") {
-			e := errors.Wrap(err, "could not decode request body")
-			return &DefaultErrorJson{
-				Message: e.Error(),
-				Code:    http.StatusBadRequest,
-			}
-		}
-		return InternalServerErrorWithMessage(err, "could not decode request body")
-	}
-	return nil
-}
-
-// ProcessRequestContainerFields processes fields of an endpoint-specific container according to field tags.
-func ProcessRequestContainerFields(requestContainer interface{}) ErrorJson {
-	if err := processField(requestContainer, []fieldProcessor{
-		{
-			tag: "hex",
-			f:   hexToBase64Processor,
-		},
-	}); err != nil {
-		return InternalServerErrorWithMessage(err, "could not process request data")
-	}
-	return nil
-}
-
-// SetRequestBodyToRequestContainer makes the endpoint-specific container the new body of the request.
-func SetRequestBodyToRequestContainer(requestContainer interface{}, req *http.Request) ErrorJson {
-	// Serialize the struct, which now includes a base64-encoded value, into JSON.
-	j, err := json.Marshal(requestContainer)
-	if err != nil {
-		return InternalServerErrorWithMessage(err, "could not marshal request")
-	}
-	// Set the body to the new JSON.
-	req.Body = ioutil.NopCloser(bytes.NewReader(j))
-	req.Header.Set("Content-Length", strconv.Itoa(len(j)))
-	req.ContentLength = int64(len(j))
-	return nil
-}
-
-// PrepareRequestForProxying applies additional logic to the request so that it can be correctly proxied to grpc-gateway.
-func (m *ApiProxyMiddleware) PrepareRequestForProxying(endpoint Endpoint, req *http.Request) ErrorJson {
-	req.URL.Scheme = "http"
-	req.URL.Host = m.GatewayAddress
-	req.RequestURI = ""
-	if errJson := HandleURLParameters(endpoint.Path, req, endpoint.RequestURLLiterals); errJson != nil {
-		return errJson
-	}
-	if errJson := HandleQueryParameters(req, endpoint.RequestQueryParams); errJson != nil {
-		return errJson
-	}
-	// We have to add the prefix after handling parameters because adding the prefix changes URL segment indexing.
-	req.URL.Path = "/internal" + req.URL.Path
-	return nil
-}
-
-// ProxyRequest proxies the request to grpc-gateway.
-func (m *ApiProxyMiddleware) ProxyRequest(req *http.Request) (*http.Response, ErrorJson) {
-	// We do not use http.DefaultClient because it does not have any timeout.
-	netClient := &http.Client{Timeout: m.Timeout}
-	grpcResp, err := netClient.Do(req)
-	if err != nil {
-		if err, ok := err.(net.Error); ok && err.Timeout() {
-			return nil, TimeoutError()
-		}
-		return nil, InternalServerErrorWithMessage(err, "could not proxy request")
-	}
-	if grpcResp == nil {
-		return nil, &DefaultErrorJson{Message: "nil response from gRPC-gateway", Code: http.StatusInternalServerError}
-	}
-	return grpcResp, nil
-}
-
-// ReadGrpcResponseBody reads the body from the grpc-gateway's response.
-func ReadGrpcResponseBody(r io.Reader) ([]byte, ErrorJson) {
-	body, err := ioutil.ReadAll(r)
-	if err != nil {
-		return nil, InternalServerErrorWithMessage(err, "could not read response body")
-	}
-	return body, nil
-}
-
-// HandleGrpcResponseError acts on an error that resulted from a grpc-gateway's response.
-func HandleGrpcResponseError(errJson ErrorJson, resp *http.Response, respBody []byte, w http.ResponseWriter) (bool, ErrorJson) {
-	responseHasError := false
-	if err := json.Unmarshal(respBody, errJson); err != nil {
-		return false, InternalServerErrorWithMessage(err, "could not unmarshal error")
-	}
-	if errJson.Msg() != "" {
-		responseHasError = true
-		// Something went wrong, but the request completed, meaning we can write headers and the error message.
-		for h, vs := range resp.Header {
-			for _, v := range vs {
-				w.Header().Set(h, v)
-			}
-		}
-		// Handle gRPC timeout.
-		if resp.StatusCode == http.StatusGatewayTimeout {
-			WriteError(w, TimeoutError(), resp.Header)
-		} else {
-			// Set code to HTTP code because unmarshalled body contained gRPC code.
-			errJson.SetCode(resp.StatusCode)
-			WriteError(w, errJson, resp.Header)
-		}
-	}
-	return responseHasError, nil
-}
-
-// GrpcResponseIsEmpty determines whether the grpc-gateway's response body contains no data.
-func GrpcResponseIsEmpty(grpcResponseBody []byte) bool {
-	return len(grpcResponseBody) == 0 || string(grpcResponseBody) == "{}"
-}
-
-// DeserializeGrpcResponseBodyIntoContainer deserializes the grpc-gateway's response body into an endpoint-specific struct.
-func DeserializeGrpcResponseBodyIntoContainer(body []byte, responseContainer interface{}) ErrorJson {
-	if err := json.Unmarshal(body, &responseContainer); err != nil {
-		return InternalServerErrorWithMessage(err, "could not unmarshal response")
-	}
-	return nil
-}
-
-// ProcessMiddlewareResponseFields processes fields of an endpoint-specific container according to field tags.
-func ProcessMiddlewareResponseFields(responseContainer interface{}) ErrorJson {
-	if err := processField(responseContainer, []fieldProcessor{
-		{
-			tag: "hex",
-			f:   base64ToHexProcessor,
-		},
-		{
-			tag: "enum",
-			f:   enumToLowercaseProcessor,
-		},
-		{
-			tag: "time",
-			f:   timeToUnixProcessor,
-		},
-	}); err != nil {
-		return InternalServerErrorWithMessage(err, "could not process response data")
-	}
-	return nil
-}
-
-// SerializeMiddlewareResponseIntoJson serializes the endpoint-specific response struct into a JSON representation.
-func SerializeMiddlewareResponseIntoJson(responseContainer interface{}) (jsonResponse []byte, errJson ErrorJson) {
-	j, err := json.Marshal(responseContainer)
-	if err != nil {
-		return nil, InternalServerErrorWithMessage(err, "could not marshal response")
-	}
-	return j, nil
-}
-
-// WriteMiddlewareResponseHeadersAndBody populates headers and the body of the final response.
-func WriteMiddlewareResponseHeadersAndBody(grpcResp *http.Response, responseJson []byte, w http.ResponseWriter) ErrorJson {
-	var statusCodeHeader string
-	for h, vs := range grpcResp.Header {
-		// We don't want to expose any gRPC metadata in the HTTP response, so we skip forwarding metadata headers.
-		if strings.HasPrefix(h, "Grpc-Metadata") {
-			if h == "Grpc-Metadata-"+grpc.HttpCodeMetadataKey {
-				statusCodeHeader = vs[0]
-			}
-		} else {
-			for _, v := range vs {
-				w.Header().Set(h, v)
-			}
-		}
-	}
-	if !GrpcResponseIsEmpty(responseJson) {
-		w.Header().Set("Content-Length", strconv.Itoa(len(responseJson)))
-		if statusCodeHeader != "" {
-			code, err := strconv.Atoi(statusCodeHeader)
-			if err != nil {
-				return InternalServerErrorWithMessage(err, "could not parse status code")
-			}
-			w.WriteHeader(code)
-		} else {
-			w.WriteHeader(grpcResp.StatusCode)
-		}
-		if _, err := io.Copy(w, ioutil.NopCloser(bytes.NewReader(responseJson))); err != nil {
-			return InternalServerErrorWithMessage(err, "could not write response message")
-		}
-	} else {
-		w.Header().Set("Content-Length", "0")
-		w.WriteHeader(grpcResp.StatusCode)
-	}
-	return nil
-}
-
-// WriteError writes the error by manipulating headers and the body of the final response.
-func WriteError(w http.ResponseWriter, errJson ErrorJson, responseHeader http.Header) {
-	// Include custom error in the error JSON.
-	hasCustomError := false
-	if responseHeader != nil {
-		customError, ok := responseHeader["Grpc-Metadata-"+grpc.CustomErrorMetadataKey]
-		if ok {
-			hasCustomError = true
-			// Assume header has only one value and read the 0 index.
-			if err := json.Unmarshal([]byte(customError[0]), errJson); err != nil {
-				log.WithError(err).Error("Could not unmarshal custom error message")
-				return
-			}
-		}
-	}
-
-	var j []byte
-	if hasCustomError {
-		var err error
-		j, err = json.Marshal(errJson)
-		if err != nil {
-			log.WithError(err).Error("Could not marshal error message")
-			return
-		}
-	} else {
-		var err error
-		// We marshal the response body into a DefaultErrorJson if the custom error is not present.
-		// This is because the ErrorJson argument is the endpoint's error definition, which may contain custom fields.
-		// In such a scenario marhaling the endpoint's error would populate the resulting JSON
-		// with these fields even if they are not present in the gRPC header.
-		d := &DefaultErrorJson{
-			Message: errJson.Msg(),
-			Code:    errJson.StatusCode(),
-		}
-		j, err = json.Marshal(d)
-		if err != nil {
-			log.WithError(err).Error("Could not marshal error message")
-			return
-		}
-	}
-
-	w.Header().Set("Content-Length", strconv.Itoa(len(j)))
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(errJson.StatusCode())
-	if _, err := io.Copy(w, ioutil.NopCloser(bytes.NewReader(j))); err != nil {
-		log.WithError(err).Error("Could not write error message")
-	}
-}
-
-// Cleanup performs final cleanup on the initial response from grpc-gateway.
-func Cleanup(grpcResponseBody io.ReadCloser) ErrorJson {
-	if err := grpcResponseBody.Close(); err != nil {
-		return InternalServerErrorWithMessage(err, "could not close response body")
-	}
-	return nil
-}
--- a/api/gateway/apimiddleware/process_request_test.go
+++ b/api/gateway/apimiddleware/process_request_test.go
@@ -1,409 +0,0 @@
-package apimiddleware
-
-import (
-	"bytes"
-	"encoding/json"
-	"net/http"
-	"net/http/httptest"
-	"strings"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/api/grpc"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/sirupsen/logrus/hooks/test"
-)
-
-type testRequestContainer struct {
-	TestString    string
-	TestHexString string `hex:"true"`
-}
-
-func defaultRequestContainer() *testRequestContainer {
-	return &testRequestContainer{
-		TestString:    "test string",
-		TestHexString: "0x666F6F", // hex encoding of "foo"
-	}
-}
-
-type testResponseContainer struct {
-	TestString string
-	TestHex    string `hex:"true"`
-	TestEnum   string `enum:"true"`
-	TestTime   string `time:"true"`
-}
-
-func defaultResponseContainer() *testResponseContainer {
-	return &testResponseContainer{
-		TestString: "test string",
-		TestHex:    "Zm9v", // base64 encoding of "foo"
-		TestEnum:   "Test Enum",
-		TestTime:   "2006-01-02T15:04:05Z",
-	}
-}
-
-type testErrorJson struct {
-	Message     string
-	Code        int
-	CustomField string
-}
-
-// StatusCode returns the error's underlying error code.
-func (e *testErrorJson) StatusCode() int {
-	return e.Code
-}
-
-// Msg returns the error's underlying message.
-func (e *testErrorJson) Msg() string {
-	return e.Message
-}
-
-// SetCode sets the error's underlying error code.
-func (e *testErrorJson) SetCode(code int) {
-	e.Code = code
-}
-
-// SetMsg sets the error's underlying message.
-func (e *testErrorJson) SetMsg(msg string) {
-	e.Message = msg
-}
-
-func TestDeserializeRequestBodyIntoContainer(t *testing.T) {
-	t.Run("ok", func(t *testing.T) {
-		var bodyJson bytes.Buffer
-		err := json.NewEncoder(&bodyJson).Encode(defaultRequestContainer())
-		require.NoError(t, err)
-
-		container := &testRequestContainer{}
-		errJson := DeserializeRequestBodyIntoContainer(&bodyJson, container)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "test string", container.TestString)
-	})
-
-	t.Run("error", func(t *testing.T) {
-		var bodyJson bytes.Buffer
-		bodyJson.Write([]byte("foo"))
-		errJson := DeserializeRequestBodyIntoContainer(&bodyJson, &testRequestContainer{})
-		require.NotNil(t, errJson)
-		assert.Equal(t, true, strings.Contains(errJson.Msg(), "could not decode request body"))
-		assert.Equal(t, http.StatusInternalServerError, errJson.StatusCode())
-	})
-
-	t.Run("unknown field", func(t *testing.T) {
-		var bodyJson bytes.Buffer
-		bodyJson.Write([]byte("{\"foo\":\"foo\"}"))
-		errJson := DeserializeRequestBodyIntoContainer(&bodyJson, &testRequestContainer{})
-		require.NotNil(t, errJson)
-		assert.Equal(t, true, strings.Contains(errJson.Msg(), "could not decode request body"))
-		assert.Equal(t, http.StatusBadRequest, errJson.StatusCode())
-	})
-}
-
-func TestProcessRequestContainerFields(t *testing.T) {
-	t.Run("ok", func(t *testing.T) {
-		container := defaultRequestContainer()
-
-		errJson := ProcessRequestContainerFields(container)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "Zm9v", container.TestHexString)
-	})
-
-	t.Run("error", func(t *testing.T) {
-		errJson := ProcessRequestContainerFields("foo")
-		require.NotNil(t, errJson)
-		assert.Equal(t, true, strings.Contains(errJson.Msg(), "could not process request data"))
-		assert.Equal(t, http.StatusInternalServerError, errJson.StatusCode())
-	})
-}
-
-func TestSetRequestBodyToRequestContainer(t *testing.T) {
-	var body bytes.Buffer
-	request := httptest.NewRequest("GET", "http://foo.example", &body)
-
-	errJson := SetRequestBodyToRequestContainer(defaultRequestContainer(), request)
-	require.Equal(t, true, errJson == nil)
-	container := &testRequestContainer{}
-	require.NoError(t, json.NewDecoder(request.Body).Decode(container))
-	assert.Equal(t, "test string", container.TestString)
-	contentLengthHeader, ok := request.Header["Content-Length"]
-	require.Equal(t, true, ok)
-	require.Equal(t, 1, len(contentLengthHeader), "wrong number of header values")
-	assert.Equal(t, "55", contentLengthHeader[0])
-	assert.Equal(t, int64(55), request.ContentLength)
-}
-
-func TestPrepareRequestForProxying(t *testing.T) {
-	middleware := &ApiProxyMiddleware{
-		GatewayAddress: "http://gateway.example",
-	}
-	// We will set some params to make the request more interesting.
-	endpoint := Endpoint{
-		Path:               "/{url_param}",
-		RequestURLLiterals: []string{"url_param"},
-		RequestQueryParams: []QueryParam{{Name: "query_param"}},
-	}
-	var body bytes.Buffer
-	request := httptest.NewRequest("GET", "http://foo.example?query_param=bar", &body)
-
-	errJson := middleware.PrepareRequestForProxying(endpoint, request)
-	require.Equal(t, true, errJson == nil)
-	assert.Equal(t, "http", request.URL.Scheme)
-	assert.Equal(t, middleware.GatewayAddress, request.URL.Host)
-	assert.Equal(t, "", request.RequestURI)
-}
-
-func TestReadGrpcResponseBody(t *testing.T) {
-	var b bytes.Buffer
-	b.Write([]byte("foo"))
-
-	body, jsonErr := ReadGrpcResponseBody(&b)
-	require.Equal(t, true, jsonErr == nil)
-	assert.Equal(t, "foo", string(body))
-}
-
-func TestHandleGrpcResponseError(t *testing.T) {
-	response := &http.Response{
-		StatusCode: 400,
-		Header: http.Header{
-			"Foo": []string{"foo"},
-			"Bar": []string{"bar"},
-		},
-	}
-	writer := httptest.NewRecorder()
-	errJson := &testErrorJson{
-		Message: "foo",
-		Code:    400,
-	}
-	b, err := json.Marshal(errJson)
-	require.NoError(t, err)
-
-	hasError, e := HandleGrpcResponseError(errJson, response, b, writer)
-	require.Equal(t, true, e == nil)
-	assert.Equal(t, true, hasError)
-	v, ok := writer.Header()["Foo"]
-	require.Equal(t, true, ok, "header not found")
-	require.Equal(t, 1, len(v), "wrong number of header values")
-	assert.Equal(t, "foo", v[0])
-	v, ok = writer.Header()["Bar"]
-	require.Equal(t, true, ok, "header not found")
-	require.Equal(t, 1, len(v), "wrong number of header values")
-	assert.Equal(t, "bar", v[0])
-	assert.Equal(t, 400, errJson.StatusCode())
-}
-
-func TestGrpcResponseIsEmpty(t *testing.T) {
-	t.Run("nil", func(t *testing.T) {
-		assert.Equal(t, true, GrpcResponseIsEmpty(nil))
-	})
-	t.Run("empty_slice", func(t *testing.T) {
-		assert.Equal(t, true, GrpcResponseIsEmpty(make([]byte, 0)))
-	})
-	t.Run("empty_brackets", func(t *testing.T) {
-		assert.Equal(t, true, GrpcResponseIsEmpty([]byte("{}")))
-	})
-	t.Run("non_empty", func(t *testing.T) {
-		assert.Equal(t, false, GrpcResponseIsEmpty([]byte("{\"foo\":\"bar\"})")))
-	})
-}
-
-func TestDeserializeGrpcResponseBodyIntoContainer(t *testing.T) {
-	t.Run("ok", func(t *testing.T) {
-		body, err := json.Marshal(defaultRequestContainer())
-		require.NoError(t, err)
-
-		container := &testRequestContainer{}
-		errJson := DeserializeGrpcResponseBodyIntoContainer(body, container)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "test string", container.TestString)
-	})
-
-	t.Run("error", func(t *testing.T) {
-		var bodyJson bytes.Buffer
-		bodyJson.Write([]byte("foo"))
-		errJson := DeserializeGrpcResponseBodyIntoContainer(bodyJson.Bytes(), &testRequestContainer{})
-		require.NotNil(t, errJson)
-		assert.Equal(t, true, strings.Contains(errJson.Msg(), "could not unmarshal response"))
-		assert.Equal(t, http.StatusInternalServerError, errJson.StatusCode())
-	})
-}
-
-func TestProcessMiddlewareResponseFields(t *testing.T) {
-	t.Run("Ok", func(t *testing.T) {
-		container := defaultResponseContainer()
-
-		errJson := ProcessMiddlewareResponseFields(container)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, "0x666f6f", container.TestHex)
-		assert.Equal(t, "test enum", container.TestEnum)
-		assert.Equal(t, "1136214245", container.TestTime)
-	})
-
-	t.Run("error", func(t *testing.T) {
-		errJson := ProcessMiddlewareResponseFields("foo")
-		require.NotNil(t, errJson)
-		assert.Equal(t, true, strings.Contains(errJson.Msg(), "could not process response data"))
-		assert.Equal(t, http.StatusInternalServerError, errJson.StatusCode())
-	})
-}
-
-func TestSerializeMiddlewareResponseIntoJson(t *testing.T) {
-	container := defaultResponseContainer()
-	j, errJson := SerializeMiddlewareResponseIntoJson(container)
-	assert.Equal(t, true, errJson == nil)
-	cToDeserialize := &testResponseContainer{}
-	require.NoError(t, json.Unmarshal(j, cToDeserialize))
-	assert.Equal(t, "test string", cToDeserialize.TestString)
-}
-
-func TestWriteMiddlewareResponseHeadersAndBody(t *testing.T) {
-	t.Run("GET", func(t *testing.T) {
-		response := &http.Response{
-			Header: http.Header{
-				"Foo": []string{"foo"},
-				"Grpc-Metadata-" + grpc.HttpCodeMetadataKey: []string{"204"},
-			},
-		}
-		container := defaultResponseContainer()
-		responseJson, err := json.Marshal(container)
-		require.NoError(t, err)
-		writer := httptest.NewRecorder()
-		writer.Body = &bytes.Buffer{}
-
-		errJson := WriteMiddlewareResponseHeadersAndBody(response, responseJson, writer)
-		require.Equal(t, true, errJson == nil)
-		v, ok := writer.Header()["Foo"]
-		require.Equal(t, true, ok, "header not found")
-		require.Equal(t, 1, len(v), "wrong number of header values")
-		assert.Equal(t, "foo", v[0])
-		v, ok = writer.Header()["Content-Length"]
-		require.Equal(t, true, ok, "header not found")
-		require.Equal(t, 1, len(v), "wrong number of header values")
-		assert.Equal(t, "102", v[0])
-		assert.Equal(t, 204, writer.Code)
-		assert.DeepEqual(t, responseJson, writer.Body.Bytes())
-	})
-
-	t.Run("GET_no_grpc_status_code_header", func(t *testing.T) {
-		response := &http.Response{
-			Header:     http.Header{},
-			StatusCode: 204,
-		}
-		container := defaultResponseContainer()
-		responseJson, err := json.Marshal(container)
-		require.NoError(t, err)
-		writer := httptest.NewRecorder()
-
-		errJson := WriteMiddlewareResponseHeadersAndBody(response, responseJson, writer)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, 204, writer.Code)
-	})
-
-	t.Run("GET_invalid_status_code", func(t *testing.T) {
-		response := &http.Response{
-			Header: http.Header{},
-		}
-
-		// Set invalid status code.
-		response.Header["Grpc-Metadata-"+grpc.HttpCodeMetadataKey] = []string{"invalid"}
-
-		container := defaultResponseContainer()
-		responseJson, err := json.Marshal(container)
-		require.NoError(t, err)
-		writer := httptest.NewRecorder()
-
-		errJson := WriteMiddlewareResponseHeadersAndBody(response, responseJson, writer)
-		require.Equal(t, false, errJson == nil)
-		assert.Equal(t, true, strings.Contains(errJson.Msg(), "could not parse status code"))
-		assert.Equal(t, http.StatusInternalServerError, errJson.StatusCode())
-	})
-
-	t.Run("POST", func(t *testing.T) {
-		response := &http.Response{
-			Header:     http.Header{},
-			StatusCode: 204,
-		}
-		container := defaultResponseContainer()
-		responseJson, err := json.Marshal(container)
-		require.NoError(t, err)
-		writer := httptest.NewRecorder()
-
-		errJson := WriteMiddlewareResponseHeadersAndBody(response, responseJson, writer)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, 204, writer.Code)
-	})
-
-	t.Run("POST_with_response_body", func(t *testing.T) {
-		response := &http.Response{
-			Header:     http.Header{},
-			StatusCode: 204,
-		}
-		container := defaultResponseContainer()
-		responseJson, err := json.Marshal(container)
-		require.NoError(t, err)
-		writer := httptest.NewRecorder()
-		writer.Body = &bytes.Buffer{}
-
-		errJson := WriteMiddlewareResponseHeadersAndBody(response, responseJson, writer)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, 204, writer.Code)
-		assert.DeepEqual(t, responseJson, writer.Body.Bytes())
-	})
-
-	t.Run("POST_with_empty_json_body", func(t *testing.T) {
-		response := &http.Response{
-			Header:     http.Header{},
-			StatusCode: 204,
-		}
-		responseJson, err := json.Marshal(struct{}{})
-		require.NoError(t, err)
-		writer := httptest.NewRecorder()
-		writer.Body = &bytes.Buffer{}
-
-		errJson := WriteMiddlewareResponseHeadersAndBody(response, responseJson, writer)
-		require.Equal(t, true, errJson == nil)
-		assert.Equal(t, 204, writer.Code)
-		assert.DeepEqual(t, []byte(nil), writer.Body.Bytes())
-		assert.Equal(t, "0", writer.Header()["Content-Length"][0])
-	})
-}
-
-func TestWriteError(t *testing.T) {
-	t.Run("ok", func(t *testing.T) {
-		responseHeader := http.Header{
-			"Grpc-Metadata-" + grpc.CustomErrorMetadataKey: []string{"{\"CustomField\":\"bar\"}"},
-		}
-		errJson := &testErrorJson{
-			Message: "foo",
-			Code:    500,
-		}
-		writer := httptest.NewRecorder()
-		writer.Body = &bytes.Buffer{}
-
-		WriteError(writer, errJson, responseHeader)
-		v, ok := writer.Header()["Content-Length"]
-		require.Equal(t, true, ok, "header not found")
-		require.Equal(t, 1, len(v), "wrong number of header values")
-		assert.Equal(t, "48", v[0])
-		v, ok = writer.Header()["Content-Type"]
-		require.Equal(t, true, ok, "header not found")
-		require.Equal(t, 1, len(v), "wrong number of header values")
-		assert.Equal(t, "application/json", v[0])
-		assert.Equal(t, 500, writer.Code)
-		eDeserialize := &testErrorJson{}
-		require.NoError(t, json.Unmarshal(writer.Body.Bytes(), eDeserialize))
-		assert.Equal(t, "foo", eDeserialize.Message)
-		assert.Equal(t, 500, eDeserialize.Code)
-		assert.Equal(t, "bar", eDeserialize.CustomField)
-	})
-
-	t.Run("invalid_custom_error_header", func(t *testing.T) {
-		logHook := test.NewGlobal()
-
-		responseHeader := http.Header{
-			"Grpc-Metadata-" + grpc.CustomErrorMetadataKey: []string{"invalid"},
-		}
-
-		WriteError(httptest.NewRecorder(), &testErrorJson{}, responseHeader)
-		assert.LogsContain(t, logHook, "Could not unmarshal custom error message")
-	})
-}
--- a/api/gateway/apimiddleware/structs.go
+++ b/api/gateway/apimiddleware/structs.go
@@ -1,69 +0,0 @@
-package apimiddleware
-
-import (
-	"net/http"
-
-	"github.com/pkg/errors"
-)
-
-// ---------------
-// Error handling.
-// ---------------
-
-// ErrorJson describes common functionality of all JSON error representations.
-type ErrorJson interface {
-	StatusCode() int
-	SetCode(code int)
-	Msg() string
-	SetMsg(msg string)
-}
-
-// DefaultErrorJson is a JSON representation of a simple error value, containing only a message and an error code.
-type DefaultErrorJson struct {
-	Message string `json:"message"`
-	Code    int    `json:"code"`
-}
-
-// InternalServerErrorWithMessage returns a DefaultErrorJson with 500 code and a custom message.
-func InternalServerErrorWithMessage(err error, message string) *DefaultErrorJson {
-	e := errors.Wrapf(err, message)
-	return &DefaultErrorJson{
-		Message: e.Error(),
-		Code:    http.StatusInternalServerError,
-	}
-}
-
-// InternalServerError returns a DefaultErrorJson with 500 code.
-func InternalServerError(err error) *DefaultErrorJson {
-	return &DefaultErrorJson{
-		Message: err.Error(),
-		Code:    http.StatusInternalServerError,
-	}
-}
-
-func TimeoutError() *DefaultErrorJson {
-	return &DefaultErrorJson{
-		Message: "Request timeout",
-		Code:    http.StatusRequestTimeout,
-	}
-}
-
-// StatusCode returns the error's underlying error code.
-func (e *DefaultErrorJson) StatusCode() int {
-	return e.Code
-}
-
-// Msg returns the error's underlying message.
-func (e *DefaultErrorJson) Msg() string {
-	return e.Message
-}
-
-// SetCode sets the error's underlying error code.
-func (e *DefaultErrorJson) SetCode(code int) {
-	e.Code = code
-}
-
-// SetMsg sets the error's underlying message.
-func (e *DefaultErrorJson) SetMsg(msg string) {
-	e.Message = msg
-}
--- a/api/gateway/gateway.go
+++ b/api/gateway/gateway.go
@@ -1,256 +0,0 @@
-// Package gateway defines a grpc-gateway server that serves HTTP-JSON traffic and acts a proxy between HTTP and gRPC.
-package gateway
-
-import (
-	"context"
-	"fmt"
-	"net"
-	"net/http"
-	"path"
-	"strings"
-	"time"
-
-	"github.com/gorilla/mux"
-	gwruntime "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/api/gateway/apimiddleware"
-	"github.com/prysmaticlabs/prysm/runtime"
-	"github.com/rs/cors"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/connectivity"
-	"google.golang.org/grpc/credentials"
-)
-
-var _ runtime.Service = (*Gateway)(nil)
-
-// PbMux serves grpc-gateway requests for selected patterns using registered protobuf handlers.
-type PbMux struct {
-	Registrations []PbHandlerRegistration // Protobuf registrations to be registered in Mux.
-	Patterns      []string                // URL patterns that will be handled by Mux.
-	Mux           *gwruntime.ServeMux     // The router that will be used for grpc-gateway requests.
-}
-
-// PbHandlerRegistration is a function that registers a protobuf handler.
-type PbHandlerRegistration func(context.Context, *gwruntime.ServeMux, *grpc.ClientConn) error
-
-// MuxHandler is a function that implements the mux handler functionality.
-type MuxHandler func(
-	apiMiddlewareHandler *apimiddleware.ApiProxyMiddleware,
-	h http.HandlerFunc,
-	w http.ResponseWriter,
-	req *http.Request,
-)
-
-// Config parameters for setting up the gateway service.
-type config struct {
-	maxCallRecvMsgSize           uint64
-	remoteCert                   string
-	gatewayAddr                  string
-	remoteAddr                   string
-	allowedOrigins               []string
-	apiMiddlewareEndpointFactory apimiddleware.EndpointFactory
-	muxHandler                   MuxHandler
-	pbHandlers                   []*PbMux
-	router                       *mux.Router
-	timeout                      time.Duration
-}
-
-// Gateway is the gRPC gateway to serve HTTP JSON traffic as a proxy and forward it to the gRPC server.
-type Gateway struct {
-	cfg          *config
-	conn         *grpc.ClientConn
-	server       *http.Server
-	cancel       context.CancelFunc
-	proxy        *apimiddleware.ApiProxyMiddleware
-	ctx          context.Context
-	startFailure error
-}
-
-// New returns a new instance of the Gateway.
-func New(ctx context.Context, opts ...Option) (*Gateway, error) {
-	g := &Gateway{
-		ctx: ctx,
-		cfg: &config{
-			router: mux.NewRouter(),
-		},
-	}
-	for _, opt := range opts {
-		if err := opt(g); err != nil {
-			return nil, err
-		}
-	}
-	return g, nil
-}
-
-// Start the gateway service.
-func (g *Gateway) Start() {
-	ctx, cancel := context.WithCancel(g.ctx)
-	g.cancel = cancel
-
-	conn, err := g.dial(ctx, "tcp", g.cfg.remoteAddr)
-	if err != nil {
-		log.WithError(err).Error("Failed to connect to gRPC server")
-		g.startFailure = err
-		return
-	}
-	g.conn = conn
-
-	for _, h := range g.cfg.pbHandlers {
-		for _, r := range h.Registrations {
-			if err := r(ctx, h.Mux, g.conn); err != nil {
-				log.WithError(err).Error("Failed to register handler")
-				g.startFailure = err
-				return
-			}
-		}
-		for _, p := range h.Patterns {
-			g.cfg.router.PathPrefix(p).Handler(h.Mux)
-		}
-	}
-
-	corsMux := g.corsMiddleware(g.cfg.router)
-
-	if g.cfg.apiMiddlewareEndpointFactory != nil && !g.cfg.apiMiddlewareEndpointFactory.IsNil() {
-		g.registerApiMiddleware()
-	}
-
-	if g.cfg.muxHandler != nil {
-		g.cfg.router.PathPrefix("/").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			g.cfg.muxHandler(g.proxy, corsMux.ServeHTTP, w, r)
-		})
-	}
-
-	g.server = &http.Server{
-		Addr:    g.cfg.gatewayAddr,
-		Handler: corsMux,
-	}
-
-	go func() {
-		log.WithField("address", g.cfg.gatewayAddr).Info("Starting gRPC gateway")
-		if err := g.server.ListenAndServe(); err != http.ErrServerClosed {
-			log.WithError(err).Error("Failed to start gRPC gateway")
-			g.startFailure = err
-			return
-		}
-	}()
-}
-
-// Status of grpc gateway. Returns an error if this service is unhealthy.
-func (g *Gateway) Status() error {
-	if g.startFailure != nil {
-		return g.startFailure
-	}
-	if s := g.conn.GetState(); s != connectivity.Ready {
-		return fmt.Errorf("grpc server is %s", s)
-	}
-	return nil
-}
-
-// Stop the gateway with a graceful shutdown.
-func (g *Gateway) Stop() error {
-	if g.server != nil {
-		shutdownCtx, shutdownCancel := context.WithTimeout(g.ctx, 2*time.Second)
-		defer shutdownCancel()
-		if err := g.server.Shutdown(shutdownCtx); err != nil {
-			if errors.Is(err, context.DeadlineExceeded) {
-				log.Warn("Existing connections terminated")
-			} else {
-				log.WithError(err).Error("Failed to gracefully shut down server")
-			}
-		}
-	}
-	if g.cancel != nil {
-		g.cancel()
-	}
-	return nil
-}
-
-func (g *Gateway) corsMiddleware(h http.Handler) http.Handler {
-	c := cors.New(cors.Options{
-		AllowedOrigins:   g.cfg.allowedOrigins,
-		AllowedMethods:   []string{http.MethodPost, http.MethodGet, http.MethodDelete, http.MethodOptions},
-		AllowCredentials: true,
-		MaxAge:           600,
-		AllowedHeaders:   []string{"*"},
-	})
-	return c.Handler(h)
-}
-
-const swaggerDir = "proto/prysm/v1alpha1/"
-
-// SwaggerServer returns swagger specification files located under "/swagger/"
-func SwaggerServer() http.HandlerFunc {
-	return func(w http.ResponseWriter, r *http.Request) {
-		if !strings.HasSuffix(r.URL.Path, ".swagger.json") {
-			log.Debugf("Not found: %s", r.URL.Path)
-			http.NotFound(w, r)
-			return
-		}
-
-		log.Debugf("Serving %s\n", r.URL.Path)
-		p := strings.TrimPrefix(r.URL.Path, "/swagger/")
-		p = path.Join(swaggerDir, p)
-		http.ServeFile(w, r, p)
-	}
-}
-
-// dial the gRPC server.
-func (g *Gateway) dial(ctx context.Context, network, addr string) (*grpc.ClientConn, error) {
-	switch network {
-	case "tcp":
-		return g.dialTCP(ctx, addr)
-	case "unix":
-		return g.dialUnix(ctx, addr)
-	default:
-		return nil, fmt.Errorf("unsupported network type %q", network)
-	}
-}
-
-// dialTCP creates a client connection via TCP.
-// "addr" must be a valid TCP address with a port number.
-func (g *Gateway) dialTCP(ctx context.Context, addr string) (*grpc.ClientConn, error) {
-	security := grpc.WithInsecure()
-	if len(g.cfg.remoteCert) > 0 {
-		creds, err := credentials.NewClientTLSFromFile(g.cfg.remoteCert, "")
-		if err != nil {
-			return nil, err
-		}
-		security = grpc.WithTransportCredentials(creds)
-	}
-	opts := []grpc.DialOption{
-		security,
-		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(int(g.cfg.maxCallRecvMsgSize))),
-	}
-
-	return grpc.DialContext(ctx, addr, opts...)
-}
-
-// dialUnix creates a client connection via a unix domain socket.
-// "addr" must be a valid path to the socket.
-func (g *Gateway) dialUnix(ctx context.Context, addr string) (*grpc.ClientConn, error) {
-	d := func(addr string, timeout time.Duration) (net.Conn, error) {
-		return net.DialTimeout("unix", addr, timeout)
-	}
-	f := func(ctx context.Context, addr string) (net.Conn, error) {
-		if deadline, ok := ctx.Deadline(); ok {
-			return d(addr, time.Until(deadline))
-		}
-		return d(addr, 0)
-	}
-	opts := []grpc.DialOption{
-		grpc.WithInsecure(),
-		grpc.WithContextDialer(f),
-		grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(int(g.cfg.maxCallRecvMsgSize))),
-	}
-	return grpc.DialContext(ctx, addr, opts...)
-}
-
-func (g *Gateway) registerApiMiddleware() {
-	g.proxy = &apimiddleware.ApiProxyMiddleware{
-		GatewayAddress:  g.cfg.gatewayAddr,
-		EndpointCreator: g.cfg.apiMiddlewareEndpointFactory,
-		Timeout:         g.cfg.timeout,
-	}
-	log.Info("Starting API middleware")
-	g.proxy.Run(g.cfg.router)
-}
--- a/api/gateway/gateway_test.go
+++ b/api/gateway/gateway_test.go
@@ -1,128 +0,0 @@
-package gateway
-
-import (
-	"context"
-	"flag"
-	"fmt"
-	"net/http"
-	"net/http/httptest"
-	"net/url"
-	"testing"
-
-	"github.com/gorilla/mux"
-	"github.com/prysmaticlabs/prysm/api/gateway/apimiddleware"
-	"github.com/prysmaticlabs/prysm/cmd/beacon-chain/flags"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	logTest "github.com/sirupsen/logrus/hooks/test"
-	"github.com/urfave/cli/v2"
-)
-
-type mockEndpointFactory struct {
-}
-
-func (*mockEndpointFactory) Paths() []string {
-	return []string{}
-}
-
-func (*mockEndpointFactory) Create(_ string) (*apimiddleware.Endpoint, error) {
-	return nil, nil
-}
-
-func (*mockEndpointFactory) IsNil() bool {
-	return false
-}
-
-func TestGateway_Customized(t *testing.T) {
-	r := mux.NewRouter()
-	cert := "cert"
-	origins := []string{"origin"}
-	size := uint64(100)
-	endpointFactory := &mockEndpointFactory{}
-
-	opts := []Option{
-		WithRouter(r),
-		WithRemoteCert(cert),
-		WithAllowedOrigins(origins),
-		WithMaxCallRecvMsgSize(size),
-		WithApiMiddleware(endpointFactory),
-		WithMuxHandler(func(
-			_ *apimiddleware.ApiProxyMiddleware,
-			_ http.HandlerFunc,
-			_ http.ResponseWriter,
-			_ *http.Request,
-		) {
-		}),
-	}
-
-	g, err := New(context.Background(), opts...)
-	require.NoError(t, err)
-
-	assert.Equal(t, r, g.cfg.router)
-	assert.Equal(t, cert, g.cfg.remoteCert)
-	require.Equal(t, 1, len(g.cfg.allowedOrigins))
-	assert.Equal(t, origins[0], g.cfg.allowedOrigins[0])
-	assert.Equal(t, size, g.cfg.maxCallRecvMsgSize)
-	assert.Equal(t, endpointFactory, g.cfg.apiMiddlewareEndpointFactory)
-}
-
-func TestGateway_StartStop(t *testing.T) {
-	hook := logTest.NewGlobal()
-
-	app := cli.App{}
-	set := flag.NewFlagSet("test", 0)
-	ctx := cli.NewContext(&app, set, nil)
-
-	gatewayPort := ctx.Int(flags.GRPCGatewayPort.Name)
-	gatewayHost := ctx.String(flags.GRPCGatewayHost.Name)
-	rpcHost := ctx.String(flags.RPCHost.Name)
-	selfAddress := fmt.Sprintf("%s:%d", rpcHost, ctx.Int(flags.RPCPort.Name))
-	gatewayAddress := fmt.Sprintf("%s:%d", gatewayHost, gatewayPort)
-
-	opts := []Option{
-		WithGatewayAddr(gatewayAddress),
-		WithRemoteAddr(selfAddress),
-		WithMuxHandler(func(
-			_ *apimiddleware.ApiProxyMiddleware,
-			_ http.HandlerFunc,
-			_ http.ResponseWriter,
-			_ *http.Request,
-		) {
-		}),
-	}
-
-	g, err := New(context.Background(), opts...)
-	require.NoError(t, err)
-
-	g.Start()
-	go func() {
-		require.LogsContain(t, hook, "Starting gRPC gateway")
-		require.LogsDoNotContain(t, hook, "Starting API middleware")
-	}()
-	err = g.Stop()
-	require.NoError(t, err)
-}
-
-func TestGateway_NilHandler_NotFoundHandlerRegistered(t *testing.T) {
-	app := cli.App{}
-	set := flag.NewFlagSet("test", 0)
-	ctx := cli.NewContext(&app, set, nil)
-
-	gatewayPort := ctx.Int(flags.GRPCGatewayPort.Name)
-	gatewayHost := ctx.String(flags.GRPCGatewayHost.Name)
-	rpcHost := ctx.String(flags.RPCHost.Name)
-	selfAddress := fmt.Sprintf("%s:%d", rpcHost, ctx.Int(flags.RPCPort.Name))
-	gatewayAddress := fmt.Sprintf("%s:%d", gatewayHost, gatewayPort)
-
-	opts := []Option{
-		WithGatewayAddr(gatewayAddress),
-		WithRemoteAddr(selfAddress),
-	}
-
-	g, err := New(context.Background(), opts...)
-	require.NoError(t, err)
-
-	writer := httptest.NewRecorder()
-	g.cfg.router.ServeHTTP(writer, &http.Request{Method: "GET", Host: "localhost", URL: &url.URL{Path: "/foo"}})
-	assert.Equal(t, http.StatusNotFound, writer.Code)
-}
--- a/api/gateway/options.go
+++ b/api/gateway/options.go
@@ -1,93 +0,0 @@
-package gateway
-
-import (
-	"time"
-
-	"github.com/gorilla/mux"
-	gwruntime "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/prysmaticlabs/prysm/api/gateway/apimiddleware"
-)
-
-type Option func(g *Gateway) error
-
-func (g *Gateway) SetRouter(r *mux.Router) *Gateway {
-	g.cfg.router = r
-	return g
-}
-
-func WithPbHandlers(handlers []*PbMux) Option {
-	return func(g *Gateway) error {
-		g.cfg.pbHandlers = handlers
-		return nil
-	}
-}
-
-func WithMuxHandler(m MuxHandler) Option {
-	return func(g *Gateway) error {
-		g.cfg.muxHandler = m
-		return nil
-	}
-}
-
-func WithGatewayAddr(addr string) Option {
-	return func(g *Gateway) error {
-		g.cfg.gatewayAddr = addr
-		return nil
-	}
-}
-
-func WithRemoteAddr(addr string) Option {
-	return func(g *Gateway) error {
-		g.cfg.remoteAddr = addr
-		return nil
-	}
-}
-
-// WithRouter allows adding a custom mux router to the gateway.
-func WithRouter(r *mux.Router) Option {
-	return func(g *Gateway) error {
-		g.cfg.router = r
-		return nil
-	}
-}
-
-// WithAllowedOrigins allows adding a set of allowed origins to the gateway.
-func WithAllowedOrigins(origins []string) Option {
-	return func(g *Gateway) error {
-		g.cfg.allowedOrigins = origins
-		return nil
-	}
-}
-
-// WithRemoteCert allows adding a custom certificate to the gateway,
-func WithRemoteCert(cert string) Option {
-	return func(g *Gateway) error {
-		g.cfg.remoteCert = cert
-		return nil
-	}
-}
-
-// WithMaxCallRecvMsgSize allows specifying the maximum allowed gRPC message size.
-func WithMaxCallRecvMsgSize(size uint64) Option {
-	return func(g *Gateway) error {
-		g.cfg.maxCallRecvMsgSize = size
-		return nil
-	}
-}
-
-// WithApiMiddleware allows adding an API middleware proxy to the gateway.
-func WithApiMiddleware(endpointFactory apimiddleware.EndpointFactory) Option {
-	return func(g *Gateway) error {
-		g.cfg.apiMiddlewareEndpointFactory = endpointFactory
-		return nil
-	}
-}
-
-// WithTimeout allows changing the timeout value for API calls.
-func WithTimeout(seconds uint64) Option {
-	return func(g *Gateway) error {
-		g.cfg.timeout = time.Second * time.Duration(seconds)
-		gwruntime.DefaultContextTimeout = time.Second * time.Duration(seconds)
-		return nil
-	}
-}
--- a/api/grpc/BUILD.bazel
+++ b/api/grpc/BUILD.bazel
@@ -1,30 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "grpcutils.go",
-        "parameters.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/api/grpc",
-    visibility = ["//visibility:public"],
-    deps = [
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@org_golang_google_grpc//:go_default_library",
-        "@org_golang_google_grpc//metadata:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["grpcutils_test.go"],
-    embed = [":go_default_library"],
-    deps = [
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "@com_github_grpc_ecosystem_grpc_gateway_v2//runtime:go_default_library",
-        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
-        "@org_golang_google_grpc//:go_default_library",
-        "@org_golang_google_grpc//metadata:go_default_library",
-    ],
-)
--- a/api/grpc/grpcutils_test.go
+++ b/api/grpc/grpcutils_test.go
@@ -1,78 +0,0 @@
-package grpc
-
-import (
-	"context"
-	"encoding/json"
-	"strings"
-	"testing"
-
-	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	logTest "github.com/sirupsen/logrus/hooks/test"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/metadata"
-)
-
-type customErrorData struct {
-	Message string `json:"message"`
-}
-
-func TestAppendHeaders(t *testing.T) {
-	t.Run("one_header", func(t *testing.T) {
-		ctx := AppendHeaders(context.Background(), []string{"first=value1"})
-		md, ok := metadata.FromOutgoingContext(ctx)
-		require.Equal(t, true, ok, "Failed to read context metadata")
-		require.Equal(t, 1, md.Len(), "MetadataV0 contains wrong number of values")
-		assert.Equal(t, "value1", md.Get("first")[0])
-	})
-
-	t.Run("multiple_headers", func(t *testing.T) {
-		ctx := AppendHeaders(context.Background(), []string{"first=value1", "second=value2"})
-		md, ok := metadata.FromOutgoingContext(ctx)
-		require.Equal(t, true, ok, "Failed to read context metadata")
-		require.Equal(t, 2, md.Len(), "MetadataV0 contains wrong number of values")
-		assert.Equal(t, "value1", md.Get("first")[0])
-		assert.Equal(t, "value2", md.Get("second")[0])
-	})
-
-	t.Run("one_empty_header", func(t *testing.T) {
-		ctx := AppendHeaders(context.Background(), []string{"first=value1", ""})
-		md, ok := metadata.FromOutgoingContext(ctx)
-		require.Equal(t, true, ok, "Failed to read context metadata")
-		require.Equal(t, 1, md.Len(), "MetadataV0 contains wrong number of values")
-		assert.Equal(t, "value1", md.Get("first")[0])
-	})
-
-	t.Run("incorrect_header", func(t *testing.T) {
-		logHook := logTest.NewGlobal()
-		ctx := AppendHeaders(context.Background(), []string{"first=value1", "second"})
-		md, ok := metadata.FromOutgoingContext(ctx)
-		require.Equal(t, true, ok, "Failed to read context metadata")
-		require.Equal(t, 1, md.Len(), "MetadataV0 contains wrong number of values")
-		assert.Equal(t, "value1", md.Get("first")[0])
-		assert.LogsContain(t, logHook, "Skipping second")
-	})
-
-	t.Run("header_value_with_equal_sign", func(t *testing.T) {
-		ctx := AppendHeaders(context.Background(), []string{"first=value=1"})
-		md, ok := metadata.FromOutgoingContext(ctx)
-		require.Equal(t, true, ok, "Failed to read context metadata")
-		require.Equal(t, 1, md.Len(), "MetadataV0 contains wrong number of values")
-		assert.Equal(t, "value=1", md.Get("first")[0])
-	})
-}
-
-func TestAppendCustomErrorHeader(t *testing.T) {
-	stream := &runtime.ServerTransportStream{}
-	ctx := grpc.NewContextWithServerTransportStream(context.Background(), stream)
-	data := &customErrorData{Message: "foo"}
-	require.NoError(t, AppendCustomErrorHeader(ctx, data))
-	// The stream used in test setup sets the metadata key in lowercase.
-	value, ok := stream.Header()[strings.ToLower(CustomErrorMetadataKey)]
-	require.Equal(t, true, ok, "Failed to retrieve custom error metadata value")
-	expected, err := json.Marshal(data)
-	require.NoError(t, err)
-	assert.Equal(t, string(expected), value[0])
-
-}
--- a/api/grpc/parameters.go
+++ b/api/grpc/parameters.go
@@ -1,8 +0,0 @@
-package grpc
-
-// CustomErrorMetadataKey is the name of the metadata key storing additional error information.
-// Metadata value is expected to be a byte-encoded JSON object.
-const CustomErrorMetadataKey = "Custom-Error"
-
-// HttpCodeMetadataKey is the key to use when setting custom HTTP status codes in gRPC metadata.
-const HttpCodeMetadataKey = "X-Http-Code"
--- a/api/pagination/BUILD.bazel
+++ b/api/pagination/BUILD.bazel
@@ -1,22 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = ["pagination.go"],
-    importpath = "github.com/prysmaticlabs/prysm/api/pagination",
-    visibility = ["//visibility:public"],
-    deps = [
-        "//config/params:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["pagination_test.go"],
-    deps = [
-        ":go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-    ],
-)
--- a/async/BUILD.bazel
+++ b/async/BUILD.bazel
@@ -1,33 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "debounce.go",
-        "every.go",
-        "multilock.go",
-        "scatter.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/async",
-    visibility = ["//visibility:public"],
-    deps = ["@com_github_sirupsen_logrus//:go_default_library"],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = [
-        "benchmark_test.go",
-        "debounce_test.go",
-        "every_test.go",
-        "multilock_test.go",
-        "scatter_test.go",
-    ],
-    embed = [":go_default_library"],
-    deps = [
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "//testing/util:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@com_github_stretchr_testify//assert:go_default_library",
-    ],
-)
--- a/async/abool/BUILD.bazel
+++ b/async/abool/BUILD.bazel
@@ -1,14 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = ["abool.go"],
-    importpath = "github.com/prysmaticlabs/prysm/async/abool",
-    visibility = ["//visibility:public"],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["abool_test.go"],
-    embed = [":go_default_library"],
-)
--- a/async/benchmark_test.go
+++ b/async/benchmark_test.go
@@ -1,63 +0,0 @@
-package async_test
-
-import (
-	"crypto/rand"
-	"crypto/sha256"
-	"sync"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/async"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	log "github.com/sirupsen/logrus"
-)
-
-var input [][]byte
-
-const (
-	benchmarkElements    = 65536
-	benchmarkElementSize = 32
-	benchmarkHashRuns    = 128
-)
-
-func init() {
-	input = make([][]byte, benchmarkElements)
-	for i := 0; i < benchmarkElements; i++ {
-		input[i] = make([]byte, benchmarkElementSize)
-		_, err := rand.Read(input[i])
-		if err != nil {
-			log.WithError(err).Debug("Cannot read from rand")
-		}
-	}
-}
-
-// hash repeatedly hashes the data passed to it
-func hash(input [][]byte) [][]byte {
-	output := make([][]byte, len(input))
-	for i := range input {
-		copy(output, input)
-		for j := 0; j < benchmarkHashRuns; j++ {
-			hash := sha256.Sum256(output[i])
-			output[i] = hash[:]
-		}
-	}
-	return output
-}
-
-func BenchmarkHash(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		hash(input)
-	}
-}
-
-func BenchmarkHashMP(b *testing.B) {
-	output := make([][]byte, len(input))
-	for i := 0; i < b.N; i++ {
-		workerResults, err := async.Scatter(len(input), func(offset int, entries int, _ *sync.RWMutex) (interface{}, error) {
-			return hash(input[offset : offset+entries]), nil
-		})
-		require.NoError(b, err)
-		for _, result := range workerResults {
-			copy(output[result.Offset:], result.Extent.([][]byte))
-		}
-	}
-}
--- a/async/event/BUILD.bazel
+++ b/async/event/BUILD.bazel
@@ -1,29 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "feed.go",
-        "subscription.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/async/event",
-    visibility = ["//visibility:public"],
-    deps = ["//time/mclock:go_default_library"],
-)
-
-go_test(
-    name = "go_default_test",
-    size = "small",
-    srcs = [
-        "example_feed_test.go",
-        "example_scope_test.go",
-        "example_subscription_test.go",
-        "feed_test.go",
-        "subscription_test.go",
-    ],
-    embed = [":go_default_library"],
-    deps = [
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-    ],
-)
--- a/async/event/feed_test.go
+++ b/async/event/feed_test.go
@@ -1,507 +0,0 @@
-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-package event
-
-import (
-	"fmt"
-	"reflect"
-	"sync"
-	"testing"
-	"time"
-
-	"github.com/prysmaticlabs/prysm/testing/assert"
-)
-
-func TestFeedPanics(t *testing.T) {
-	{
-		var f Feed
-		f.Send(2)
-		want := feedTypeError{op: "Send", got: reflect.TypeOf(uint64(0)), want: reflect.TypeOf(0)}
-		assert.NoError(t, checkPanic(want, func() { f.Send(uint64(2)) }))
-	}
-	{
-		var f Feed
-		ch := make(chan int)
-		f.Subscribe(ch)
-		want := feedTypeError{op: "Send", got: reflect.TypeOf(uint64(0)), want: reflect.TypeOf(0)}
-		assert.NoError(t, checkPanic(want, func() { f.Send(uint64(2)) }))
-	}
-	{
-		var f Feed
-		f.Send(2)
-		want := feedTypeError{op: "Subscribe", got: reflect.TypeOf(make(chan uint64)), want: reflect.TypeOf(make(chan<- int))}
-		assert.NoError(t, checkPanic(want, func() { f.Subscribe(make(chan uint64)) }))
-	}
-	{
-		var f Feed
-		assert.NoError(t, checkPanic(errBadChannel, func() { f.Subscribe(make(<-chan int)) }))
-	}
-	{
-		var f Feed
-		assert.NoError(t, checkPanic(errBadChannel, func() { f.Subscribe(0) }))
-	}
-}
-
-func checkPanic(want error, fn func()) (err error) {
-	defer func() {
-		panicResult := recover()
-		if panicResult == nil {
-			err = fmt.Errorf("didn't panic")
-		} else if !reflect.DeepEqual(panicResult, want) {
-			err = fmt.Errorf("panicked with wrong error: got %q, want %q", panicResult, want)
-		}
-	}()
-	fn()
-	return nil
-}
-
-func TestFeed(t *testing.T) {
-	var feed Feed
-	var done, subscribed sync.WaitGroup
-	subscriber := func(i int) {
-		defer done.Done()
-
-		subchan := make(chan int)
-		sub := feed.Subscribe(subchan)
-		timeout := time.NewTimer(2 * time.Second)
-		subscribed.Done()
-
-		select {
-		case v := <-subchan:
-			if v != 1 {
-				t.Errorf("%d: received value %d, want 1", i, v)
-			}
-		case <-timeout.C:
-			t.Errorf("%d: receive timeout", i)
-		}
-
-		sub.Unsubscribe()
-		select {
-		case _, ok := <-sub.Err():
-			if ok {
-				t.Errorf("%d: error channel not closed after unsubscribe", i)
-			}
-		case <-timeout.C:
-			t.Errorf("%d: unsubscribe timeout", i)
-		}
-	}
-
-	const n = 1000
-	done.Add(n)
-	subscribed.Add(n)
-	for i := 0; i < n; i++ {
-		go subscriber(i)
-	}
-	subscribed.Wait()
-	if nsent := feed.Send(1); nsent != n {
-		t.Errorf("first send delivered %d times, want %d", nsent, n)
-	}
-	if nsent := feed.Send(2); nsent != 0 {
-		t.Errorf("second send delivered %d times, want 0", nsent)
-	}
-	done.Wait()
-}
-
-func TestFeedSubscribeSameChannel(t *testing.T) {
-	var (
-		feed Feed
-		done sync.WaitGroup
-		ch   = make(chan int)
-		sub1 = feed.Subscribe(ch)
-		sub2 = feed.Subscribe(ch)
-		_    = feed.Subscribe(ch)
-	)
-	expectSends := func(value, n int) {
-		if nsent := feed.Send(value); nsent != n {
-			t.Errorf("send delivered %d times, want %d", nsent, n)
-		}
-		done.Done()
-	}
-	expectRecv := func(wantValue, n int) {
-		for i := 0; i < n; i++ {
-			if v := <-ch; v != wantValue {
-				t.Errorf("received %d, want %d", v, wantValue)
-			}
-		}
-	}
-
-	done.Add(1)
-	go expectSends(1, 3)
-	expectRecv(1, 3)
-	done.Wait()
-
-	sub1.Unsubscribe()
-
-	done.Add(1)
-	go expectSends(2, 2)
-	expectRecv(2, 2)
-	done.Wait()
-
-	sub2.Unsubscribe()
-
-	done.Add(1)
-	go expectSends(3, 1)
-	expectRecv(3, 1)
-	done.Wait()
-}
-
-func TestFeedSubscribeBlockedPost(_ *testing.T) {
-	var (
-		feed   Feed
-		nsends = 2000
-		ch1    = make(chan int)
-		ch2    = make(chan int)
-		wg     sync.WaitGroup
-	)
-	defer wg.Wait()
-
-	feed.Subscribe(ch1)
-	wg.Add(nsends)
-	for i := 0; i < nsends; i++ {
-		go func() {
-			feed.Send(99)
-			wg.Done()
-		}()
-	}
-
-	sub2 := feed.Subscribe(ch2)
-	defer sub2.Unsubscribe()
-
-	// We're done when ch1 has received N times.
-	// The number of receives on ch2 depends on scheduling.
-	for i := 0; i < nsends; {
-		select {
-		case <-ch1:
-			i++
-		case <-ch2:
-		}
-	}
-}
-
-func TestFeedUnsubscribeBlockedPost(_ *testing.T) {
-	var (
-		feed   Feed
-		nsends = 200
-		chans  = make([]chan int, 2000)
-		subs   = make([]Subscription, len(chans))
-		bchan  = make(chan int)
-		bsub   = feed.Subscribe(bchan)
-		wg     sync.WaitGroup
-	)
-	for i := range chans {
-		chans[i] = make(chan int, nsends)
-	}
-
-	// Queue up some Sends. None of these can make progress while bchan isn't read.
-	wg.Add(nsends)
-	for i := 0; i < nsends; i++ {
-		go func() {
-			feed.Send(99)
-			wg.Done()
-		}()
-	}
-	// Subscribe the other channels.
-	for i, ch := range chans {
-		subs[i] = feed.Subscribe(ch)
-	}
-	// Unsubscribe them again.
-	for _, sub := range subs {
-		sub.Unsubscribe()
-	}
-	// Unblock the Sends.
-	bsub.Unsubscribe()
-	wg.Wait()
-}
-
-// Checks that unsubscribing a channel during Send works even if that
-// channel has already been sent on.
-func TestFeedUnsubscribeSentChan(_ *testing.T) {
-	var (
-		feed Feed
-		ch1  = make(chan int)
-		ch2  = make(chan int)
-		sub1 = feed.Subscribe(ch1)
-		sub2 = feed.Subscribe(ch2)
-		wg   sync.WaitGroup
-	)
-	defer sub2.Unsubscribe()
-
-	wg.Add(1)
-	go func() {
-		feed.Send(0)
-		wg.Done()
-	}()
-
-	// Wait for the value on ch1.
-	<-ch1
-	// Unsubscribe ch1, removing it from the send cases.
-	sub1.Unsubscribe()
-
-	// Receive ch2, finishing Send.
-	<-ch2
-	wg.Wait()
-
-	// Send again. This should send to ch2 only, so the wait group will unblock
-	// as soon as a value is received on ch2.
-	wg.Add(1)
-	go func() {
-		feed.Send(0)
-		wg.Done()
-	}()
-	<-ch2
-	wg.Wait()
-}
-
-func TestFeedUnsubscribeFromInbox(t *testing.T) {
-	var (
-		feed Feed
-		ch1  = make(chan int)
-		ch2  = make(chan int)
-		sub1 = feed.Subscribe(ch1)
-		sub2 = feed.Subscribe(ch1)
-		sub3 = feed.Subscribe(ch2)
-	)
-	assert.Equal(t, 3, len(feed.inbox))
-	assert.Equal(t, 1, len(feed.sendCases), "sendCases is non-empty after unsubscribe")
-
-	sub1.Unsubscribe()
-	sub2.Unsubscribe()
-	sub3.Unsubscribe()
-	assert.Equal(t, 0, len(feed.inbox), "Inbox is non-empty after unsubscribe")
-	assert.Equal(t, 1, len(feed.sendCases), "sendCases is non-empty after unsubscribe")
-}
-
-func BenchmarkFeedSend1000(b *testing.B) {
-	var (
-		done  sync.WaitGroup
-		feed  Feed
-		nsubs = 1000
-	)
-	subscriber := func(ch <-chan int) {
-		for i := 0; i < b.N; i++ {
-			<-ch
-		}
-		done.Done()
-	}
-	done.Add(nsubs)
-	for i := 0; i < nsubs; i++ {
-		ch := make(chan int, 200)
-		feed.Subscribe(ch)
-		go subscriber(ch)
-	}
-
-	// The actual benchmark.
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		if feed.Send(i) != nsubs {
-			panic("wrong number of sends")
-		}
-	}
-
-	b.StopTimer()
-	done.Wait()
-}
-
-func TestFeed_Send(t *testing.T) {
-	tests := []struct {
-		name        string
-		evFeed      *Feed
-		testSetup   func(fd *Feed, t *testing.T, o interface{})
-		obj         interface{}
-		expectPanic bool
-	}{
-		{
-			name:   "normal struct",
-			evFeed: new(Feed),
-			testSetup: func(fd *Feed, t *testing.T, o interface{}) {
-				testChan := make(chan testFeedWithPointer, 1)
-				fd.Subscribe(testChan)
-			},
-			obj: testFeedWithPointer{
-				a: new(uint64),
-				b: new(string),
-			},
-			expectPanic: false,
-		},
-		{
-			name:   "un-implemented interface",
-			evFeed: new(Feed),
-			testSetup: func(fd *Feed, t *testing.T, o interface{}) {
-				testChan := make(chan testFeedIface, 1)
-				fd.Subscribe(testChan)
-			},
-			obj: testFeedWithPointer{
-				a: new(uint64),
-				b: new(string),
-			},
-			expectPanic: true,
-		},
-		{
-			name:   "semi-implemented interface",
-			evFeed: new(Feed),
-			testSetup: func(fd *Feed, t *testing.T, o interface{}) {
-				testChan := make(chan testFeedIface, 1)
-				fd.Subscribe(testChan)
-			},
-			obj: testFeed2{
-				a: 0,
-				b: "",
-				c: []byte{'A'},
-			},
-			expectPanic: true,
-		},
-		{
-			name:   "fully-implemented interface",
-			evFeed: new(Feed),
-			testSetup: func(fd *Feed, t *testing.T, o interface{}) {
-				testChan := make(chan testFeedIface)
-				// Make it unbuffered to allow message to
-				// pass through
-				go func() {
-					a := <-testChan
-					if !reflect.DeepEqual(a, o) {
-						t.Errorf("Got = %v, want = %v", a, o)
-					}
-				}()
-				fd.Subscribe(testChan)
-			},
-			obj: testFeed{
-				a: 0,
-				b: "",
-			},
-			expectPanic: false,
-		},
-		{
-			name:   "fully-implemented interface with additional methods",
-			evFeed: new(Feed),
-			testSetup: func(fd *Feed, t *testing.T, o interface{}) {
-				testChan := make(chan testFeedIface)
-				// Make it unbuffered to allow message to
-				// pass through
-				go func() {
-					a := <-testChan
-					if !reflect.DeepEqual(a, o) {
-						t.Errorf("Got = %v, want = %v", a, o)
-					}
-				}()
-				fd.Subscribe(testChan)
-			},
-			obj: testFeed3{
-				a: 0,
-				b: "",
-				c: []byte{'A'},
-				d: []byte{'B'},
-			},
-			expectPanic: false,
-		},
-		{
-			name:   "concrete types implementing the same interface",
-			evFeed: new(Feed),
-			testSetup: func(fd *Feed, t *testing.T, o interface{}) {
-				testChan := make(chan testFeed, 1)
-				// Make it unbuffered to allow message to
-				// pass through
-				go func() {
-					a := <-testChan
-					if !reflect.DeepEqual(a, o) {
-						t.Errorf("Got = %v, want = %v", a, o)
-					}
-				}()
-				fd.Subscribe(testChan)
-			},
-			obj: testFeed3{
-				a: 0,
-				b: "",
-				c: []byte{'A'},
-				d: []byte{'B'},
-			},
-			expectPanic: true,
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			defer func() {
-				if r := recover(); r != nil {
-					if !tt.expectPanic {
-						t.Errorf("panic triggered when unexpected: %v", r)
-					}
-				} else {
-					if tt.expectPanic {
-						t.Error("panic not triggered when expected")
-					}
-				}
-			}()
-			tt.testSetup(tt.evFeed, t, tt.obj)
-			if gotNsent := tt.evFeed.Send(tt.obj); gotNsent != 1 {
-				t.Errorf("Send() = %v, want %v", gotNsent, 1)
-			}
-		})
-	}
-}
-
-// The following objects below are a collection of different
-// struct types to test with.
-type testFeed struct {
-	a uint64
-	b string
-}
-
-func (testFeed) method1() {
-
-}
-
-func (testFeed) method2() {
-
-}
-
-type testFeedWithPointer struct {
-	a *uint64
-	b *string
-}
-
-type testFeed2 struct {
-	a uint64
-	b string
-	c []byte
-}
-
-func (testFeed2) method1() {
-
-}
-
-type testFeed3 struct {
-	a    uint64
-	b    string
-	c, d []byte
-}
-
-func (testFeed3) method1() {
-
-}
-
-func (testFeed3) method2() {
-
-}
-
-func (testFeed3) method3() {
-
-}
-
-type testFeedIface interface {
-	method1()
-	method2()
-}
--- a/beacon-chain/README.md
+++ b/beacon-chain/README.md
@@ -1,9 +1,9 @@
 # Prysmatic Labs Beacon Chain Implementation

-This is the main project folder for the beacon chain implementation of Ethereum written in Go by [Prysmatic Labs](https://prysmaticlabs.com).
+This is the main project folder for the beacon chain implementation of eth2 written in Go by [Prysmatic Labs](https://prysmaticlabs.com).

 You can also read our main [README](https://github.com/prysmaticlabs/prysm/blob/master/README.md) and join our active chat room on Discord.

 [![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/CTYGPUJ)

-Also, read the official beacon chain [specification](https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/beacon-chain.md), this design spec serves as a source of truth for the beacon chain implementation we follow at Prysmatic Labs.
+Also, read the official beacon chain [specification](https://github.com/ethereum/eth2.0-specs/blob/master/specs/phase0/beacon-chain.md), this design spec serves as a source of truth for the beacon chain implementation we follow at Prysmatic Labs.
--- a/beacon-chain/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -1,19 +1,15 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+load("@prysm//tools/go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_test")

 go_library(
    name = "go_default_library",
    srcs = [
        "chain_info.go",
-        "error.go",
        "head.go",
-        "head_sync_committee_info.go",
+        "info.go",
        "init_sync_process_block.go",
        "log.go",
        "metrics.go",
-        "new_slot.go",
-        "optimistic_sync.go",
-        "options.go",
-        "pow_block.go",
        "process_attestation.go",
        "process_attestation_helpers.go",
        "process_block.go",
@@ -21,62 +17,48 @@ go_library(
        "receive_attestation.go",
        "receive_block.go",
        "service.go",
-        "state_balance_cache.go",
        "weak_subjectivity_checks.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/blockchain",
    visibility = [
        "//beacon-chain:__subpackages__",
-        "//cmd/beacon-chain:__subpackages__",
-        "//testing/slasher/simulator:__pkg__",
-        "//testing/spectest:__subpackages__",
+        "//fuzz:__pkg__",
    ],
    deps = [
-        "//async:go_default_library",
-        "//async/event:go_default_library",
-        "//beacon-chain/blockchain/store:go_default_library",
        "//beacon-chain/cache:go_default_library",
        "//beacon-chain/cache/depositcache:go_default_library",
-        "//beacon-chain/core/altair:go_default_library",
-        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/epoch/precompute:go_default_library",
        "//beacon-chain/core/feed:go_default_library",
        "//beacon-chain/core/feed/state:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/signing:go_default_library",
-        "//beacon-chain/core/time:go_default_library",
-        "//beacon-chain/core/transition:go_default_library",
+        "//beacon-chain/core/state:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/db/filters:go_default_library",
        "//beacon-chain/forkchoice:go_default_library",
-        "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
        "//beacon-chain/forkchoice/protoarray:go_default_library",
-        "//beacon-chain/forkchoice/types:go_default_library",
        "//beacon-chain/operations/attestations:go_default_library",
        "//beacon-chain/operations/slashings:go_default_library",
        "//beacon-chain/operations/voluntaryexits:go_default_library",
        "//beacon-chain/p2p:go_default_library",
        "//beacon-chain/powchain:go_default_library",
-        "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
        "//beacon-chain/state/stategen:go_default_library",
        "//cmd/beacon-chain/flags:go_default_library",
-        "//config/features:go_default_library",
-        "//config/fieldparams:go_default_library",
-        "//config/params:go_default_library",
-        "//crypto/bls:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//monitoring/tracing:go_default_library",
-        "//proto/engine/v1:go_default_library",
+        "//proto/beacon/p2p/v1:go_default_library",
        "//proto/eth/v1:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//proto/prysm/v1alpha1/attestation:go_default_library",
-        "//proto/prysm/v1alpha1/block:go_default_library",
-        "//runtime/version:go_default_library",
-        "//time:go_default_library",
-        "//time/slots:go_default_library",
-        "@com_github_ethereum_go_ethereum//common:go_default_library",
-        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
-        "@com_github_holiman_uint256//:go_default_library",
+        "//proto/eth/v1alpha1:go_default_library",
+        "//shared/attestationutil:go_default_library",
+        "//shared/bls:go_default_library",
+        "//shared/bytesutil:go_default_library",
+        "//shared/copyutil:go_default_library",
+        "//shared/featureconfig:go_default_library",
+        "//shared/interfaces:go_default_library",
+        "//shared/mputil:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/slotutil:go_default_library",
+        "//shared/timeutils:go_default_library",
+        "//shared/traceutil:go_default_library",
+        "@com_github_emicklei_dot//:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
@@ -101,14 +83,10 @@ go_test(
        "blockchain_test.go",
        "chain_info_test.go",
        "checktags_test.go",
-        "head_sync_committee_info_test.go",
        "head_test.go",
+        "info_test.go",
        "init_test.go",
-        "log_test.go",
        "metrics_test.go",
-        "mock_test.go",
-        "optimistic_sync_test.go",
-        "pow_block_test.go",
        "process_attestation_test.go",
        "process_block_test.go",
        "receive_attestation_test.go",
@@ -119,27 +97,26 @@ go_test(
    embed = [":go_default_library"],
    gotags = ["develop"],
    deps = [
-        "//async/event:go_default_library",
        "//beacon-chain/blockchain/testing:go_default_library",
        "//beacon-chain/cache/depositcache:go_default_library",
        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/transition:go_default_library",
+        "//beacon-chain/core/state:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/db/testing:go_default_library",
        "//beacon-chain/p2p:go_default_library",
        "//beacon-chain/powchain:go_default_library",
-        "//beacon-chain/powchain/testing:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//beacon-chain/state/stateutil:go_default_library",
-        "//beacon-chain/state/v1:go_default_library",
-        "//config/fieldparams:go_default_library",
-        "//config/params:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//proto/prysm/v1alpha1/wrapper:go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "//testing/util:go_default_library",
+        "//proto/beacon/db:go_default_library",
+        "//proto/beacon/p2p/v1:go_default_library",
+        "//proto/eth/v1alpha1:go_default_library",
+        "//shared/bytesutil:go_default_library",
+        "//shared/event:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/testutil:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
        "@com_github_ethereum_go_ethereum//:go_default_library",
        "@com_github_ethereum_go_ethereum//common:go_default_library",
        "@com_github_ethereum_go_ethereum//core/types:go_default_library",
@@ -157,7 +134,6 @@ go_test(
        "chain_info_norace_test.go",
        "checktags_test.go",
        "init_test.go",
-        "mock_test.go",
        "receive_block_test.go",
        "service_norace_test.go",
    ],
@@ -173,24 +149,23 @@ go_test(
    race = "on",
    tags = ["race_on"],
    deps = [
-        "//async/event:go_default_library",
        "//beacon-chain/blockchain/testing:go_default_library",
        "//beacon-chain/cache/depositcache:go_default_library",
        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/transition:go_default_library",
+        "//beacon-chain/core/state:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/db/testing:go_default_library",
        "//beacon-chain/p2p:go_default_library",
        "//beacon-chain/powchain:go_default_library",
-        "//beacon-chain/powchain/testing:go_default_library",
-        "//config/params:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//proto/prysm/v1alpha1/wrapper:go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "//testing/util:go_default_library",
+        "//proto/beacon/p2p/v1:go_default_library",
+        "//proto/eth/v1alpha1:go_default_library",
+        "//shared/bytesutil:go_default_library",
+        "//shared/event:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/testutil:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
        "@com_github_ethereum_go_ethereum//:go_default_library",
        "@com_github_ethereum_go_ethereum//common:go_default_library",
        "@com_github_ethereum_go_ethereum//core/types:go_default_library",
--- a/beacon-chain/blockchain/chain_info.go
+++ b/beacon-chain/blockchain/chain_info.go
@@ -6,16 +6,14 @@ import (

 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/copyutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
 	"go.opencensus.io/trace"
 )

@@ -26,20 +24,17 @@ type ChainInfoFetcher interface {
 	FinalizationFetcher
 	GenesisFetcher
 	CanonicalFetcher
-	ForkFetcher
-	TimeFetcher
-	HeadDomainFetcher
 }

-// TimeFetcher retrieves the Ethereum consensus data that's related to time.
+// TimeFetcher retrieves the Eth2 data that's related to time.
 type TimeFetcher interface {
 	GenesisTime() time.Time
 	CurrentSlot() types.Slot
 }

-// GenesisFetcher retrieves the Ethereum consensus data related to its genesis.
+// GenesisFetcher retrieves the eth2 data related to its genesis.
 type GenesisFetcher interface {
-	GenesisValidatorsRoot() [32]byte
+	GenesisValidatorRoot() [32]byte
 }

 // HeadFetcher defines a common interface for methods in blockchain service which
@@ -47,25 +42,19 @@ type GenesisFetcher interface {
 type HeadFetcher interface {
 	HeadSlot() types.Slot
 	HeadRoot(ctx context.Context) ([]byte, error)
-	HeadBlock(ctx context.Context) (block.SignedBeaconBlock, error)
-	HeadState(ctx context.Context) (state.BeaconState, error)
+	HeadBlock(ctx context.Context) (interfaces.SignedBeaconBlock, error)
+	HeadState(ctx context.Context) (iface.BeaconState, error)
 	HeadValidatorsIndices(ctx context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error)
 	HeadSeed(ctx context.Context, epoch types.Epoch) ([32]byte, error)
-	HeadGenesisValidatorsRoot() [32]byte
+	HeadGenesisValidatorRoot() [32]byte
 	HeadETH1Data() *ethpb.Eth1Data
-	HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool)
-	HeadValidatorIndexToPublicKey(ctx context.Context, index types.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error)
+	ProtoArrayStore() *protoarray.Store
 	ChainHeads() ([][32]byte, []types.Slot)
-	IsOptimistic(ctx context.Context) (bool, error)
-	IsOptimisticForRoot(ctx context.Context, root [32]byte) (bool, error)
-	HeadSyncCommitteeFetcher
-	HeadDomainFetcher
-	ForkChoicer() forkchoice.ForkChoicer
 }

 // ForkFetcher retrieves the current fork information of the Ethereum beacon chain.
 type ForkFetcher interface {
-	CurrentFork() *ethpb.Fork
+	CurrentFork() *pb.Fork
 }

 // CanonicalFetcher retrieves the current chain's canonical information.
@@ -82,45 +71,31 @@ type FinalizationFetcher interface {
 	PreviousJustifiedCheckpt() *ethpb.Checkpoint
 }

-// FinalizedCheckpt returns the latest finalized checkpoint from chain store.
+// FinalizedCheckpt returns the latest finalized checkpoint from head state.
 func (s *Service) FinalizedCheckpt() *ethpb.Checkpoint {
-	cp := s.store.FinalizedCheckpt()
-	if cp == nil {
+	if s.finalizedCheckpt == nil {
 		return &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	}

-	return ethpb.CopyCheckpoint(cp)
+	return copyutil.CopyCheckpoint(s.finalizedCheckpt)
 }

-// CurrentJustifiedCheckpt returns the current justified checkpoint from chain store.
+// CurrentJustifiedCheckpt returns the current justified checkpoint from head state.
 func (s *Service) CurrentJustifiedCheckpt() *ethpb.Checkpoint {
-	cp := s.store.JustifiedCheckpt()
-	if cp == nil {
+	if s.justifiedCheckpt == nil {
 		return &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	}

-	return ethpb.CopyCheckpoint(cp)
+	return copyutil.CopyCheckpoint(s.justifiedCheckpt)
 }

-// PreviousJustifiedCheckpt returns the previous justified checkpoint from chain store.
+// PreviousJustifiedCheckpt returns the previous justified checkpoint from head state.
 func (s *Service) PreviousJustifiedCheckpt() *ethpb.Checkpoint {
-	cp := s.store.PrevJustifiedCheckpt()
-	if cp == nil {
+	if s.prevJustifiedCheckpt == nil {
 		return &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	}

-	return ethpb.CopyCheckpoint(cp)
-}
-
-// BestJustifiedCheckpt returns the best justified checkpoint from store.
-func (s *Service) BestJustifiedCheckpt() *ethpb.Checkpoint {
-	cp := s.store.BestJustifiedCheckpt()
-	// If there is no best justified checkpoint, return the checkpoint with root as zeros to be used for genesis cases.
-	if cp == nil {
-		return &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
-	}
-
-	return ethpb.CopyCheckpoint(cp)
+	return copyutil.CopyCheckpoint(s.prevJustifiedCheckpt)
 }

 // HeadSlot returns the slot of the head of the chain.
@@ -164,7 +139,7 @@ func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
 // HeadBlock returns the head block of the chain.
 // If the head is nil from service struct,
 // it will attempt to get the head block from DB.
-func (s *Service) HeadBlock(ctx context.Context) (block.SignedBeaconBlock, error) {
+func (s *Service) HeadBlock(ctx context.Context) (interfaces.SignedBeaconBlock, error) {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()

@@ -178,7 +153,7 @@ func (s *Service) HeadBlock(ctx context.Context) (block.SignedBeaconBlock, error
 // HeadState returns the head state of the chain.
 // If the head is nil from service struct,
 // it will attempt to get the head state from DB.
-func (s *Service) HeadState(ctx context.Context) (state.BeaconState, error) {
+func (s *Service) HeadState(ctx context.Context) (iface.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.HeadState")
 	defer span.End()
 	s.headLock.RLock()
@@ -202,7 +177,7 @@ func (s *Service) HeadValidatorsIndices(ctx context.Context, epoch types.Epoch)
 	if !s.hasHeadState() {
 		return []types.ValidatorIndex{}, nil
 	}
-	return helpers.ActiveValidatorIndices(ctx, s.headState(ctx), epoch)
+	return helpers.ActiveValidatorIndices(s.headState(ctx), epoch)
 }

 // HeadSeed returns the seed from the head view of a given epoch.
@@ -217,8 +192,8 @@ func (s *Service) HeadSeed(ctx context.Context, epoch types.Epoch) ([32]byte, er
 	return helpers.Seed(s.headState(ctx), epoch, params.BeaconConfig().DomainBeaconAttester)
 }

-// HeadGenesisValidatorsRoot returns genesis validators root of the head state.
-func (s *Service) HeadGenesisValidatorsRoot() [32]byte {
+// HeadGenesisValidatorRoot returns genesis validator root of the head state.
+func (s *Service) HeadGenesisValidatorRoot() [32]byte {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()

@@ -226,7 +201,7 @@ func (s *Service) HeadGenesisValidatorsRoot() [32]byte {
 		return [32]byte{}
 	}

-	return s.headGenesisValidatorsRoot()
+	return s.headGenesisValidatorRoot()
 }

 // HeadETH1Data returns the eth1data of the current head state.
@@ -240,30 +215,35 @@ func (s *Service) HeadETH1Data() *ethpb.Eth1Data {
 	return s.head.state.Eth1Data()
 }

+// ProtoArrayStore returns the proto array store object.
+func (s *Service) ProtoArrayStore() *protoarray.Store {
+	return s.cfg.ForkChoiceStore.Store()
+}
+
 // GenesisTime returns the genesis time of beacon chain.
 func (s *Service) GenesisTime() time.Time {
 	return s.genesisTime
 }

-// GenesisValidatorsRoot returns the genesis validator
+// GenesisValidatorRoot returns the genesis validator
 // root of the chain.
-func (s *Service) GenesisValidatorsRoot() [32]byte {
+func (s *Service) GenesisValidatorRoot() [32]byte {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()

 	if !s.hasHeadState() {
 		return [32]byte{}
 	}
-	return bytesutil.ToBytes32(s.head.state.GenesisValidatorsRoot())
+	return bytesutil.ToBytes32(s.head.state.GenesisValidatorRoot())
 }

 // CurrentFork retrieves the latest fork information of the beacon chain.
-func (s *Service) CurrentFork() *ethpb.Fork {
+func (s *Service) CurrentFork() *pb.Fork {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()

 	if !s.hasHeadState() {
-		return &ethpb.Fork{
+		return &pb.Fork{
 			PreviousVersion: params.BeaconConfig().GenesisForkVersion,
 			CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
 		}
@@ -285,103 +265,21 @@ func (s *Service) IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, er
 // ChainHeads returns all possible chain heads (leaves of fork choice tree).
 // Heads roots and heads slots are returned.
 func (s *Service) ChainHeads() ([][32]byte, []types.Slot) {
-	return s.cfg.ForkChoiceStore.Tips()
-}
-
-// HeadPublicKeyToValidatorIndex returns the validator index of the `pubkey` in current head state.
-func (s *Service) HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool) {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-	if !s.hasHeadState() {
-		return 0, false
-	}
-	return s.headValidatorIndexAtPubkey(pubKey)
-}
-
-// HeadValidatorIndexToPublicKey returns the pubkey of the validator `index`  in current head state.
-func (s *Service) HeadValidatorIndexToPublicKey(_ context.Context, index types.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error) {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-	if !s.hasHeadState() {
-		return [fieldparams.BLSPubkeyLength]byte{}, nil
-	}
-	v, err := s.headValidatorAtIndex(index)
-	if err != nil {
-		return [fieldparams.BLSPubkeyLength]byte{}, err
-	}
-	return v.PublicKey(), nil
-}
-
-// ForkChoicer returns the forkchoice interface
-func (s *Service) ForkChoicer() forkchoice.ForkChoicer {
-	return s.cfg.ForkChoiceStore
-}
-
-// IsOptimistic returns true if the current head is optimistic.
-func (s *Service) IsOptimistic(ctx context.Context) (bool, error) {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-	if slots.ToEpoch(s.CurrentSlot()) < params.BeaconConfig().BellatrixForkEpoch {
-		return false, nil
-	}
-
-	return s.IsOptimisticForRoot(ctx, s.head.root)
-}
-
-// IsOptimisticForRoot takes the root and slot as arguments instead of the current head
-// and returns true if it is optimistic.
-func (s *Service) IsOptimisticForRoot(ctx context.Context, root [32]byte) (bool, error) {
-	optimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(ctx, root)
-	if err == nil {
-		return optimistic, nil
-	}
-	if err != protoarray.ErrUnknownNodeRoot && err != doublylinkedtree.ErrNilNode {
-		return false, err
-	}
-	ss, err := s.cfg.BeaconDB.StateSummary(ctx, root)
-	if err != nil {
-		return false, err
-	}
-	if ss == nil {
-		return false, errInvalidNilSummary
-	}
-
-	validatedCheckpoint, err := s.cfg.BeaconDB.LastValidatedCheckpoint(ctx)
-	if err != nil {
-		return false, err
-	}
-	if slots.ToEpoch(ss.Slot) > validatedCheckpoint.Epoch {
-		return true, nil
-	}
-
-	if slots.ToEpoch(ss.Slot)+1 < validatedCheckpoint.Epoch {
-		return false, nil
-	}
-
-	lastValidated, err := s.cfg.BeaconDB.StateSummary(ctx, bytesutil.ToBytes32(validatedCheckpoint.Root))
-	if err != nil {
-		return false, err
-	}
-
-	if ss.Slot > lastValidated.Slot {
-		return true, nil
-	}
-
-	isCanonical, err := s.IsCanonical(ctx, root)
-	if err != nil {
-		return false, err
-	}
-
-	// historical non-canonical blocks here are returned as optimistic for safety.
-	return !isCanonical, nil
-}
-
-// SetGenesisTime sets the genesis time of beacon chain.
-func (s *Service) SetGenesisTime(t time.Time) {
-	s.genesisTime = t
-}
-
-// ForkChoiceStore returns the fork choice store in the service
-func (s *Service) ForkChoiceStore() forkchoice.ForkChoicer {
-	return s.cfg.ForkChoiceStore
+	nodes := s.ProtoArrayStore().Nodes()
+
+	// Deliberate choice to not preallocate space for below.
+	// Heads cant be more than 2-3 in the worst case where pre-allocation will be 64 to begin with.
+	headsRoots := make([][32]byte, 0)
+	headsSlots := make([]types.Slot, 0)
+
+	nonExistentNode := ^uint64(0)
+	for _, node := range nodes {
+		// Possible heads have no children.
+		if node.BestDescendant() == nonExistentNode && node.BestChild() == nonExistentNode {
+			headsRoots = append(headsRoots, node.Root())
+			headsSlots = append(headsSlots, node.Slot())
+		}
+	}
+
+	return headsRoots, headsSlots
 }
--- a/beacon-chain/blockchain/chain_info_norace_test.go
+++ b/beacon-chain/blockchain/chain_info_norace_test.go
@@ -6,70 +6,56 @@ import (

 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/require"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestHeadSlot_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		cfg: &config{BeaconDB: beaconDB},
+		cfg: &Config{BeaconDB: beaconDB},
 	}
-	wait := make(chan struct{})
 	go func() {
-		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	s.HeadSlot()
-	<-wait
 }

 func TestHeadRoot_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		cfg:  &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		cfg:  &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 		head: &head{root: [32]byte{'A'}},
 	}
-	wait := make(chan struct{})
 	go func() {
-		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	_, err := s.HeadRoot(context.Background())
 	require.NoError(t, err)
-	<-wait
 }

 func TestHeadBlock_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(&ethpb.SignedBeaconBlock{})
-	require.NoError(t, err)
 	s := &Service{
-		cfg:  &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
-		head: &head{block: wsb},
+		cfg:  &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		head: &head{block: interfaces.WrappedPhase0SignedBeaconBlock(&ethpb.SignedBeaconBlock{})},
 	}
-	wait := make(chan struct{})
 	go func() {
-		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
-	_, err = s.HeadBlock(context.Background())
+	_, err := s.HeadBlock(context.Background())
 	require.NoError(t, err)
-	<-wait
 }

 func TestHeadState_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		cfg: &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 	}
-	wait := make(chan struct{})
 	go func() {
-		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	_, err := s.HeadState(context.Background())
 	require.NoError(t, err)
-	<-wait
 }
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -8,17 +8,16 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	"google.golang.org/protobuf/proto"
 )

@@ -41,18 +40,12 @@ func TestHeadRoot_Nil(t *testing.T) {
 	assert.DeepEqual(t, params.BeaconConfig().ZeroHash[:], headRoot, "Incorrect pre chain start value")
 }

-func TestService_ForkChoiceStore(t *testing.T) {
-	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}}
-	p := c.ForkChoiceStore()
-	require.Equal(t, 0, int(p.FinalizedEpoch()))
-}
-
 func TestFinalizedCheckpt_CanRetrieve(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)

 	cp := &ethpb.Checkpoint{Epoch: 5, Root: bytesutil.PadTo([]byte("foo"), 32)}
 	c := setupBeaconChain(t, beaconDB)
-	c.store.SetFinalizedCheckpt(cp)
+	c.finalizedCheckpt = cp

 	assert.Equal(t, cp.Epoch, c.FinalizedCheckpt().Epoch, "Unexpected finalized epoch")
 }
@@ -63,9 +56,9 @@ func TestFinalizedCheckpt_GenesisRootOk(t *testing.T) {
 	genesisRoot := [32]byte{'A'}
 	cp := &ethpb.Checkpoint{Root: genesisRoot[:]}
 	c := setupBeaconChain(t, beaconDB)
-	c.store.SetFinalizedCheckpt(cp)
-	c.originBlockRoot = genesisRoot
-	assert.DeepEqual(t, c.originBlockRoot[:], c.FinalizedCheckpt().Root)
+	c.finalizedCheckpt = cp
+	c.genesisRoot = genesisRoot
+	assert.DeepEqual(t, c.genesisRoot[:], c.FinalizedCheckpt().Root)
 }

 func TestCurrentJustifiedCheckpt_CanRetrieve(t *testing.T) {
@@ -74,7 +67,7 @@ func TestCurrentJustifiedCheckpt_CanRetrieve(t *testing.T) {
 	c := setupBeaconChain(t, beaconDB)
 	assert.Equal(t, params.BeaconConfig().ZeroHash, bytesutil.ToBytes32(c.CurrentJustifiedCheckpt().Root), "Unexpected justified epoch")
 	cp := &ethpb.Checkpoint{Epoch: 6, Root: bytesutil.PadTo([]byte("foo"), 32)}
-	c.store.SetJustifiedCheckpt(cp)
+	c.justifiedCheckpt = cp
 	assert.Equal(t, cp.Epoch, c.CurrentJustifiedCheckpt().Epoch, "Unexpected justified epoch")
 }

@@ -84,9 +77,9 @@ func TestJustifiedCheckpt_GenesisRootOk(t *testing.T) {
 	c := setupBeaconChain(t, beaconDB)
 	genesisRoot := [32]byte{'B'}
 	cp := &ethpb.Checkpoint{Root: genesisRoot[:]}
-	c.store.SetJustifiedCheckpt(cp)
-	c.originBlockRoot = genesisRoot
-	assert.DeepEqual(t, c.originBlockRoot[:], c.CurrentJustifiedCheckpt().Root)
+	c.justifiedCheckpt = cp
+	c.genesisRoot = genesisRoot
+	assert.DeepEqual(t, c.genesisRoot[:], c.CurrentJustifiedCheckpt().Root)
 }

 func TestPreviousJustifiedCheckpt_CanRetrieve(t *testing.T) {
@@ -95,7 +88,7 @@ func TestPreviousJustifiedCheckpt_CanRetrieve(t *testing.T) {
 	cp := &ethpb.Checkpoint{Epoch: 7, Root: bytesutil.PadTo([]byte("foo"), 32)}
 	c := setupBeaconChain(t, beaconDB)
 	assert.Equal(t, params.BeaconConfig().ZeroHash, bytesutil.ToBytes32(c.CurrentJustifiedCheckpt().Root), "Unexpected justified epoch")
-	c.store.SetPrevJustifiedCheckpt(cp)
+	c.prevJustifiedCheckpt = cp
 	assert.Equal(t, cp.Epoch, c.PreviousJustifiedCheckpt().Epoch, "Unexpected previous justified epoch")
 }

@@ -105,14 +98,14 @@ func TestPrevJustifiedCheckpt_GenesisRootOk(t *testing.T) {
 	genesisRoot := [32]byte{'C'}
 	cp := &ethpb.Checkpoint{Root: genesisRoot[:]}
 	c := setupBeaconChain(t, beaconDB)
-	c.store.SetPrevJustifiedCheckpt(cp)
-	c.originBlockRoot = genesisRoot
-	assert.DeepEqual(t, c.originBlockRoot[:], c.PreviousJustifiedCheckpt().Root)
+	c.prevJustifiedCheckpt = cp
+	c.genesisRoot = genesisRoot
+	assert.DeepEqual(t, c.genesisRoot[:], c.PreviousJustifiedCheckpt().Root)
 }

 func TestHeadSlot_CanRetrieve(t *testing.T) {
 	c := &Service{}
-	s, err := v1.InitializeFromProto(&ethpb.BeaconState{})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{})
 	require.NoError(t, err)
 	c.head = &head{slot: 100, state: s}
 	assert.Equal(t, types.Slot(100), c.HeadSlot())
@@ -128,15 +121,13 @@ func TestHeadRoot_CanRetrieve(t *testing.T) {

 func TestHeadRoot_UseDB(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
-	c := &Service{cfg: &config{BeaconDB: beaconDB}}
+	c := &Service{cfg: &Config{BeaconDB: beaconDB}}
 	c.head = &head{root: params.BeaconConfig().ZeroHash}
-	b := util.NewBeaconBlock()
+	b := testutil.NewBeaconBlock()
 	br, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: br[:]}))
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), interfaces.WrappedPhase0SignedBeaconBlock(b)))
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Root: br[:]}))
 	require.NoError(t, beaconDB.SaveHeadBlockRoot(context.Background(), br))
 	r, err := c.HeadRoot(context.Background())
 	require.NoError(t, err)
@@ -144,14 +135,12 @@ func TestHeadRoot_UseDB(t *testing.T) {
 }

 func TestHeadBlock_CanRetrieve(t *testing.T) {
-	b := util.NewBeaconBlock()
+	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 1
-	s, err := v1.InitializeFromProto(&ethpb.BeaconState{})
-	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{})
 	require.NoError(t, err)
 	c := &Service{}
-	c.head = &head{block: wsb, state: s}
+	c.head = &head{block: interfaces.WrappedPhase0SignedBeaconBlock(b), state: s}

 	recevied, err := c.HeadBlock(context.Background())
 	require.NoError(t, err)
@@ -159,7 +148,7 @@ func TestHeadBlock_CanRetrieve(t *testing.T) {
 }

 func TestHeadState_CanRetrieve(t *testing.T) {
-	s, err := v1.InitializeFromProto(&ethpb.BeaconState{Slot: 2, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Slot: 2, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
 	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
@@ -175,8 +164,8 @@ func TestGenesisTime_CanRetrieve(t *testing.T) {
 }

 func TestCurrentFork_CanRetrieve(t *testing.T) {
-	f := &ethpb.Fork{Epoch: 999}
-	s, err := v1.InitializeFromProto(&ethpb.BeaconState{Fork: f})
+	f := &pb.Fork{Epoch: 999}
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Fork: f})
 	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
@@ -186,7 +175,7 @@ func TestCurrentFork_CanRetrieve(t *testing.T) {
 }

 func TestCurrentFork_NilHeadSTate(t *testing.T) {
-	f := &ethpb.Fork{
+	f := &pb.Fork{
 		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
 		CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
 	}
@@ -196,15 +185,15 @@ func TestCurrentFork_NilHeadSTate(t *testing.T) {
 	}
 }

-func TestGenesisValidatorsRoot_CanRetrieve(t *testing.T) {
+func TestGenesisValidatorRoot_CanRetrieve(t *testing.T) {
 	// Should not panic if head state is nil.
 	c := &Service{}
-	assert.Equal(t, [32]byte{}, c.GenesisValidatorsRoot(), "Did not get correct genesis validators root")
+	assert.Equal(t, [32]byte{}, c.GenesisValidatorRoot(), "Did not get correct genesis validator root")

-	s, err := v1.InitializeFromProto(&ethpb.BeaconState{GenesisValidatorsRoot: []byte{'a'}})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{GenesisValidatorsRoot: []byte{'a'}})
 	require.NoError(t, err)
 	c.head = &head{state: s}
-	assert.Equal(t, [32]byte{'a'}, c.GenesisValidatorsRoot(), "Did not get correct genesis validators root")
+	assert.Equal(t, [32]byte{'a'}, c.GenesisValidatorRoot(), "Did not get correct genesis validator root")
 }

 func TestHeadETH1Data_Nil(t *testing.T) {
@@ -215,7 +204,7 @@ func TestHeadETH1Data_Nil(t *testing.T) {

 func TestHeadETH1Data_CanRetrieve(t *testing.T) {
 	d := &ethpb.Eth1Data{DepositCount: 999}
-	s, err := v1.InitializeFromProto(&ethpb.BeaconState{Eth1Data: d})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Eth1Data: d})
 	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
@@ -229,13 +218,11 @@ func TestIsCanonical_Ok(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	c := setupBeaconChain(t, beaconDB)

-	blk := util.NewBeaconBlock()
+	blk := testutil.NewBeaconBlock()
 	blk.Block.Slot = 0
 	root, err := blk.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(blk)))
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, root))
 	can, err := c.IsCanonical(ctx, root)
 	require.NoError(t, err)
@@ -247,7 +234,7 @@ func TestIsCanonical_Ok(t *testing.T) {
 }

 func TestService_HeadValidatorsIndices(t *testing.T) {
-	s, _ := util.DeterministicGenesisState(t, 10)
+	s, _ := testutil.DeterministicGenesisState(t, 10)
 	c := &Service{}

 	c.head = &head{}
@@ -262,7 +249,7 @@ func TestService_HeadValidatorsIndices(t *testing.T) {
 }

 func TestService_HeadSeed(t *testing.T) {
-	s, _ := util.DeterministicGenesisState(t, 1)
+	s, _ := testutil.DeterministicGenesisState(t, 1)
 	c := &Service{}
 	seed, err := helpers.Seed(s, 0, params.BeaconConfig().DomainBeaconAttester)
 	require.NoError(t, err)
@@ -278,314 +265,35 @@ func TestService_HeadSeed(t *testing.T) {
 	require.DeepEqual(t, seed, root)
 }

-func TestService_HeadGenesisValidatorsRoot(t *testing.T) {
-	s, _ := util.DeterministicGenesisState(t, 1)
+func TestService_HeadGenesisValidatorRoot(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisState(t, 1)
 	c := &Service{}

 	c.head = &head{}
-	root := c.HeadGenesisValidatorsRoot()
+	root := c.HeadGenesisValidatorRoot()
 	require.Equal(t, [32]byte{}, root)

 	c.head = &head{state: s}
-	root = c.HeadGenesisValidatorsRoot()
-	require.DeepEqual(t, root[:], s.GenesisValidatorsRoot())
+	root = c.HeadGenesisValidatorRoot()
+	require.DeepEqual(t, root[:], s.GenesisValidatorRoot())
 }
-func TestService_ChainHeads_ProtoArray(t *testing.T) {
+
+func TestService_ProtoArrayStore(t *testing.T) {
+	c := &Service{cfg: &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}}
+	p := c.ProtoArrayStore()
+	require.Equal(t, 0, int(p.FinalizedEpoch()))
+}
+
+func TestService_ChainHeads(t *testing.T) {
 	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0,
-		params.BeaconConfig().ZeroHash)}}
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, params.BeaconConfig().ZeroHash, 0, 0))
+	c := &Service{cfg: &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}}
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 103, [32]byte{'d'}, [32]byte{}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, [32]byte{}, 0, 0))

 	roots, slots := c.ChainHeads()
 	require.DeepEqual(t, [][32]byte{{'c'}, {'d'}, {'e'}}, roots)
 	require.DeepEqual(t, []types.Slot{102, 103, 104}, slots)
 }
-
-func TestService_ChainHeads_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}}
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, params.BeaconConfig().ZeroHash, 0, 0))
-
-	roots, slots := c.ChainHeads()
-	require.Equal(t, 3, len(roots))
-	rootMap := map[[32]byte]types.Slot{[32]byte{'c'}: 102, [32]byte{'d'}: 103, [32]byte{'e'}: 104}
-	for i, root := range roots {
-		slot, ok := rootMap[root]
-		require.Equal(t, true, ok)
-		require.Equal(t, slot, slots[i])
-	}
-}
-
-func TestService_HeadPublicKeyToValidatorIndex(t *testing.T) {
-	s, _ := util.DeterministicGenesisState(t, 10)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	_, e := c.HeadPublicKeyToValidatorIndex([fieldparams.BLSPubkeyLength]byte{})
-	require.Equal(t, false, e)
-
-	v, err := s.ValidatorAtIndex(0)
-	require.NoError(t, err)
-
-	i, e := c.HeadPublicKeyToValidatorIndex(bytesutil.ToBytes48(v.PublicKey))
-	require.Equal(t, true, e)
-	require.Equal(t, types.ValidatorIndex(0), i)
-}
-
-func TestService_HeadPublicKeyToValidatorIndexNil(t *testing.T) {
-	c := &Service{}
-	c.head = nil
-
-	idx, e := c.HeadPublicKeyToValidatorIndex([fieldparams.BLSPubkeyLength]byte{})
-	require.Equal(t, false, e)
-	require.Equal(t, types.ValidatorIndex(0), idx)
-
-	c.head = &head{state: nil}
-	i, e := c.HeadPublicKeyToValidatorIndex([fieldparams.BLSPubkeyLength]byte{})
-	require.Equal(t, false, e)
-	require.Equal(t, types.ValidatorIndex(0), i)
-}
-
-func TestService_HeadValidatorIndexToPublicKey(t *testing.T) {
-	s, _ := util.DeterministicGenesisState(t, 10)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	p, err := c.HeadValidatorIndexToPublicKey(context.Background(), 0)
-	require.NoError(t, err)
-
-	v, err := s.ValidatorAtIndex(0)
-	require.NoError(t, err)
-
-	require.Equal(t, bytesutil.ToBytes48(v.PublicKey), p)
-}
-
-func TestService_HeadValidatorIndexToPublicKeyNil(t *testing.T) {
-	c := &Service{}
-	c.head = nil
-
-	p, err := c.HeadValidatorIndexToPublicKey(context.Background(), 0)
-	require.NoError(t, err)
-	require.Equal(t, [fieldparams.BLSPubkeyLength]byte{}, p)
-
-	c.head = &head{state: nil}
-	p, err = c.HeadValidatorIndexToPublicKey(context.Background(), 0)
-	require.NoError(t, err)
-	require.Equal(t, [fieldparams.BLSPubkeyLength]byte{}, p)
-}
-
-func TestService_IsOptimistic_ProtoArray(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-	cfg := params.BeaconConfig()
-	cfg.BellatrixForkEpoch = 0
-	params.OverrideBeaconConfig(cfg)
-
-	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 0, 0))
-
-	opt, err := c.IsOptimistic(ctx)
-	require.NoError(t, err)
-	require.Equal(t, true, opt)
-}
-
-func TestService_IsOptimistic_DoublyLinkedTree(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-	cfg := params.BeaconConfig()
-	cfg.BellatrixForkEpoch = 0
-	params.OverrideBeaconConfig(cfg)
-
-	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 0, 0))
-
-	opt, err := c.IsOptimistic(ctx)
-	require.NoError(t, err)
-	require.Equal(t, true, opt)
-}
-
-func TestService_IsOptimisticBeforeBellatrix(t *testing.T) {
-	ctx := context.Background()
-	c := &Service{genesisTime: time.Now()}
-	opt, err := c.IsOptimistic(ctx)
-	require.NoError(t, err)
-	require.Equal(t, false, opt)
-}
-
-func TestService_IsOptimisticForRoot_ProtoArray(t *testing.T) {
-	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 0, 0))
-
-	opt, err := c.IsOptimisticForRoot(ctx, [32]byte{'a'})
-	require.NoError(t, err)
-	require.Equal(t, true, opt)
-}
-
-func TestService_IsOptimisticForRoot_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 0, 0))
-
-	opt, err := c.IsOptimisticForRoot(ctx, [32]byte{'a'})
-	require.NoError(t, err)
-	require.Equal(t, true, opt)
-}
-
-func TestService_IsOptimisticForRoot_DB_ProtoArray(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	ctx := context.Background()
-	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	c.head = &head{root: params.BeaconConfig().ZeroHash}
-	b := util.NewBeaconBlock()
-	b.Block.Slot = 10
-	br, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: br[:], Slot: 10}))
-
-	optimisticBlock := util.NewBeaconBlock()
-	optimisticBlock.Block.Slot = 97
-	optimisticRoot, err := optimisticBlock.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(optimisticBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-
-	validatedBlock := util.NewBeaconBlock()
-	validatedBlock.Block.Slot = 9
-	validatedRoot, err := validatedBlock.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(validatedBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-
-	validatedCheckpoint := &ethpb.Checkpoint{Root: br[:]}
-	require.NoError(t, beaconDB.SaveLastValidatedCheckpoint(ctx, validatedCheckpoint))
-
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: optimisticRoot[:], Slot: 11}))
-	optimistic, err := c.IsOptimisticForRoot(ctx, optimisticRoot)
-	require.NoError(t, err)
-	require.Equal(t, true, optimistic)
-
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: validatedRoot[:], Slot: 9}))
-	cp := &ethpb.Checkpoint{
-		Epoch: 1,
-		Root:  validatedRoot[:],
-	}
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, validatedRoot))
-	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, cp))
-
-	validated, err := c.IsOptimisticForRoot(ctx, validatedRoot)
-	require.NoError(t, err)
-	require.Equal(t, false, validated)
-}
-
-func TestService_IsOptimisticForRoot_DB_DoublyLinkedTree(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	ctx := context.Background()
-	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: doublylinkedtree.New(0, 0)}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	c.head = &head{root: params.BeaconConfig().ZeroHash}
-	b := util.NewBeaconBlock()
-	b.Block.Slot = 10
-	br, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: br[:], Slot: 10}))
-
-	optimisticBlock := util.NewBeaconBlock()
-	optimisticBlock.Block.Slot = 97
-	optimisticRoot, err := optimisticBlock.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(optimisticBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-
-	validatedBlock := util.NewBeaconBlock()
-	validatedBlock.Block.Slot = 9
-	validatedRoot, err := validatedBlock.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(validatedBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-
-	validatedCheckpoint := &ethpb.Checkpoint{Root: br[:]}
-	require.NoError(t, beaconDB.SaveLastValidatedCheckpoint(ctx, validatedCheckpoint))
-
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: optimisticRoot[:], Slot: 11}))
-	optimistic, err := c.IsOptimisticForRoot(ctx, optimisticRoot)
-	require.NoError(t, err)
-	require.Equal(t, true, optimistic)
-
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: validatedRoot[:], Slot: 9}))
-	cp := &ethpb.Checkpoint{
-		Epoch: 1,
-		Root:  validatedRoot[:],
-	}
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, validatedRoot))
-	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, cp))
-	validated, err := c.IsOptimisticForRoot(ctx, validatedRoot)
-	require.NoError(t, err)
-	require.Equal(t, false, validated)
-}
-
-func TestService_IsOptimisticForRoot_DB_non_canonical(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	ctx := context.Background()
-	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: doublylinkedtree.New(0, 0)}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	c.head = &head{root: params.BeaconConfig().ZeroHash}
-	b := util.NewBeaconBlock()
-	b.Block.Slot = 10
-	br, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: br[:], Slot: 10}))
-
-	optimisticBlock := util.NewBeaconBlock()
-	optimisticBlock.Block.Slot = 97
-	optimisticRoot, err := optimisticBlock.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(optimisticBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-
-	validatedBlock := util.NewBeaconBlock()
-	validatedBlock.Block.Slot = 9
-	validatedRoot, err := validatedBlock.Block.HashTreeRoot()
-	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(validatedBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
-
-	validatedCheckpoint := &ethpb.Checkpoint{Root: br[:]}
-	require.NoError(t, beaconDB.SaveLastValidatedCheckpoint(ctx, validatedCheckpoint))
-
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: optimisticRoot[:], Slot: 11}))
-	optimistic, err := c.IsOptimisticForRoot(ctx, optimisticRoot)
-	require.NoError(t, err)
-	require.Equal(t, true, optimistic)
-
-	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: validatedRoot[:], Slot: 9}))
-	validated, err := c.IsOptimisticForRoot(ctx, validatedRoot)
-	require.NoError(t, err)
-	require.Equal(t, true, validated)
-
-}
--- a/beacon-chain/blockchain/checktags_test.go
+++ b/beacon-chain/blockchain/checktags_test.go
@@ -1,4 +1,3 @@
-//go:build !develop
 // +build !develop

 package blockchain
--- a/beacon-chain/blockchain/error.go
+++ b/beacon-chain/blockchain/error.go
@@ -1,21 +0,0 @@
-package blockchain
-
-import "github.com/pkg/errors"
-
-var (
-	// errNilJustifiedInStore is returned when a nil justified checkpt is returned from store.
-	errNilJustifiedInStore = errors.New("nil justified checkpoint returned from store")
-	// errNilBestJustifiedInStore is returned when a nil justified checkpt is returned from store.
-	errNilBestJustifiedInStore = errors.New("nil best justified checkpoint returned from store")
-	// errNilFinalizedInStore is returned when a nil finalized checkpt is returned from store.
-	errNilFinalizedInStore = errors.New("nil finalized checkpoint returned from store")
-	// errInvalidNilSummary is returned when a nil summary is returned from the DB.
-	errInvalidNilSummary = errors.New("nil summary returned from the DB")
-	// errNilParentInDB is returned when a nil parent block is returned from the DB.
-	errNilParentInDB = errors.New("nil parent block in DB")
-	// errWrongBlockCount is returned when the wrong number of blocks or
-	// block roots is used
-	errWrongBlockCount = errors.New("wrong number of blocks or block roots")
-	// block is not a valid optimistic candidate block
-	errNotOptimisticCandidate = errors.New("block is not suitable for optimistic sync")
-)
--- a/beacon-chain/blockchain/head.go
+++ b/beacon-chain/blockchain/head.go
@@ -10,67 +10,49 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/config/features"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	ethpbv1 "github.com/prysmaticlabs/prysm/proto/eth/v1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/slotutil"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

-// UpdateAndSaveHeadWithBalances updates the beacon state head after getting justified balanced from cache.
-// This function is only used in spec-tests, it does save the head after updating it.
-func (s *Service) UpdateAndSaveHeadWithBalances(ctx context.Context) error {
-	cp := s.store.JustifiedCheckpt()
-	if cp == nil {
-		return errors.New("no justified checkpoint")
-	}
-	balances, err := s.justifiedBalances.get(ctx, bytesutil.ToBytes32(cp.Root))
-	if err != nil {
-		msg := fmt.Sprintf("could not read balances for state w/ justified checkpoint %#x", cp.Root)
-		return errors.Wrap(err, msg)
-	}
-	headRoot, err := s.updateHead(ctx, balances)
-	if err != nil {
-		return errors.Wrap(err, "could not update head")
-	}
-	return s.saveHead(ctx, headRoot)
-}
-
 // This defines the current chain service's view of head.
 type head struct {
-	slot  types.Slot              // current head slot.
-	root  [32]byte                // current head root.
-	block block.SignedBeaconBlock // current head block.
-	state state.BeaconState       // current head state.
+	slot  types.Slot                   // current head slot.
+	root  [32]byte                     // current head root.
+	block interfaces.SignedBeaconBlock // current head block.
+	state iface.BeaconState            // current head state.
 }

 // Determined the head from the fork choice service and saves its new data
 // (head root, head block, and head state) to the local service cache.
-func (s *Service) updateHead(ctx context.Context, balances []uint64) ([32]byte, error) {
+func (s *Service) updateHead(ctx context.Context, balances []uint64) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.updateHead")
 	defer span.End()

+	// To get the proper head update, a node first checks its best justified
+	// can become justified. This is designed to prevent bounce attack and
+	// ensure head gets its best justified info.
+	if s.bestJustifiedCheckpt.Epoch > s.justifiedCheckpt.Epoch {
+		s.justifiedCheckpt = s.bestJustifiedCheckpt
+		if err := s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root)); err != nil {
+			return err
+		}
+	}
+
 	// Get head from the fork choice service.
-	f := s.store.FinalizedCheckpt()
-	if f == nil {
-		return [32]byte{}, errNilFinalizedInStore
-	}
-	j := s.store.JustifiedCheckpt()
-	if j == nil {
-		return [32]byte{}, errNilJustifiedInStore
-	}
-	// To get head before the first justified epoch, the fork choice will start with origin root
+	f := s.finalizedCheckpt
+	j := s.justifiedCheckpt
+	// To get head before the first justified epoch, the fork choice will start with genesis root
 	// instead of zero hashes.
 	headStartRoot := bytesutil.ToBytes32(j.Root)
 	if headStartRoot == params.BeaconConfig().ZeroHash {
-		headStartRoot = s.originBlockRoot
+		headStartRoot = s.genesisRoot
 	}

 	// In order to process head, fork choice store requires justified info.
@@ -80,19 +62,21 @@ func (s *Service) updateHead(ctx context.Context, balances []uint64) ([32]byte,
 	if !s.cfg.ForkChoiceStore.HasNode(headStartRoot) {
 		jb, err := s.cfg.BeaconDB.Block(ctx, headStartRoot)
 		if err != nil {
-			return [32]byte{}, err
-		}
-		if features.Get().EnableForkChoiceDoublyLinkedTree {
-			s.cfg.ForkChoiceStore = doublylinkedtree.New(j.Epoch, f.Epoch)
-		} else {
-			s.cfg.ForkChoiceStore = protoarray.New(j.Epoch, f.Epoch, bytesutil.ToBytes32(f.Root))
+			return err
 		}
+		s.cfg.ForkChoiceStore = protoarray.New(j.Epoch, f.Epoch, bytesutil.ToBytes32(f.Root))
 		if err := s.insertBlockToForkChoiceStore(ctx, jb.Block(), headStartRoot, f, j); err != nil {
-			return [32]byte{}, err
+			return err
 		}
 	}

-	return s.cfg.ForkChoiceStore.Head(ctx, j.Epoch, headStartRoot, balances, f.Epoch)
+	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx, j.Epoch, headStartRoot, balances, f.Epoch)
+	if err != nil {
+		return err
+	}
+
+	// Save head to the local service cache.
+	return s.saveHead(ctx, headRoot)
 }

 // This saves head info to the local service cache, it also saves the
@@ -121,8 +105,8 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 	if err != nil {
 		return err
 	}
-	if err := helpers.BeaconBlockIsNil(newHeadBlock); err != nil {
-		return err
+	if newHeadBlock == nil || newHeadBlock.IsNil() || newHeadBlock.Block().IsNil() {
+		return errors.New("cannot save nil head block")
 	}

 	// Get the new head state from cached state or DB.
@@ -145,29 +129,20 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 			"newSlot": fmt.Sprintf("%d", newHeadSlot),
 			"oldSlot": fmt.Sprintf("%d", headSlot),
 		}).Debug("Chain reorg occurred")
-		absoluteSlotDifference := slots.AbsoluteValueSlotDifference(newHeadSlot, headSlot)
-		isOptimistic, err := s.IsOptimistic(ctx)
-		if err != nil {
-			return errors.Wrap(err, "could not check if node is optimistically synced")
-		}
+		absoluteSlotDifference := slotutil.AbsoluteValueSlotDifference(newHeadSlot, headSlot)
 		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.Reorg,
 			Data: &ethpbv1.EventChainReorg{
-				Slot:                newHeadSlot,
-				Depth:               absoluteSlotDifference,
-				OldHeadBlock:        oldHeadRoot[:],
-				NewHeadBlock:        headRoot[:],
-				OldHeadState:        oldStateRoot,
-				NewHeadState:        newStateRoot,
-				Epoch:               slots.ToEpoch(newHeadSlot),
-				ExecutionOptimistic: isOptimistic,
+				Slot:         newHeadSlot,
+				Depth:        absoluteSlotDifference,
+				OldHeadBlock: oldHeadRoot[:],
+				NewHeadBlock: headRoot[:],
+				OldHeadState: oldStateRoot,
+				NewHeadState: newStateRoot,
+				Epoch:        helpers.SlotToEpoch(newHeadSlot),
 			},
 		})

-		if err := s.saveOrphanedAtts(ctx, bytesutil.ToBytes32(r)); err != nil {
-			return err
-		}
-
 		reorgCount.Inc()
 	}

@@ -182,7 +157,7 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 	// Forward an event capturing a new chain head over a common event feed
 	// done in a goroutine to avoid blocking the critical runtime main routine.
 	go func() {
-		if err := s.notifyNewHeadEvent(ctx, newHeadSlot, newHeadState, newStateRoot, headRoot[:]); err != nil {
+		if err := s.notifyNewHeadEvent(newHeadSlot, newHeadState, newStateRoot, headRoot[:]); err != nil {
 			log.WithError(err).Error("Could not notify event feed of new chain head")
 		}
 	}()
@@ -193,8 +168,8 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 // This gets called to update canonical root mapping. It does not save head block
 // root in DB. With the inception of initial-sync-cache-state flag, it uses finalized
 // check point as anchors to resume sync therefore head is no longer needed to be saved on per slot basis.
-func (s *Service) saveHeadNoDB(ctx context.Context, b block.SignedBeaconBlock, r [32]byte, hs state.BeaconState) error {
-	if err := helpers.BeaconBlockIsNil(b); err != nil {
+func (s *Service) saveHeadNoDB(ctx context.Context, b interfaces.SignedBeaconBlock, r [32]byte, hs iface.BeaconState) error {
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
 		return err
 	}
 	cachedHeadRoot, err := s.HeadRoot(ctx)
@@ -210,7 +185,7 @@ func (s *Service) saveHeadNoDB(ctx context.Context, b block.SignedBeaconBlock, r
 }

 // This sets head view object which is used to track the head slot, root, block and state.
-func (s *Service) setHead(root [32]byte, block block.SignedBeaconBlock, state state.BeaconState) {
+func (s *Service) setHead(root [32]byte, block interfaces.SignedBeaconBlock, state iface.BeaconState) {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -226,7 +201,7 @@ func (s *Service) setHead(root [32]byte, block block.SignedBeaconBlock, state st
 // This sets head view object which is used to track the head slot, root, block and state. The method
 // assumes that state being passed into the method will not be modified by any other alternate
 // caller which holds the state's reference.
-func (s *Service) setHeadInitialSync(root [32]byte, block block.SignedBeaconBlock, state state.BeaconState) {
+func (s *Service) setHeadInitialSync(root [32]byte, block interfaces.SignedBeaconBlock, state iface.BeaconState) {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -259,38 +234,24 @@ func (s *Service) headRoot() [32]byte {
 // This returns the head block.
 // It does a full copy on head block for immutability.
 // This is a lock free version.
-func (s *Service) headBlock() block.SignedBeaconBlock {
+func (s *Service) headBlock() interfaces.SignedBeaconBlock {
 	return s.head.block.Copy()
 }

 // This returns the head state.
 // It does a full copy on head state for immutability.
 // This is a lock free version.
-func (s *Service) headState(ctx context.Context) state.BeaconState {
-	_, span := trace.StartSpan(ctx, "blockChain.headState")
+func (s *Service) headState(ctx context.Context) iface.BeaconState {
+	ctx, span := trace.StartSpan(ctx, "blockChain.headState")
 	defer span.End()

 	return s.head.state.Copy()
 }

-// This returns the genesis validators root of the head state.
+// This returns the genesis validator root of the head state.
 // This is a lock free version.
-func (s *Service) headGenesisValidatorsRoot() [32]byte {
-	return bytesutil.ToBytes32(s.head.state.GenesisValidatorsRoot())
-}
-
-// This returns the validator referenced by the provided index in
-// the head state.
-// This is a lock free version.
-func (s *Service) headValidatorAtIndex(index types.ValidatorIndex) (state.ReadOnlyValidator, error) {
-	return s.head.state.ValidatorAtIndexReadOnly(index)
-}
-
-// This returns the validator index referenced by the provided pubkey in
-// the head state.
-// This is a lock free version.
-func (s *Service) headValidatorIndexAtPubkey(pubKey [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool) {
-	return s.head.state.ValidatorIndexByPubkey(pubKey)
+func (s *Service) headGenesisValidatorRoot() [32]byte {
+	return bytesutil.ToBytes32(s.head.state.GenesisValidatorRoot())
 }

 // Returns true if head state exists.
@@ -299,28 +260,78 @@ func (s *Service) hasHeadState() bool {
 	return s.head != nil && s.head.state != nil
 }

+// This caches justified state balances to be used for fork choice.
+func (s *Service) cacheJustifiedStateBalances(ctx context.Context, justifiedRoot [32]byte) error {
+	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+		return err
+	}
+
+	s.clearInitSyncBlocks()
+
+	var justifiedState iface.BeaconState
+	var err error
+	if justifiedRoot == s.genesisRoot {
+		justifiedState, err = s.cfg.BeaconDB.GenesisState(ctx)
+		if err != nil {
+			return err
+		}
+	} else {
+		justifiedState, err = s.cfg.StateGen.StateByRoot(ctx, justifiedRoot)
+		if err != nil {
+			return err
+		}
+	}
+	if justifiedState == nil || justifiedState.IsNil() {
+		return errors.New("justified state can't be nil")
+	}
+
+	epoch := helpers.CurrentEpoch(justifiedState)
+
+	justifiedBalances := make([]uint64, justifiedState.NumValidators())
+	if err := justifiedState.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
+		if helpers.IsActiveValidatorUsingTrie(val, epoch) {
+			justifiedBalances[idx] = val.EffectiveBalance()
+		} else {
+			justifiedBalances[idx] = 0
+		}
+		return nil
+	}); err != nil {
+		return err
+	}
+
+	s.justifiedBalancesLock.Lock()
+	defer s.justifiedBalancesLock.Unlock()
+	s.justifiedBalances = justifiedBalances
+	return nil
+}
+
+func (s *Service) getJustifiedBalances() []uint64 {
+	s.justifiedBalancesLock.RLock()
+	defer s.justifiedBalancesLock.RUnlock()
+	return s.justifiedBalances
+}
+
 // Notifies a common event feed of a new chain head event. Called right after a new
 // chain head is determined, set, and saved to disk.
 func (s *Service) notifyNewHeadEvent(
-	ctx context.Context,
 	newHeadSlot types.Slot,
-	newHeadState state.BeaconState,
+	newHeadState iface.BeaconState,
 	newHeadStateRoot,
 	newHeadRoot []byte,
 ) error {
-	previousDutyDependentRoot := s.originBlockRoot[:]
-	currentDutyDependentRoot := s.originBlockRoot[:]
+	previousDutyDependentRoot := s.genesisRoot[:]
+	currentDutyDependentRoot := s.genesisRoot[:]

 	var previousDutyEpoch types.Epoch
-	currentDutyEpoch := slots.ToEpoch(newHeadSlot)
+	currentDutyEpoch := helpers.SlotToEpoch(newHeadSlot)
 	if currentDutyEpoch > 0 {
 		previousDutyEpoch = currentDutyEpoch.Sub(1)
 	}
-	currentDutySlot, err := slots.EpochStart(currentDutyEpoch)
+	currentDutySlot, err := helpers.StartSlot(currentDutyEpoch)
 	if err != nil {
 		return errors.Wrap(err, "could not get duty slot")
 	}
-	previousDutySlot, err := slots.EpochStart(previousDutyEpoch)
+	previousDutySlot, err := helpers.StartSlot(previousDutyEpoch)
 	if err != nil {
 		return errors.Wrap(err, "could not get duty slot")
 	}
@@ -336,58 +347,16 @@ func (s *Service) notifyNewHeadEvent(
 			return errors.Wrap(err, "could not get duty dependent root")
 		}
 	}
-	isOptimistic, err := s.IsOptimistic(ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not check if node is optimistically synced")
-	}
 	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 		Type: statefeed.NewHead,
 		Data: &ethpbv1.EventHead{
 			Slot:                      newHeadSlot,
 			Block:                     newHeadRoot,
 			State:                     newHeadStateRoot,
-			EpochTransition:           slots.IsEpochStart(newHeadSlot),
+			EpochTransition:           helpers.IsEpochEnd(newHeadSlot),
 			PreviousDutyDependentRoot: previousDutyDependentRoot,
 			CurrentDutyDependentRoot:  currentDutyDependentRoot,
-			ExecutionOptimistic:       isOptimistic,
 		},
 	})
 	return nil
 }
-
-// This saves the attestations inside the beacon block with respect to root `orphanedRoot` back into the
-// attestation pool. It also filters out the attestations that is one epoch older as a
-// defense so invalid attestations don't flow into the attestation pool.
-func (s *Service) saveOrphanedAtts(ctx context.Context, orphanedRoot [32]byte) error {
-	if !features.Get().CorrectlyInsertOrphanedAtts {
-		return nil
-	}
-
-	orphanedBlk, err := s.cfg.BeaconDB.Block(ctx, orphanedRoot)
-	if err != nil {
-		return err
-	}
-
-	if orphanedBlk == nil || orphanedBlk.IsNil() {
-		return errors.New("orphaned block can't be nil")
-	}
-
-	for _, a := range orphanedBlk.Block().Body().Attestations() {
-		// Is the attestation one epoch older.
-		if a.Data.Slot+params.BeaconConfig().SlotsPerEpoch < s.CurrentSlot() {
-			continue
-		}
-		if helpers.IsAggregated(a) {
-			if err := s.cfg.AttPool.SaveAggregatedAttestation(a); err != nil {
-				return err
-			}
-		} else {
-			if err := s.cfg.AttPool.SaveUnaggregatedAttestation(a); err != nil {
-				return err
-			}
-		}
-		saveOrphanedAttCount.Inc()
-	}
-
-	return nil
-}
--- a/beacon-chain/blockchain/head_sync_committee_info.go
+++ b/beacon-chain/blockchain/head_sync_committee_info.go
@@ -1,172 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/async"
-	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/signing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/config/params"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/time/slots"
-)
-
-// Initialize the state cache for sync committees.
-var syncCommitteeHeadStateCache = cache.NewSyncCommitteeHeadState()
-
-// HeadSyncCommitteeFetcher is the interface that wraps the head sync committee related functions.
-// The head sync committee functions return callers sync committee indices and public keys with respect to current head state.
-type HeadSyncCommitteeFetcher interface {
-	HeadSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error)
-	HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot, committeeIndex types.CommitteeIndex) ([][]byte, error)
-}
-
-// HeadDomainFetcher is the interface that wraps the head sync domain related functions.
-// The head sync committee domain functions return callers domain data with respect to slot and head state.
-type HeadDomainFetcher interface {
-	HeadSyncCommitteeDomain(ctx context.Context, slot types.Slot) ([]byte, error)
-	HeadSyncSelectionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error)
-	HeadSyncContributionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error)
-}
-
-// HeadSyncCommitteeDomain returns the head sync committee domain using current head state advanced up to `slot`.
-func (s *Service) HeadSyncCommitteeDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
-	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainSyncCommittee)
-}
-
-// HeadSyncSelectionProofDomain returns the head sync committee domain using current head state advanced up to `slot`.
-func (s *Service) HeadSyncSelectionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
-	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainSyncCommitteeSelectionProof)
-}
-
-// HeadSyncContributionProofDomain returns the head sync committee domain using current head state advanced up to `slot`.
-func (s *Service) HeadSyncContributionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
-	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainContributionAndProof)
-}
-
-// HeadSyncCommitteeIndices returns the sync committee index position using the head state. Input `slot` is taken in consideration
-// where validator's duty for `slot - 1` is used for block inclusion in `slot`. That means when a validator is at epoch boundary
-// across EPOCHS_PER_SYNC_COMMITTEE_PERIOD then the valiator will be considered using next period sync committee.
-//
-// Spec definition:
-// Being assigned to a sync committee for a given slot means that the validator produces and broadcasts signatures for slot - 1 for inclusion in slot.
-// This means that when assigned to an epoch sync committee signatures must be produced and broadcast for slots on range
-// [compute_start_slot_at_epoch(epoch) - 1, compute_start_slot_at_epoch(epoch) + SLOTS_PER_EPOCH - 1)
-// rather than for the range
-// [compute_start_slot_at_epoch(epoch), compute_start_slot_at_epoch(epoch) + SLOTS_PER_EPOCH)
-func (s *Service) HeadSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
-	nextSlotEpoch := slots.ToEpoch(slot + 1)
-	currentEpoch := slots.ToEpoch(slot)
-
-	switch {
-	case slots.SyncCommitteePeriod(nextSlotEpoch) == slots.SyncCommitteePeriod(currentEpoch):
-		return s.headCurrentSyncCommitteeIndices(ctx, index, slot)
-	// At sync committee period boundary, validator should sample the next epoch sync committee.
-	case slots.SyncCommitteePeriod(nextSlotEpoch) == slots.SyncCommitteePeriod(currentEpoch)+1:
-		return s.headNextSyncCommitteeIndices(ctx, index, slot)
-	default:
-		// Impossible condition.
-		return nil, errors.New("could get calculate sync subcommittee based on the period")
-	}
-}
-
-// headCurrentSyncCommitteeIndices returns the input validator `index`'s position indices in the current sync committee with respect to `slot`.
-// Head state advanced up to `slot` is used for calculation.
-func (s *Service) headCurrentSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
-	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
-	if err != nil {
-		return nil, err
-	}
-	return helpers.CurrentPeriodSyncSubcommitteeIndices(headState, index)
-}
-
-// headNextSyncCommitteeIndices returns the input validator `index`'s position indices in the next sync committee with respect to `slot`.
-// Head state advanced up to `slot` is used for calculation.
-func (s *Service) headNextSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
-	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
-	if err != nil {
-		return nil, err
-	}
-	return helpers.NextPeriodSyncSubcommitteeIndices(headState, index)
-}
-
-// HeadSyncCommitteePubKeys returns the head sync committee public keys with respect to `slot` and subcommittee index `committeeIndex`.
-// Head state advanced up to `slot` is used for calculation.
-func (s *Service) HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot, committeeIndex types.CommitteeIndex) ([][]byte, error) {
-	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
-	if err != nil {
-		return nil, err
-	}
-
-	nextSlotEpoch := slots.ToEpoch(headState.Slot() + 1)
-	currEpoch := slots.ToEpoch(headState.Slot())
-
-	var syncCommittee *ethpb.SyncCommittee
-	if currEpoch == nextSlotEpoch || slots.SyncCommitteePeriod(currEpoch) == slots.SyncCommitteePeriod(nextSlotEpoch) {
-		syncCommittee, err = headState.CurrentSyncCommittee()
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		syncCommittee, err = headState.NextSyncCommittee()
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	return altair.SyncSubCommitteePubkeys(syncCommittee, committeeIndex)
-}
-
-// returns calculated domain using input `domain` and `slot`.
-func (s *Service) domainWithHeadState(ctx context.Context, slot types.Slot, domain [4]byte) ([]byte, error) {
-	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
-	if err != nil {
-		return nil, err
-	}
-	return signing.Domain(headState.Fork(), slots.ToEpoch(headState.Slot()), domain, headState.GenesisValidatorsRoot())
-}
-
-// returns the head state that is advanced up to `slot`. It utilizes the cache `syncCommitteeHeadState` by retrieving using `slot` as key.
-// For the cache miss, it processes head state up to slot and fill the cache with `slot` as key.
-func (s *Service) getSyncCommitteeHeadState(ctx context.Context, slot types.Slot) (state.BeaconState, error) {
-	var headState state.BeaconState
-	var err error
-	mLock := async.NewMultilock(fmt.Sprintf("%s-%d", "syncHeadState", slot))
-	mLock.Lock()
-	defer mLock.Unlock()
-
-	// If there's already a head state exists with the request slot, we don't need to process slots.
-	cachedState, err := syncCommitteeHeadStateCache.Get(slot)
-	switch {
-	case err == nil:
-		syncHeadStateHit.Inc()
-		headState = cachedState
-		return headState, nil
-	case errors.Is(err, cache.ErrNotFound):
-		headState, err = s.HeadState(ctx)
-		if err != nil {
-			return nil, err
-		}
-		if headState == nil || headState.IsNil() {
-			return nil, errors.New("nil state")
-		}
-		headState, err = transition.ProcessSlotsIfPossible(ctx, headState, slot)
-		if err != nil {
-			return nil, err
-		}
-		syncHeadStateMiss.Inc()
-		err = syncCommitteeHeadStateCache.Put(slot, headState)
-		return headState, err
-	default:
-		// In the event, we encounter another error
-		// we return it.
-		return nil, err
-	}
-}
--- a/beacon-chain/blockchain/head_sync_committee_info_test.go
+++ b/beacon-chain/blockchain/head_sync_committee_info_test.go
@@ -1,176 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"testing"
-
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/signing"
-	dbtest "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	"github.com/prysmaticlabs/prysm/time/slots"
-)
-
-func TestService_headSyncCommitteeFetcher_Errors(t *testing.T) {
-	beaconDB := dbtest.SetupDB(t)
-	c := &Service{
-		cfg: &config{
-			StateGen: stategen.New(beaconDB),
-		},
-	}
-	c.head = &head{}
-	_, err := c.headCurrentSyncCommitteeIndices(context.Background(), types.ValidatorIndex(0), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.headNextSyncCommitteeIndices(context.Background(), types.ValidatorIndex(0), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.HeadSyncCommitteePubKeys(context.Background(), types.Slot(0), types.CommitteeIndex(0))
-	require.ErrorContains(t, "nil state", err)
-}
-
-func TestService_HeadDomainFetcher_Errors(t *testing.T) {
-	beaconDB := dbtest.SetupDB(t)
-	c := &Service{
-		cfg: &config{
-			StateGen: stategen.New(beaconDB),
-		},
-	}
-	c.head = &head{}
-	_, err := c.HeadSyncCommitteeDomain(context.Background(), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.HeadSyncSelectionProofDomain(context.Background(), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.HeadSyncSelectionProofDomain(context.Background(), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-}
-
-func TestService_HeadSyncCommitteeIndices(t *testing.T) {
-	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	// Current period
-	slot := 2*uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	a, err := c.HeadSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
-	require.NoError(t, err)
-
-	// Current period where slot-2 across EPOCHS_PER_SYNC_COMMITTEE_PERIOD
-	slot = 3*uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) - 2
-	b, err := c.HeadSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
-	require.NoError(t, err)
-	require.DeepEqual(t, a, b)
-
-	// Next period where slot-1 across EPOCHS_PER_SYNC_COMMITTEE_PERIOD
-	slot = 3*uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) - 1
-	b, err = c.HeadSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
-	require.NoError(t, err)
-	require.DeepNotEqual(t, a, b)
-}
-
-func TestService_headCurrentSyncCommitteeIndices(t *testing.T) {
-	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	// Process slot up to `EpochsPerSyncCommitteePeriod` so it can `ProcessSyncCommitteeUpdates`.
-	slot := uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	indices, err := c.headCurrentSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
-	require.NoError(t, err)
-
-	// NextSyncCommittee becomes CurrentSyncCommittee so it should be empty by default.
-	require.Equal(t, 0, len(indices))
-}
-
-func TestService_headNextSyncCommitteeIndices(t *testing.T) {
-	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	// Process slot up to `EpochsPerSyncCommitteePeriod` so it can `ProcessSyncCommitteeUpdates`.
-	slot := uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	indices, err := c.headNextSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
-	require.NoError(t, err)
-
-	// NextSyncCommittee should be be empty after `ProcessSyncCommitteeUpdates`. Validator should get indices.
-	require.NotEqual(t, 0, len(indices))
-}
-
-func TestService_HeadSyncCommitteePubKeys(t *testing.T) {
-	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	// Process slot up to 2 * `EpochsPerSyncCommitteePeriod` so it can run `ProcessSyncCommitteeUpdates` twice.
-	slot := uint64(2*params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	pubkeys, err := c.HeadSyncCommitteePubKeys(context.Background(), types.Slot(slot), 0)
-	require.NoError(t, err)
-
-	// Any subcommittee should match the subcommittee size.
-	subCommitteeSize := params.BeaconConfig().SyncCommitteeSize / params.BeaconConfig().SyncCommitteeSubnetCount
-	require.Equal(t, int(subCommitteeSize), len(pubkeys))
-}
-
-func TestService_HeadSyncCommitteeDomain(t *testing.T) {
-	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	wanted, err := signing.Domain(s.Fork(), slots.ToEpoch(s.Slot()), params.BeaconConfig().DomainSyncCommittee, s.GenesisValidatorsRoot())
-	require.NoError(t, err)
-
-	d, err := c.HeadSyncCommitteeDomain(context.Background(), 0)
-	require.NoError(t, err)
-
-	require.DeepEqual(t, wanted, d)
-}
-
-func TestService_HeadSyncContributionProofDomain(t *testing.T) {
-	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	wanted, err := signing.Domain(s.Fork(), slots.ToEpoch(s.Slot()), params.BeaconConfig().DomainContributionAndProof, s.GenesisValidatorsRoot())
-	require.NoError(t, err)
-
-	d, err := c.HeadSyncContributionProofDomain(context.Background(), 0)
-	require.NoError(t, err)
-
-	require.DeepEqual(t, wanted, d)
-}
-
-func TestService_HeadSyncSelectionProofDomain(t *testing.T) {
-	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
-	c.head = &head{state: s}
-
-	wanted, err := signing.Domain(s.Fork(), slots.ToEpoch(s.Slot()), params.BeaconConfig().DomainSyncCommitteeSelectionProof, s.GenesisValidatorsRoot())
-	require.NoError(t, err)
-
-	d, err := c.HeadSyncSelectionProofDomain(context.Background(), 0)
-	require.NoError(t, err)
-
-	require.DeepEqual(t, wanted, d)
-}
-
-func TestSyncCommitteeHeadStateCache_RoundTrip(t *testing.T) {
-	c := syncCommitteeHeadStateCache
-	t.Cleanup(func() {
-		syncCommitteeHeadStateCache = cache.NewSyncCommitteeHeadState()
-	})
-	beaconState, _ := util.DeterministicGenesisStateAltair(t, 100)
-	require.NoError(t, beaconState.SetSlot(100))
-	cachedState, err := c.Get(101)
-	require.ErrorContains(t, cache.ErrNotFound.Error(), err)
-	require.Equal(t, nil, cachedState)
-	require.NoError(t, c.Put(101, beaconState))
-	cachedState, err = c.Get(101)
-	require.NoError(t, err)
-	require.DeepEqual(t, beaconState, cachedState)
-}
--- a/beacon-chain/blockchain/head_test.go
+++ b/beacon-chain/blockchain/head_test.go
@@ -4,22 +4,18 @@ import (
 	"bytes"
 	"context"
 	"testing"
-	"time"

 	types "github.com/prysmaticlabs/eth2-types"
 	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/config/features"
-	"github.com/prysmaticlabs/prysm/config/params"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	ethpbv1 "github.com/prysmaticlabs/prysm/proto/eth/v1"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

@@ -40,33 +36,31 @@ func TestSaveHead_Different(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	service := setupBeaconChain(t, beaconDB)

-	util.NewBeaconBlock()
-	oldBlock, err := wrapper.WrappedSignedBeaconBlock(
-		util.NewBeaconBlock(),
-	)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), oldBlock))
-	oldRoot, err := oldBlock.Block().HashTreeRoot()
-	require.NoError(t, err)
+	oldRoot := [32]byte{'A'}
 	service.head = &head{
-		slot:  0,
-		root:  oldRoot,
-		block: oldBlock,
+		slot: 0,
+		root: oldRoot,
+		block: interfaces.WrappedPhase0SignedBeaconBlock(
+			&ethpb.SignedBeaconBlock{
+				Block: &ethpb.BeaconBlock{
+					Slot:      0,
+					StateRoot: make([]byte, 32),
+				},
+			},
+		),
 	}

-	newHeadSignedBlock := util.NewBeaconBlock()
+	newHeadSignedBlock := testutil.NewBeaconBlock()
 	newHeadSignedBlock.Block.Slot = 1
 	newHeadBlock := newHeadSignedBlock.Block

-	wsb, err := wrapper.WrappedSignedBeaconBlock(newHeadSignedBlock)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), interfaces.WrappedPhase0SignedBeaconBlock(newHeadSignedBlock)))
 	newRoot, err := newHeadBlock.HashTreeRoot()
 	require.NoError(t, err)
-	headState, err := util.NewBeaconState()
+	headState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, headState.SetSlot(1))
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Slot: 1, Root: newRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}))
 	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), headState, newRoot))
 	require.NoError(t, service.saveHead(context.Background(), newRoot))

@@ -85,34 +79,33 @@ func TestSaveHead_Different_Reorg(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	service := setupBeaconChain(t, beaconDB)

-	oldBlock, err := wrapper.WrappedSignedBeaconBlock(
-		util.NewBeaconBlock(),
-	)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), oldBlock))
-	oldRoot, err := oldBlock.Block().HashTreeRoot()
-	require.NoError(t, err)
+	oldRoot := [32]byte{'A'}
 	service.head = &head{
-		slot:  0,
-		root:  oldRoot,
-		block: oldBlock,
+		slot: 0,
+		root: oldRoot,
+		block: interfaces.WrappedPhase0SignedBeaconBlock(
+			&ethpb.SignedBeaconBlock{
+				Block: &ethpb.BeaconBlock{
+					Slot:      0,
+					StateRoot: make([]byte, 32),
+				},
+			},
+		),
 	}

 	reorgChainParent := [32]byte{'B'}
-	newHeadSignedBlock := util.NewBeaconBlock()
+	newHeadSignedBlock := testutil.NewBeaconBlock()
 	newHeadSignedBlock.Block.Slot = 1
 	newHeadSignedBlock.Block.ParentRoot = reorgChainParent[:]
 	newHeadBlock := newHeadSignedBlock.Block

-	wsb, err := wrapper.WrappedSignedBeaconBlock(newHeadSignedBlock)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), interfaces.WrappedPhase0SignedBeaconBlock(newHeadSignedBlock)))
 	newRoot, err := newHeadBlock.HashTreeRoot()
 	require.NoError(t, err)
-	headState, err := util.NewBeaconState()
+	headState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, headState.SetSlot(1))
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Slot: 1, Root: newRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}))
 	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), headState, newRoot))
 	require.NoError(t, service.saveHead(context.Background(), newRoot))

@@ -131,49 +124,44 @@ func TestSaveHead_Different_Reorg(t *testing.T) {
 func TestCacheJustifiedStateBalances_CanCache(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	service := setupBeaconChain(t, beaconDB)
-	ctx := context.Background()

-	state, _ := util.DeterministicGenesisState(t, 100)
+	state, _ := testutil.DeterministicGenesisState(t, 100)
 	r := [32]byte{'a'}
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: r[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Root: r[:]}))
 	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), state, r))
-	balances, err := service.justifiedBalances.get(ctx, r)
-	require.NoError(t, err)
-	require.DeepEqual(t, balances, state.Balances(), "Incorrect justified balances")
+	require.NoError(t, service.cacheJustifiedStateBalances(context.Background(), r))
+	require.DeepEqual(t, service.getJustifiedBalances(), state.Balances(), "Incorrect justified balances")
 }

 func TestUpdateHead_MissingJustifiedRoot(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	service := setupBeaconChain(t, beaconDB)

-	b := util.NewBeaconBlock()
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), wsb))
+	b := testutil.NewBeaconBlock()
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), interfaces.WrappedPhase0SignedBeaconBlock(b)))
 	r, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)

-	service.store.SetJustifiedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{})
-	service.store.SetBestJustifiedCheckpt(&ethpb.Checkpoint{})
-	headRoot, err := service.updateHead(context.Background(), []uint64{})
-	require.NoError(t, err)
-	require.NoError(t, service.saveHead(context.Background(), headRoot))
+	service.justifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.finalizedCheckpt = &ethpb.Checkpoint{}
+	service.bestJustifiedCheckpt = &ethpb.Checkpoint{}
+
+	require.NoError(t, service.updateHead(context.Background(), []uint64{}))
 }

 func Test_notifyNewHeadEvent(t *testing.T) {
 	t.Run("genesis_state_root", func(t *testing.T) {
-		bState, _ := util.DeterministicGenesisState(t, 10)
+		bState, _ := testutil.DeterministicGenesisState(t, 10)
 		notifier := &mock.MockStateNotifier{RecordEvents: true}
 		srv := &Service{
-			cfg: &config{
+			cfg: &Config{
 				StateNotifier: notifier,
 			},
-			originBlockRoot: [32]byte{1},
+			genesisRoot: [32]byte{1},
 		}
 		newHeadStateRoot := [32]byte{2}
 		newHeadRoot := [32]byte{3}
-		err := srv.notifyNewHeadEvent(context.Background(), 1, bState, newHeadStateRoot[:], newHeadRoot[:])
+		err := srv.notifyNewHeadEvent(1, bState, newHeadStateRoot[:], newHeadRoot[:])
 		require.NoError(t, err)
 		events := notifier.ReceivedEvents()
 		require.Equal(t, 1, len(events))
@@ -185,30 +173,30 @@ func Test_notifyNewHeadEvent(t *testing.T) {
 			Block:                     newHeadRoot[:],
 			State:                     newHeadStateRoot[:],
 			EpochTransition:           false,
-			PreviousDutyDependentRoot: srv.originBlockRoot[:],
-			CurrentDutyDependentRoot:  srv.originBlockRoot[:],
+			PreviousDutyDependentRoot: srv.genesisRoot[:],
+			CurrentDutyDependentRoot:  srv.genesisRoot[:],
 		}
 		require.DeepSSZEqual(t, wanted, eventHead)
 	})
 	t.Run("non_genesis_values", func(t *testing.T) {
-		bState, _ := util.DeterministicGenesisState(t, 10)
+		bState, _ := testutil.DeterministicGenesisState(t, 10)
 		notifier := &mock.MockStateNotifier{RecordEvents: true}
 		genesisRoot := [32]byte{1}
 		srv := &Service{
-			cfg: &config{
+			cfg: &Config{
 				StateNotifier: notifier,
 			},
-			originBlockRoot: genesisRoot,
+			genesisRoot: genesisRoot,
 		}
-		epoch1Start, err := slots.EpochStart(1)
+		epoch1Start, err := helpers.StartSlot(1)
 		require.NoError(t, err)
-		epoch2Start, err := slots.EpochStart(1)
+		epoch2Start, err := helpers.StartSlot(1)
 		require.NoError(t, err)
 		require.NoError(t, bState.SetSlot(epoch1Start))

 		newHeadStateRoot := [32]byte{2}
 		newHeadRoot := [32]byte{3}
-		err = srv.notifyNewHeadEvent(context.Background(), epoch2Start, bState, newHeadStateRoot[:], newHeadRoot[:])
+		err = srv.notifyNewHeadEvent(epoch2Start, bState, newHeadStateRoot[:], newHeadRoot[:])
 		require.NoError(t, err)
 		events := notifier.ReceivedEvents()
 		require.Equal(t, 1, len(events))
@@ -219,106 +207,10 @@ func Test_notifyNewHeadEvent(t *testing.T) {
 			Slot:                      epoch2Start,
 			Block:                     newHeadRoot[:],
 			State:                     newHeadStateRoot[:],
-			EpochTransition:           true,
+			EpochTransition:           false,
 			PreviousDutyDependentRoot: genesisRoot[:],
 			CurrentDutyDependentRoot:  make([]byte, 32),
 		}
 		require.DeepSSZEqual(t, wanted, eventHead)
 	})
 }
-
-func TestSaveOrphanedAtts(t *testing.T) {
-	resetCfg := features.InitWithReset(&features.Flags{
-		CorrectlyInsertOrphanedAtts: true,
-	})
-	defer resetCfg()
-
-	genesis, keys := util.DeterministicGenesisState(t, 64)
-	b, err := util.GenerateFullBlock(genesis, keys, util.DefaultBlockGenConfig(), 1)
-	assert.NoError(t, err)
-	r, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	service := setupBeaconChain(t, beaconDB)
-	service.genesisTime = time.Now()
-
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
-	require.NoError(t, service.saveOrphanedAtts(ctx, r))
-
-	require.Equal(t, len(b.Block.Body.Attestations), service.cfg.AttPool.AggregatedAttestationCount())
-	savedAtts := service.cfg.AttPool.AggregatedAttestations()
-	atts := b.Block.Body.Attestations
-	require.DeepSSZEqual(t, atts, savedAtts)
-}
-
-func TestSaveOrphanedAtts_CanFilter(t *testing.T) {
-	resetCfg := features.InitWithReset(&features.Flags{
-		CorrectlyInsertOrphanedAtts: true,
-	})
-	defer resetCfg()
-
-	genesis, keys := util.DeterministicGenesisState(t, 64)
-	b, err := util.GenerateFullBlock(genesis, keys, util.DefaultBlockGenConfig(), 1)
-	assert.NoError(t, err)
-	r, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	service := setupBeaconChain(t, beaconDB)
-	service.genesisTime = time.Now().Add(time.Duration(-1*int64(params.BeaconConfig().SlotsPerEpoch+1)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)
-
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
-	require.NoError(t, service.saveOrphanedAtts(ctx, r))
-
-	require.Equal(t, 0, service.cfg.AttPool.AggregatedAttestationCount())
-	savedAtts := service.cfg.AttPool.AggregatedAttestations()
-	atts := b.Block.Body.Attestations
-	require.DeepNotSSZEqual(t, atts, savedAtts)
-}
-
-func TestUpdateHead_noSavedChanges(t *testing.T) {
-	ctx := context.Background()
-
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New(0, 0)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	bellatrixBlk, err := wrapper.WrappedSignedBeaconBlock(util.NewBeaconBlockBellatrix())
-	require.NoError(t, err)
-	bellatrixBlkRoot, err := bellatrixBlk.Block().HashTreeRoot()
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, bellatrixBlk))
-	fcp := &ethpb.Checkpoint{
-		Root:  bellatrixBlkRoot[:],
-		Epoch: 1,
-	}
-	service.store.SetFinalizedCheckpt(fcp)
-	service.store.SetJustifiedCheckpt(fcp)
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, bellatrixBlkRoot))
-
-	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
-	require.NoError(t, beaconDB.SaveState(ctx, bellatrixState, bellatrixBlkRoot))
-	service.cfg.StateGen.SaveFinalizedState(0, bellatrixBlkRoot, bellatrixState)
-
-	headRoot := service.headRoot()
-	require.Equal(t, [32]byte{}, headRoot)
-
-	newRoot, err := service.updateHead(ctx, []uint64{1, 2})
-	require.NoError(t, err)
-	require.NotEqual(t, headRoot, newRoot)
-	require.Equal(t, headRoot, service.headRoot())
-}
--- a/beacon-chain/blockchain/info.go
+++ b/beacon-chain/blockchain/info.go
@@ -0,0 +1,99 @@
+package blockchain
+
+import (
+	"encoding/hex"
+	"fmt"
+	"net/http"
+
+	"github.com/emicklei/dot"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+const template = `<html>
+<head>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/viz.js/2.1.2/viz.js"></script>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/viz.js/2.1.2/full.render.js"></script>
+<body>
+    <script type="application/javascript">
+        var graph = ` + "`%s`;" + `
+        var viz = new Viz();
+        viz.renderSVGElement(graph) // reading the graph.
+            .then(function(element) {
+                document.body.appendChild(element); // appends to document.
+            })
+            .catch(error => {
+                // Create a new Viz instance (@see Caveats page for more info)
+                viz = new Viz();
+                // Possibly display the error
+                console.error(error);
+            });
+    </script>
+</head>
+</body>
+</html>`
+
+// TreeHandler is a handler to serve /tree page in metrics.
+func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
+	headState, err := s.HeadState(r.Context())
+	if err != nil {
+		log.WithError(err).Error("Could not get head state")
+		return
+	}
+	if headState == nil || headState.IsNil() {
+		if _, err := w.Write([]byte("Unavailable during initial syncing")); err != nil {
+			log.WithError(err).Error("Failed to render p2p info page")
+		}
+	}
+
+	nodes := s.cfg.ForkChoiceStore.Nodes()
+
+	graph := dot.NewGraph(dot.Directed)
+	graph.Attr("rankdir", "RL")
+	graph.Attr("labeljust", "l")
+
+	dotNodes := make([]*dot.Node, len(nodes))
+	avgBalance := uint64(averageBalance(headState.Balances()))
+
+	for i := len(nodes) - 1; i >= 0; i-- {
+		// Construct label for each node.
+		slot := fmt.Sprintf("%d", nodes[i].Slot())
+		weight := fmt.Sprintf("%d", nodes[i].Weight()/1e9) // Convert unit Gwei to unit ETH.
+		votes := fmt.Sprintf("%d", nodes[i].Weight()/1e9/avgBalance)
+		index := fmt.Sprintf("%d", i)
+		g := nodes[i].Graffiti()
+		graffiti := hex.EncodeToString(g[:8])
+		label := "slot: " + slot + "\n votes: " + votes + "\n weight: " + weight + "\n graffiti: " + graffiti
+		var dotN dot.Node
+		if nodes[i].Parent() != ^uint64(0) {
+			dotN = graph.Node(index).Box().Attr("label", label)
+		}
+
+		if nodes[i].Slot() == s.HeadSlot() &&
+			nodes[i].BestDescendant() == ^uint64(0) &&
+			nodes[i].Parent() != ^uint64(0) {
+			dotN = dotN.Attr("color", "green")
+		}
+
+		dotNodes[i] = &dotN
+	}
+
+	for i := len(nodes) - 1; i >= 0; i-- {
+		if nodes[i].Parent() != ^uint64(0) && nodes[i].Parent() < uint64(len(dotNodes)) {
+			graph.Edge(*dotNodes[i], *dotNodes[nodes[i].Parent()])
+		}
+	}
+
+	w.WriteHeader(http.StatusOK)
+	w.Header().Set("Content-Type", "text/html")
+	if _, err := fmt.Fprintf(w, template, graph.String()); err != nil {
+		log.WithError(err).Error("Failed to render p2p info page")
+	}
+}
+
+func averageBalance(balances []uint64) float64 {
+	total := uint64(0)
+	for i := 0; i < len(balances); i++ {
+		total += balances[i]
+	}
+	return float64(total) / float64(len(balances)) / float64(params.BeaconConfig().GweiPerEth)
+}
--- a/beacon-chain/blockchain/info_test.go
+++ b/beacon-chain/blockchain/info_test.go
@@ -0,0 +1,49 @@
+package blockchain
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestService_TreeHandler(t *testing.T) {
+	req, err := http.NewRequest("GET", "/tree", nil)
+	require.NoError(t, err)
+
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	headState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetBalances([]uint64{params.BeaconConfig().GweiPerEth}))
+	cfg := &Config{
+		BeaconDB: beaconDB,
+		ForkChoiceStore: protoarray.New(
+			0, // justifiedEpoch
+			0, // finalizedEpoch
+			[32]byte{'a'},
+		),
+		StateGen: stategen.New(beaconDB),
+	}
+	s, err := NewService(ctx, cfg)
+	require.NoError(t, err)
+	require.NoError(t, s.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, [32]byte{'a'}, [32]byte{'g'}, [32]byte{'c'}, 0, 0))
+	require.NoError(t, s.cfg.ForkChoiceStore.ProcessBlock(ctx, 1, [32]byte{'b'}, [32]byte{'a'}, [32]byte{'c'}, 0, 0))
+	s.setHead([32]byte{'a'}, interfaces.WrappedPhase0SignedBeaconBlock(testutil.NewBeaconBlock()), headState)
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(s.TreeHandler)
+
+	handler.ServeHTTP(rr, req)
+
+	assert.Equal(t, http.StatusOK, rr.Code)
+}
--- a/beacon-chain/blockchain/init_sync_process_block.go
+++ b/beacon-chain/blockchain/init_sync_process_block.go
@@ -1,11 +1,11 @@
 package blockchain

 import (
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
 )

 // This saves a beacon block to the initial sync blocks cache.
-func (s *Service) saveInitSyncBlock(r [32]byte, b block.SignedBeaconBlock) {
+func (s *Service) saveInitSyncBlock(r [32]byte, b interfaces.SignedBeaconBlock) {
 	s.initSyncBlocksLock.Lock()
 	defer s.initSyncBlocksLock.Unlock()
 	s.initSyncBlocks[r] = b
@@ -22,7 +22,7 @@ func (s *Service) hasInitSyncBlock(r [32]byte) bool {

 // This retrieves a beacon block from the initial sync blocks cache using the root of
 // the block.
-func (s *Service) getInitSyncBlock(r [32]byte) block.SignedBeaconBlock {
+func (s *Service) getInitSyncBlock(r [32]byte) interfaces.SignedBeaconBlock {
 	s.initSyncBlocksLock.RLock()
 	defer s.initSyncBlocksLock.RUnlock()
 	b := s.initSyncBlocks[r]
@@ -31,11 +31,11 @@ func (s *Service) getInitSyncBlock(r [32]byte) block.SignedBeaconBlock {

 // This retrieves all the beacon blocks from the initial sync blocks cache, the returned
 // blocks are unordered.
-func (s *Service) getInitSyncBlocks() []block.SignedBeaconBlock {
+func (s *Service) getInitSyncBlocks() []interfaces.SignedBeaconBlock {
 	s.initSyncBlocksLock.RLock()
 	defer s.initSyncBlocksLock.RUnlock()

-	blks := make([]block.SignedBeaconBlock, 0, len(s.initSyncBlocks))
+	blks := make([]interfaces.SignedBeaconBlock, 0, len(s.initSyncBlocks))
 	for _, b := range s.initSyncBlocks {
 		blks = append(blks, b)
 	}
@@ -46,5 +46,5 @@ func (s *Service) getInitSyncBlocks() []block.SignedBeaconBlock {
 func (s *Service) clearInitSyncBlocks() {
 	s.initSyncBlocksLock.Lock()
 	defer s.initSyncBlocksLock.Unlock()
-	s.initSyncBlocks = make(map[[32]byte]block.SignedBeaconBlock)
+	s.initSyncBlocks = make(map[[32]byte]interfaces.SignedBeaconBlock)
 }
--- a/beacon-chain/blockchain/init_test.go
+++ b/beacon-chain/blockchain/init_test.go
@@ -1,7 +1,7 @@
 package blockchain

 import (
-	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )

 func init() {
--- a/beacon-chain/blockchain/log.go
+++ b/beacon-chain/blockchain/log.go
@@ -5,21 +5,19 @@ import (
 	"fmt"
 	"time"

-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/runtime/version"
-	prysmTime "github.com/prysmaticlabs/prysm/time"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 	"github.com/sirupsen/logrus"
 )

 var log = logrus.WithField("prefix", "blockchain")

 // logs state transition related data every slot.
-func logStateTransitionData(b block.BeaconBlock) error {
-	log := log.WithField("slot", b.Slot())
+func logStateTransitionData(b interfaces.BeaconBlock) {
+	log := log.WithField("slot", b.Slot)
 	if len(b.Body().Attestations()) > 0 {
 		log = log.WithField("attestations", len(b.Body().Attestations()))
 	}
@@ -35,27 +33,11 @@ func logStateTransitionData(b block.BeaconBlock) error {
 	if len(b.Body().VoluntaryExits()) > 0 {
 		log = log.WithField("voluntaryExits", len(b.Body().VoluntaryExits()))
 	}
-	if b.Version() == version.Altair || b.Version() == version.Bellatrix {
-		agg, err := b.Body().SyncAggregate()
-		if err != nil {
-			return err
-		}
-		log = log.WithField("syncBitsCount", agg.SyncCommitteeBits.Count())
-	}
-	if b.Version() == version.Bellatrix {
-		p, err := b.Body().ExecutionPayload()
-		if err != nil {
-			return err
-		}
-		log = log.WithField("payloadHash", fmt.Sprintf("%#x", bytesutil.Trunc(p.BlockHash)))
-		log = log.WithField("txCount", len(p.Transactions))
-	}
 	log.Info("Finished applying state transition")
-	return nil
 }

-func logBlockSyncStatus(block block.BeaconBlock, blockRoot [32]byte, finalized *ethpb.Checkpoint, receivedTime time.Time, genesisTime uint64) error {
-	startTime, err := slots.ToTime(genesisTime, block.Slot())
+func logBlockSyncStatus(block interfaces.BeaconBlock, blockRoot [32]byte, finalized *ethpb.Checkpoint, receivedTime time.Time, genesisTime uint64) error {
+	startTime, err := helpers.SlotToTime(genesisTime, block.Slot())
 	if err != nil {
 		return err
 	}
@@ -63,16 +45,14 @@ func logBlockSyncStatus(block block.BeaconBlock, blockRoot [32]byte, finalized *
 		"slot":           block.Slot(),
 		"slotInEpoch":    block.Slot() % params.BeaconConfig().SlotsPerEpoch,
 		"block":          fmt.Sprintf("0x%s...", hex.EncodeToString(blockRoot[:])[:8]),
-		"epoch":          slots.ToEpoch(block.Slot()),
+		"epoch":          helpers.SlotToEpoch(block.Slot()),
 		"finalizedEpoch": finalized.Epoch,
 		"finalizedRoot":  fmt.Sprintf("0x%s...", hex.EncodeToString(finalized.Root)[:8]),
-		"parentRoot":     fmt.Sprintf("0x%s...", hex.EncodeToString(block.ParentRoot())[:8]),
-		"version":        version.String(block.Version()),
 	}).Info("Synced new block")
 	log.WithFields(logrus.Fields{
 		"slot":                      block.Slot,
-		"sinceSlotStartTime":        prysmTime.Now().Sub(startTime),
-		"chainServiceProcessedTime": prysmTime.Now().Sub(receivedTime),
+		"sinceSlotStartTime":        timeutils.Now().Sub(startTime),
+		"chainServiceProcessedTime": timeutils.Now().Sub(receivedTime),
 	}).Debug("Sync new block times")
 	return nil
 }
--- a/beacon-chain/blockchain/log_test.go
+++ b/beacon-chain/blockchain/log_test.go
@@ -3,79 +3,61 @@ package blockchain
 import (
 	"testing"

-	enginev1 "github.com/prysmaticlabs/prysm/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/require"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

 func Test_logStateTransitionData(t *testing.T) {
-	payloadBlk := &ethpb.BeaconBlockBellatrix{
-		Body: &ethpb.BeaconBlockBodyBellatrix{
-			SyncAggregate: &ethpb.SyncAggregate{},
-			ExecutionPayload: &enginev1.ExecutionPayload{
-				BlockHash:    []byte{1, 2, 3},
-				Transactions: [][]byte{{}, {}},
-			},
-		},
-	}
-	wrappedPayloadBlk, err := wrapper.WrappedBeaconBlock(payloadBlk)
-	require.NoError(t, err)
 	tests := []struct {
 		name string
-		b    block.BeaconBlock
+		b    *ethpb.BeaconBlock
 		want string
 	}{
 		{name: "empty block body",
-			b:    wrapper.WrappedPhase0BeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}),
+			b:    &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}},
 			want: "\"Finished applying state transition\" prefix=blockchain slot=0",
 		},
 		{name: "has attestation",
-			b:    wrapper.WrappedPhase0BeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{Attestations: []*ethpb.Attestation{{}}}}),
+			b:    &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{Attestations: []*ethpb.Attestation{{}}}},
 			want: "\"Finished applying state transition\" attestations=1 prefix=blockchain slot=0",
 		},
 		{name: "has deposit",
-			b: wrapper.WrappedPhase0BeaconBlock(
-				&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
-					Attestations: []*ethpb.Attestation{{}},
-					Deposits:     []*ethpb.Deposit{{}}}}),
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				Attestations: []*ethpb.Attestation{{}},
+				Deposits:     []*ethpb.Deposit{{}}}},
 			want: "\"Finished applying state transition\" attestations=1 deposits=1 prefix=blockchain slot=0",
 		},
 		{name: "has attester slashing",
-			b: wrapper.WrappedPhase0BeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
-				AttesterSlashings: []*ethpb.AttesterSlashing{{}}}}),
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				AttesterSlashings: []*ethpb.AttesterSlashing{{}}}},
 			want: "\"Finished applying state transition\" attesterSlashings=1 prefix=blockchain slot=0",
 		},
 		{name: "has proposer slashing",
-			b: wrapper.WrappedPhase0BeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
-				ProposerSlashings: []*ethpb.ProposerSlashing{{}}}}),
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				ProposerSlashings: []*ethpb.ProposerSlashing{{}}}},
 			want: "\"Finished applying state transition\" prefix=blockchain proposerSlashings=1 slot=0",
 		},
 		{name: "has exit",
-			b: wrapper.WrappedPhase0BeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
-				VoluntaryExits: []*ethpb.SignedVoluntaryExit{{}}}}),
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				VoluntaryExits: []*ethpb.SignedVoluntaryExit{{}}}},
 			want: "\"Finished applying state transition\" prefix=blockchain slot=0 voluntaryExits=1",
 		},
 		{name: "has everything",
-			b: wrapper.WrappedPhase0BeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
 				Attestations:      []*ethpb.Attestation{{}},
 				Deposits:          []*ethpb.Deposit{{}},
 				AttesterSlashings: []*ethpb.AttesterSlashing{{}},
 				ProposerSlashings: []*ethpb.ProposerSlashing{{}},
-				VoluntaryExits:    []*ethpb.SignedVoluntaryExit{{}}}}),
+				VoluntaryExits:    []*ethpb.SignedVoluntaryExit{{}}}},
 			want: "\"Finished applying state transition\" attestations=1 attesterSlashings=1 deposits=1 prefix=blockchain proposerSlashings=1 slot=0 voluntaryExits=1",
 		},
-		{name: "has payload",
-			b:    wrappedPayloadBlk,
-			want: "\"Finished applying state transition\" payloadHash=0x010203 prefix=blockchain slot=0 syncBitsCount=0 txCount=2",
-		},
 	}
 	for _, tt := range tests {
 		hook := logTest.NewGlobal()
 		t.Run(tt.name, func(t *testing.T) {
-			require.NoError(t, logStateTransitionData(tt.b))
+			logStateTransitionData(interfaces.WrappedPhase0BeaconBlock(tt.b))
 			require.LogsContain(t, hook, tt.want)
 		})
 	}
--- a/beacon-chain/blockchain/metrics.go
+++ b/beacon-chain/blockchain/metrics.go
@@ -3,18 +3,15 @@ package blockchain
 import (
 	"context"

-	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/altair"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/runtime/version"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )

 var (
@@ -63,10 +60,6 @@ var (
 		Name: "beacon_previous_justified_root",
 		Help: "Previous justified root of the processed state",
 	})
-	activeValidatorCount = promauto.NewGauge(prometheus.GaugeOpts{
-		Name: "beacon_current_active_validators",
-		Help: "Current total active validators",
-	})
 	validatorsCount = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Name: "validator_count",
 		Help: "The total number of validators",
@@ -83,10 +76,6 @@ var (
 		Name: "current_eth1_data_deposit_count",
 		Help: "The current eth1 deposit count in the last processed state eth1data field.",
 	})
-	processedDepositsCount = promauto.NewGauge(prometheus.GaugeOpts{
-		Name: "beacon_processed_deposits_total",
-		Help: "Total number of deposits processed",
-	})
 	stateTrieReferences = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Name: "field_references",
 		Help: "The number of states a particular field is shared with.",
@@ -108,13 +97,9 @@ var (
 		Help: "The total amount of ether, in gwei, that has been used in voting attestation head of previous epoch",
 	})
 	reorgCount = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "beacon_reorgs_total",
+		Name: "beacon_reorg_total",
 		Help: "Count the number of times beacon chain has a reorg",
 	})
-	saveOrphanedAttCount = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "saved_orphaned_att_total",
-		Help: "Count the number of times an orphaned attestation is saved",
-	})
 	attestationInclusionDelay = promauto.NewHistogram(
 		prometheus.HistogramOpts{
 			Name:    "attestation_inclusion_delay_slots",
@@ -122,22 +107,6 @@ var (
 			Buckets: []float64{1, 2, 3, 4, 6, 32, 64},
 		},
 	)
-	syncHeadStateMiss = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "sync_head_state_miss",
-		Help: "The number of sync head state requests that are not present in the cache.",
-	})
-	syncHeadStateHit = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "sync_head_state_hit",
-		Help: "The number of sync head state requests that are present in the cache.",
-	})
-	stateBalanceCacheHit = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "state_balance_cache_hit",
-		Help: "Count the number of state balance cache hits.",
-	})
-	stateBalanceCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "state_balance_cache_miss",
-		Help: "Count the number of state balance cache hits.",
-	})
 )

 // reportSlotMetrics reports slot related metrics.
@@ -152,7 +121,7 @@ func reportSlotMetrics(stateSlot, headSlot, clockSlot types.Slot, finalizedCheck
 }

 // reportEpochMetrics reports epoch related metrics.
-func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconState) error {
+func reportEpochMetrics(ctx context.Context, postState, headState iface.BeaconState) error {
 	currentEpoch := types.Epoch(postState.Slot() / params.BeaconConfig().SlotsPerEpoch)

 	// Validator instances
@@ -210,7 +179,6 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	activeBalance += exitingBalance + slashingBalance
 	activeEffectiveBalance += exitingEffectiveBalance + slashingEffectiveBalance

-	activeValidatorCount.Set(float64(activeInstances))
 	validatorsCount.WithLabelValues("Pending").Set(float64(pendingInstances))
 	validatorsCount.WithLabelValues("Active").Set(float64(activeInstances))
 	validatorsCount.WithLabelValues("Exiting").Set(float64(exitingInstances))
@@ -237,33 +205,15 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	beaconFinalizedEpoch.Set(float64(postState.FinalizedCheckpointEpoch()))
 	beaconFinalizedRoot.Set(float64(bytesutil.ToLowInt64(postState.FinalizedCheckpoint().Root)))
 	currentEth1DataDepositCount.Set(float64(postState.Eth1Data().DepositCount))
-	processedDepositsCount.Set(float64(postState.Eth1DepositIndex() + 1))

-	var b *precompute.Balance
-	var v []*precompute.Validator
-	var err error
-	switch headState.Version() {
-	case version.Phase0:
-		// Validator participation should be viewed on the canonical chain.
-		v, b, err = precompute.New(ctx, headState)
-		if err != nil {
-			return err
-		}
-		_, b, err = precompute.ProcessAttestations(ctx, headState, v, b)
-		if err != nil {
-			return err
-		}
-	case version.Altair, version.Bellatrix:
-		v, b, err = altair.InitializePrecomputeValidators(ctx, headState)
-		if err != nil {
-			return err
-		}
-		_, b, err = altair.ProcessEpochParticipation(ctx, headState, b, v)
-		if err != nil {
-			return err
-		}
-	default:
-		return errors.Errorf("invalid state type provided: %T", headState.InnerStateUnsafe())
+	// Validator participation should be viewed on the canonical chain.
+	v, b, err := precompute.New(ctx, headState)
+	if err != nil {
+		return err
+	}
+	_, b, err = precompute.ProcessAttestations(ctx, headState, v, b)
+	if err != nil {
+		return err
 	}
 	prevEpochActiveBalances.Set(float64(b.ActivePrevEpoch))
 	prevEpochSourceBalances.Set(float64(b.PrevEpochAttested))
@@ -278,7 +228,7 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	return nil
 }

-func reportAttestationInclusion(blk block.BeaconBlock) {
+func reportAttestationInclusion(blk interfaces.BeaconBlock) {
 	for _, att := range blk.Body().Attestations() {
 		attestationInclusionDelay.Observe(float64(blk.Slot() - att.Data.Slot))
 	}
--- a/beacon-chain/blockchain/metrics_test.go
+++ b/beacon-chain/blockchain/metrics_test.go
@@ -4,15 +4,16 @@ import (
 	"context"
 	"testing"

-	eth "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	eth "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestReportEpochMetrics_BadHeadState(t *testing.T) {
-	s, err := util.NewBeaconState()
+	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	h, err := util.NewBeaconState()
+	h, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, h.SetValidators(nil))
 	err = reportEpochMetrics(context.Background(), s, h)
@@ -20,22 +21,22 @@ func TestReportEpochMetrics_BadHeadState(t *testing.T) {
 }

 func TestReportEpochMetrics_BadAttestation(t *testing.T) {
-	s, err := util.NewBeaconState()
+	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	h, err := util.NewBeaconState()
+	h, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	require.NoError(t, h.AppendCurrentEpochAttestations(&eth.PendingAttestation{InclusionDelay: 0}))
+	require.NoError(t, h.AppendCurrentEpochAttestations(&pb.PendingAttestation{InclusionDelay: 0}))
 	err = reportEpochMetrics(context.Background(), s, h)
 	require.ErrorContains(t, "attestation with inclusion delay of 0", err)
 }

 func TestReportEpochMetrics_SlashedValidatorOutOfBound(t *testing.T) {
-	h, _ := util.DeterministicGenesisState(t, 1)
+	h, _ := testutil.DeterministicGenesisState(t, 1)
 	v, err := h.ValidatorAtIndex(0)
 	require.NoError(t, err)
 	v.Slashed = true
 	require.NoError(t, h.UpdateValidatorAtIndex(0, v))
-	require.NoError(t, h.AppendCurrentEpochAttestations(&eth.PendingAttestation{InclusionDelay: 1, Data: util.HydrateAttestationData(&eth.AttestationData{})}))
+	require.NoError(t, h.AppendCurrentEpochAttestations(&pb.PendingAttestation{InclusionDelay: 1, Data: testutil.HydrateAttestationData(&eth.AttestationData{})}))
 	err = reportEpochMetrics(context.Background(), h, h)
 	require.ErrorContains(t, "slot 0 out of bounds", err)
 }
--- a/beacon-chain/blockchain/mock_test.go
+++ b/beacon-chain/blockchain/mock_test.go
@@ -1,50 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"errors"
-	"testing"
-
-	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-)
-
-func testServiceOptsWithDB(t *testing.T) []Option {
-	beaconDB := testDB.SetupDB(t)
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	return []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-}
-
-// warning: only use these opts when you are certain there are no db calls
-// in your code path. this is a lightweight way to satisfy the stategen/beacondb
-// initialization requirements w/o the overhead of db init.
-func testServiceOptsNoDB() []Option {
-	return []Option{
-		withStateBalanceCache(satisfactoryStateBalanceCache()),
-	}
-}
-
-type mockStateByRooter struct {
-	state state.BeaconState
-	err   error
-}
-
-var _ stateByRooter = &mockStateByRooter{}
-
-func (m mockStateByRooter) StateByRoot(_ context.Context, _ [32]byte) (state.BeaconState, error) {
-	return m.state, m.err
-}
-
-// returns an instance of the state balance cache that can be used
-// to satisfy the requirement for one in NewService, but which will
-// always return an error if used.
-func satisfactoryStateBalanceCache() *stateBalanceCache {
-	err := errors.New("satisfactoryStateBalanceCache doesn't perform real caching")
-	return &stateBalanceCache{stateGen: mockStateByRooter{err: err}}
-}
--- a/beacon-chain/blockchain/new_slot.go
+++ b/beacon-chain/blockchain/new_slot.go
@@ -1,72 +0,0 @@
-package blockchain
-
-import (
-	"bytes"
-	"context"
-
-	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/time/slots"
-)
-
-// NewSlot mimics the implementation of `on_tick` in fork choice consensus spec.
-// It resets the proposer boost root in fork choice, and it updates store's justified checkpoint
-// if a better checkpoint on the store's finalized checkpoint chain.
-// This should only be called at the start of every slot interval.
-//
-// Spec pseudocode definition:
-//    # Reset store.proposer_boost_root if this is a new slot
-//    if current_slot > previous_slot:
-//        store.proposer_boost_root = Root()
-//
-//    # Not a new epoch, return
-//    if not (current_slot > previous_slot and compute_slots_since_epoch_start(current_slot) == 0):
-//        return
-//
-//    # Update store.justified_checkpoint if a better checkpoint on the store.finalized_checkpoint chain
-//    if store.best_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
-//        finalized_slot = compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
-//        ancestor_at_finalized_slot = get_ancestor(store, store.best_justified_checkpoint.root, finalized_slot)
-//        if ancestor_at_finalized_slot == store.finalized_checkpoint.root:
-//            store.justified_checkpoint = store.best_justified_checkpoint
-func (s *Service) NewSlot(ctx context.Context, slot types.Slot) error {
-
-	// Reset proposer boost root in fork choice.
-	if err := s.cfg.ForkChoiceStore.ResetBoostedProposerRoot(ctx); err != nil {
-		return errors.Wrap(err, "could not reset boosted proposer root in fork choice")
-	}
-
-	// Return if it's not a new epoch.
-	if !slots.IsEpochStart(slot) {
-		return nil
-	}
-
-	// Update store.justified_checkpoint if a better checkpoint on the store.finalized_checkpoint chain
-	bj := s.store.BestJustifiedCheckpt()
-	if bj == nil {
-		return errNilBestJustifiedInStore
-	}
-	j := s.store.JustifiedCheckpt()
-	if j == nil {
-		return errNilJustifiedInStore
-	}
-	f := s.store.FinalizedCheckpt()
-	if f == nil {
-		return errNilFinalizedInStore
-	}
-	if bj.Epoch > j.Epoch {
-		finalizedSlot, err := slots.EpochStart(f.Epoch)
-		if err != nil {
-			return err
-		}
-		r, err := s.ancestor(ctx, bj.Root, finalizedSlot)
-		if err != nil {
-			return err
-		}
-		if bytes.Equal(r, f.Root) {
-			s.store.SetJustifiedCheckpt(bj)
-		}
-	}
-	return nil
-
-}
--- a/beacon-chain/blockchain/new_slot_test.go
+++ b/beacon-chain/blockchain/new_slot_test.go
@@ -1,100 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"testing"
-
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/blockchain/store"
-	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-func TestService_newSlot(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	fcs := protoarray.New(0, 0, [32]byte{})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	ctx := context.Background()
-
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 0, [32]byte{}, [32]byte{}, [32]byte{}, 0, 0))        // genesis
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 32, [32]byte{'a'}, [32]byte{}, [32]byte{}, 0, 0))    // finalized
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 64, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 0, 0)) // justified
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 96, [32]byte{'c'}, [32]byte{'a'}, [32]byte{}, 0, 0)) // best justified
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 97, [32]byte{'d'}, [32]byte{}, [32]byte{}, 0, 0))    // bad
-
-	type args struct {
-		slot          types.Slot
-		finalized     *ethpb.Checkpoint
-		justified     *ethpb.Checkpoint
-		bestJustified *ethpb.Checkpoint
-		shouldEqual   bool
-	}
-	tests := []struct {
-		name string
-		args args
-	}{
-		{
-			name: "Not epoch boundary. No change",
-			args: args{
-				slot:          params.BeaconConfig().SlotsPerEpoch + 1,
-				finalized:     &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'a'}, 32)},
-				justified:     &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'b'}, 32)},
-				bestJustified: &ethpb.Checkpoint{Epoch: 3, Root: bytesutil.PadTo([]byte{'c'}, 32)},
-				shouldEqual:   false,
-			},
-		},
-		{
-			name: "Justified higher than best justified. No change",
-			args: args{
-				slot:          params.BeaconConfig().SlotsPerEpoch,
-				finalized:     &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'a'}, 32)},
-				justified:     &ethpb.Checkpoint{Epoch: 3, Root: bytesutil.PadTo([]byte{'b'}, 32)},
-				bestJustified: &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'c'}, 32)},
-				shouldEqual:   false,
-			},
-		},
-		{
-			name: "Best justified not on the same chain as finalized. No change",
-			args: args{
-				slot:          params.BeaconConfig().SlotsPerEpoch,
-				finalized:     &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'a'}, 32)},
-				justified:     &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'b'}, 32)},
-				bestJustified: &ethpb.Checkpoint{Epoch: 3, Root: bytesutil.PadTo([]byte{'d'}, 32)},
-				shouldEqual:   false,
-			},
-		},
-		{
-			name: "Best justified on the same chain as finalized. Yes change",
-			args: args{
-				slot:          params.BeaconConfig().SlotsPerEpoch,
-				finalized:     &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'a'}, 32)},
-				justified:     &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'b'}, 32)},
-				bestJustified: &ethpb.Checkpoint{Epoch: 3, Root: bytesutil.PadTo([]byte{'c'}, 32)},
-				shouldEqual:   true,
-			},
-		},
-	}
-	for _, test := range tests {
-		service, err := NewService(ctx, opts...)
-		require.NoError(t, err)
-		s := store.New(test.args.justified, test.args.finalized)
-		s.SetBestJustifiedCheckpt(test.args.bestJustified)
-		service.store = s
-
-		require.NoError(t, service.NewSlot(ctx, test.args.slot))
-		if test.args.shouldEqual {
-			require.DeepSSZEqual(t, service.store.BestJustifiedCheckpt(), service.store.JustifiedCheckpt())
-		} else {
-			require.DeepNotSSZEqual(t, service.store.BestJustifiedCheckpt(), service.store.JustifiedCheckpt())
-		}
-	}
-}
--- a/beacon-chain/blockchain/optimistic_sync.go
+++ b/beacon-chain/blockchain/optimistic_sync.go
@@ -1,170 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	enginev1 "github.com/prysmaticlabs/prysm/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/sirupsen/logrus"
-	"go.opencensus.io/trace"
-)
-
-// notifyForkchoiceUpdate signals execution engine the fork choice updates. Execution engine should:
-// 1. Re-organizes the execution payload chain and corresponding state to make head_block_hash the head.
-// 2. Applies finality to the execution state: it irreversibly persists the chain of all execution payloads and corresponding state, up to and including finalized_block_hash.
-func (s *Service) notifyForkchoiceUpdate(ctx context.Context, headBlk block.BeaconBlock, headRoot [32]byte, finalizedRoot [32]byte) (*enginev1.PayloadIDBytes, error) {
-	ctx, span := trace.StartSpan(ctx, "blockChain.notifyForkchoiceUpdate")
-	defer span.End()
-
-	if headBlk == nil || headBlk.IsNil() || headBlk.Body().IsNil() {
-		return nil, errors.New("nil head block")
-	}
-	// Must not call fork choice updated until the transition conditions are met on the Pow network.
-	isExecutionBlk, err := blocks.IsExecutionBlock(headBlk.Body())
-	if err != nil {
-		return nil, errors.Wrap(err, "could not determine if block is execution block")
-	}
-	if !isExecutionBlk {
-		return nil, nil
-	}
-	headPayload, err := headBlk.Body().ExecutionPayload()
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get execution payload")
-	}
-	finalizedBlock, err := s.cfg.BeaconDB.Block(ctx, s.ensureRootNotZeros(finalizedRoot))
-	if err != nil {
-		return nil, errors.Wrap(err, "could not get finalized block")
-	}
-	var finalizedHash []byte
-	if blocks.IsPreBellatrixVersion(finalizedBlock.Block().Version()) {
-		finalizedHash = params.BeaconConfig().ZeroHash[:]
-	} else {
-		payload, err := finalizedBlock.Block().Body().ExecutionPayload()
-		if err != nil {
-			return nil, errors.Wrap(err, "could not get finalized block execution payload")
-		}
-		finalizedHash = payload.BlockHash
-	}
-
-	fcs := &enginev1.ForkchoiceState{
-		HeadBlockHash:      headPayload.BlockHash,
-		SafeBlockHash:      headPayload.BlockHash,
-		FinalizedBlockHash: finalizedHash,
-	}
-
-	// payload attribute is only required when requesting payload, here we are just updating fork choice, so it is nil.
-	payloadID, _, err := s.cfg.ExecutionEngineCaller.ForkchoiceUpdated(ctx, fcs, nil /*payload attribute*/)
-	if err != nil {
-		switch err {
-		case powchain.ErrAcceptedSyncingPayloadStatus:
-			log.WithFields(logrus.Fields{
-				"headSlot":      headBlk.Slot(),
-				"headHash":      fmt.Sprintf("%#x", bytesutil.Trunc(headPayload.BlockHash)),
-				"finalizedHash": fmt.Sprintf("%#x", bytesutil.Trunc(finalizedHash)),
-			}).Info("Called fork choice updated with optimistic block")
-			return payloadID, nil
-		default:
-			return nil, errors.Wrap(err, "could not notify forkchoice update from execution engine")
-		}
-	}
-	if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, headRoot); err != nil {
-		return nil, errors.Wrap(err, "could not set block to valid")
-	}
-	return payloadID, nil
-}
-
-// notifyForkchoiceUpdate signals execution engine on a new payload.
-// It returns true if the EL has returned VALID for the block
-func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion, postStateVersion int,
-	preStateHeader, postStateHeader *ethpb.ExecutionPayloadHeader, blk block.SignedBeaconBlock) (bool, error) {
-	ctx, span := trace.StartSpan(ctx, "blockChain.notifyNewPayload")
-	defer span.End()
-
-	// Execution payload is only supported in Bellatrix and beyond. Pre
-	// merge blocks are never optimistic
-	if blocks.IsPreBellatrixVersion(postStateVersion) {
-		return true, nil
-	}
-	if err := helpers.BeaconBlockIsNil(blk); err != nil {
-		return false, err
-	}
-	body := blk.Block().Body()
-	enabled, err := blocks.IsExecutionEnabledUsingHeader(postStateHeader, body)
-	if err != nil {
-		return false, errors.Wrap(err, "could not determine if execution is enabled")
-	}
-	if !enabled {
-		return true, nil
-	}
-	payload, err := body.ExecutionPayload()
-	if err != nil {
-		return false, errors.Wrap(err, "could not get execution payload")
-	}
-	_, err = s.cfg.ExecutionEngineCaller.NewPayload(ctx, payload)
-	if err != nil {
-		switch err {
-		case powchain.ErrAcceptedSyncingPayloadStatus:
-			log.WithFields(logrus.Fields{
-				"slot":      blk.Block().Slot(),
-				"blockHash": fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash)),
-			}).Info("Called new payload with optimistic block")
-			return false, nil
-		default:
-			return false, errors.Wrap(err, "could not validate execution payload from execution engine")
-		}
-	}
-
-	// During the transition event, the transition block should be verified for sanity.
-	if blocks.IsPreBellatrixVersion(preStateVersion) {
-		// Handle case where pre-state is Altair but block contains payload.
-		// To reach here, the block must have contained a valid payload.
-		return true, s.validateMergeBlock(ctx, blk)
-	}
-	atTransition, err := blocks.IsMergeTransitionBlockUsingPreStatePayloadHeader(preStateHeader, body)
-	if err != nil {
-		return true, errors.Wrap(err, "could not check if merge block is terminal")
-	}
-	if !atTransition {
-		return true, nil
-	}
-	return true, s.validateMergeBlock(ctx, blk)
-}
-
-// optimisticCandidateBlock returns true if this block can be optimistically synced.
-//
-// Spec pseudocode definition:
-// def is_optimistic_candidate_block(opt_store: OptimisticStore, current_slot: Slot, block: BeaconBlock) -> bool:
-//    if is_execution_block(opt_store.blocks[block.parent_root]):
-//        return True
-//
-//    if block.slot + SAFE_SLOTS_TO_IMPORT_OPTIMISTICALLY <= current_slot:
-//        return True
-//
-//    return False
-func (s *Service) optimisticCandidateBlock(ctx context.Context, blk block.BeaconBlock) (bool, error) {
-	if blk.Slot()+params.BeaconConfig().SafeSlotsToImportOptimistically <= s.CurrentSlot() {
-		return true, nil
-	}
-
-	parent, err := s.cfg.BeaconDB.Block(ctx, bytesutil.ToBytes32(blk.ParentRoot()))
-	if err != nil {
-		return false, err
-	}
-	if parent == nil {
-		return false, errNilParentInDB
-	}
-
-	parentIsExecutionBlock, err := blocks.IsExecutionBlock(parent.Block().Body())
-	if err != nil {
-		return false, err
-	}
-	return parentIsExecutionBlock, nil
-}
--- a/beacon-chain/blockchain/optimistic_sync_test.go
+++ b/beacon-chain/blockchain/optimistic_sync_test.go
@@ -1,673 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"testing"
-	"time"
-
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
-	mockPOW "github.com/prysmaticlabs/prysm/beacon-chain/powchain/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/runtime/version"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	"github.com/prysmaticlabs/prysm/time/slots"
-)
-
-func Test_NotifyForkchoiceUpdate(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	altairBlk, err := wrapper.WrappedSignedBeaconBlock(util.NewBeaconBlockAltair())
-	require.NoError(t, err)
-	altairBlkRoot, err := altairBlk.Block().HashTreeRoot()
-	require.NoError(t, err)
-	bellatrixBlk, err := wrapper.WrappedSignedBeaconBlock(util.NewBeaconBlockBellatrix())
-	require.NoError(t, err)
-	bellatrixBlkRoot, err := bellatrixBlk.Block().HashTreeRoot()
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, altairBlk))
-	require.NoError(t, beaconDB.SaveBlock(ctx, bellatrixBlk))
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 0, [32]byte{}, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-
-	tests := []struct {
-		name             string
-		blk              block.BeaconBlock
-		finalizedRoot    [32]byte
-		newForkchoiceErr error
-		errString        string
-	}{
-		{
-			name:      "nil block",
-			errString: "nil head block",
-		},
-		{
-			name: "phase0 block",
-			blk: func() block.BeaconBlock {
-				b, err := wrapper.WrappedBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}})
-				require.NoError(t, err)
-				return b
-			}(),
-		},
-		{
-			name: "altair block",
-			blk: func() block.BeaconBlock {
-				b, err := wrapper.WrappedBeaconBlock(&ethpb.BeaconBlockAltair{Body: &ethpb.BeaconBlockBodyAltair{}})
-				require.NoError(t, err)
-				return b
-			}(),
-		},
-		{
-			name: "not execution block",
-			blk: func() block.BeaconBlock {
-				b, err := wrapper.WrappedBeaconBlock(&ethpb.BeaconBlockBellatrix{
-					Body: &ethpb.BeaconBlockBodyBellatrix{
-						ExecutionPayload: &v1.ExecutionPayload{
-							ParentHash:    make([]byte, fieldparams.RootLength),
-							FeeRecipient:  make([]byte, fieldparams.FeeRecipientLength),
-							StateRoot:     make([]byte, fieldparams.RootLength),
-							ReceiptsRoot:  make([]byte, fieldparams.RootLength),
-							LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
-							PrevRandao:    make([]byte, fieldparams.RootLength),
-							BaseFeePerGas: make([]byte, fieldparams.RootLength),
-							BlockHash:     make([]byte, fieldparams.RootLength),
-						},
-					},
-				})
-				require.NoError(t, err)
-				return b
-			}(),
-		},
-		{
-			name: "happy case: finalized root is altair block",
-			blk: func() block.BeaconBlock {
-				b, err := wrapper.WrappedBeaconBlock(&ethpb.BeaconBlockBellatrix{
-					Body: &ethpb.BeaconBlockBodyBellatrix{
-						ExecutionPayload: &v1.ExecutionPayload{},
-					},
-				})
-				require.NoError(t, err)
-				return b
-			}(),
-			finalizedRoot: altairBlkRoot,
-		},
-		{
-			name: "happy case: finalized root is bellatrix block",
-			blk: func() block.BeaconBlock {
-				b, err := wrapper.WrappedBeaconBlock(&ethpb.BeaconBlockBellatrix{
-					Body: &ethpb.BeaconBlockBodyBellatrix{
-						ExecutionPayload: &v1.ExecutionPayload{},
-					},
-				})
-				require.NoError(t, err)
-				return b
-			}(),
-			finalizedRoot: bellatrixBlkRoot,
-		},
-		{
-			name: "forkchoice updated with optimistic block",
-			blk: func() block.BeaconBlock {
-				b, err := wrapper.WrappedBeaconBlock(&ethpb.BeaconBlockBellatrix{
-					Body: &ethpb.BeaconBlockBodyBellatrix{
-						ExecutionPayload: &v1.ExecutionPayload{},
-					},
-				})
-				require.NoError(t, err)
-				return b
-			}(),
-			newForkchoiceErr: powchain.ErrAcceptedSyncingPayloadStatus,
-			finalizedRoot:    bellatrixBlkRoot,
-		},
-		{
-			name: "forkchoice updated with invalid block",
-			blk: func() block.BeaconBlock {
-				b, err := wrapper.WrappedBeaconBlock(&ethpb.BeaconBlockBellatrix{
-					Body: &ethpb.BeaconBlockBodyBellatrix{
-						ExecutionPayload: &v1.ExecutionPayload{},
-					},
-				})
-				require.NoError(t, err)
-				return b
-			}(),
-			newForkchoiceErr: powchain.ErrInvalidPayloadStatus,
-			finalizedRoot:    bellatrixBlkRoot,
-			errString:        "could not notify forkchoice update from execution engine: payload status is INVALID",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			service.cfg.ExecutionEngineCaller = &mockPOW.EngineClient{ErrForkchoiceUpdated: tt.newForkchoiceErr}
-			_, err := service.notifyForkchoiceUpdate(ctx, tt.blk, service.headRoot(), tt.finalizedRoot)
-			if tt.errString != "" {
-				require.ErrorContains(t, tt.errString, err)
-			} else {
-				require.NoError(t, err)
-			}
-		})
-	}
-}
-
-func Test_NotifyNewPayload(t *testing.T) {
-	cfg := params.BeaconConfig()
-	cfg.TerminalTotalDifficulty = "2"
-	params.OverrideBeaconConfig(cfg)
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	phase0State, _ := util.DeterministicGenesisState(t, 1)
-	altairState, _ := util.DeterministicGenesisStateAltair(t, 1)
-	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
-	blk := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &v1.ExecutionPayload{},
-			},
-		},
-	}
-	a := &ethpb.SignedBeaconBlockAltair{
-		Block: &ethpb.BeaconBlockAltair{
-			Body: &ethpb.BeaconBlockBodyAltair{},
-		},
-	}
-	altairBlk, err := wrapper.WrappedSignedBeaconBlock(a)
-	require.NoError(t, err)
-	bellatrixBlk, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	tests := []struct {
-		name           string
-		preState       state.BeaconState
-		postState      state.BeaconState
-		isValidPayload bool
-		blk            block.SignedBeaconBlock
-		newPayloadErr  error
-		errString      string
-	}{
-		{
-			name:           "phase 0 post state",
-			postState:      phase0State,
-			preState:       phase0State,
-			isValidPayload: true,
-		},
-		{
-			name:           "altair post state",
-			postState:      altairState,
-			preState:       altairState,
-			isValidPayload: true,
-		},
-		{
-			name:           "nil beacon block",
-			postState:      bellatrixState,
-			preState:       bellatrixState,
-			errString:      "signed beacon block can't be nil",
-			isValidPayload: false,
-		},
-		{
-			name:           "new payload with optimistic block",
-			postState:      bellatrixState,
-			preState:       bellatrixState,
-			blk:            bellatrixBlk,
-			newPayloadErr:  powchain.ErrAcceptedSyncingPayloadStatus,
-			isValidPayload: false,
-		},
-		{
-			name:           "new payload with invalid block",
-			postState:      bellatrixState,
-			preState:       bellatrixState,
-			blk:            bellatrixBlk,
-			newPayloadErr:  powchain.ErrInvalidPayloadStatus,
-			errString:      "could not validate execution payload from execution engine: payload status is INVALID",
-			isValidPayload: false,
-		},
-		{
-			name:           "altair pre state, altair block",
-			postState:      bellatrixState,
-			preState:       altairState,
-			blk:            altairBlk,
-			isValidPayload: true,
-		},
-		{
-			name:      "altair pre state, happy case",
-			postState: bellatrixState,
-			preState:  altairState,
-			blk: func() block.SignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
-				b, err := wrapper.WrappedSignedBeaconBlock(blk)
-				require.NoError(t, err)
-				return b
-			}(),
-			isValidPayload: true,
-		},
-		{
-			name:           "could not get merge block",
-			postState:      bellatrixState,
-			preState:       bellatrixState,
-			blk:            bellatrixBlk,
-			errString:      "could not get merge block parent hash and total difficulty",
-			isValidPayload: false,
-		},
-		{
-			name:      "not at merge transition",
-			postState: bellatrixState,
-			preState:  bellatrixState,
-			blk: func() block.SignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash:    make([]byte, fieldparams.RootLength),
-								FeeRecipient:  make([]byte, fieldparams.FeeRecipientLength),
-								StateRoot:     make([]byte, fieldparams.RootLength),
-								ReceiptsRoot:  make([]byte, fieldparams.RootLength),
-								LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
-								PrevRandao:    make([]byte, fieldparams.RootLength),
-								BaseFeePerGas: make([]byte, fieldparams.RootLength),
-								BlockHash:     make([]byte, fieldparams.RootLength),
-							},
-						},
-					},
-				}
-				b, err := wrapper.WrappedSignedBeaconBlock(blk)
-				require.NoError(t, err)
-				return b
-			}(),
-			isValidPayload: true,
-		},
-		{
-			name:           "could not get merge block",
-			postState:      bellatrixState,
-			preState:       bellatrixState,
-			blk:            bellatrixBlk,
-			errString:      "could not get merge block parent hash and total difficulty",
-			isValidPayload: false,
-		},
-		{
-			name:      "happy case",
-			postState: bellatrixState,
-			preState:  bellatrixState,
-			blk: func() block.SignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
-				b, err := wrapper.WrappedSignedBeaconBlock(blk)
-				require.NoError(t, err)
-				return b
-			}(),
-			isValidPayload: true,
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			e := &mockPOW.EngineClient{ErrNewPayload: tt.newPayloadErr, BlockByHashMap: map[[32]byte]*v1.ExecutionBlock{}}
-			e.BlockByHashMap[[32]byte{'a'}] = &v1.ExecutionBlock{
-				ParentHash:      bytesutil.PadTo([]byte{'b'}, fieldparams.RootLength),
-				TotalDifficulty: "0x2",
-			}
-			e.BlockByHashMap[[32]byte{'b'}] = &v1.ExecutionBlock{
-				ParentHash:      bytesutil.PadTo([]byte{'3'}, fieldparams.RootLength),
-				TotalDifficulty: "0x1",
-			}
-			service.cfg.ExecutionEngineCaller = e
-			var payload *ethpb.ExecutionPayloadHeader
-			if tt.preState.Version() == version.Bellatrix {
-				payload, err = tt.preState.LatestExecutionPayloadHeader()
-				require.NoError(t, err)
-			}
-			root := [32]byte{'a'}
-			require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 0, root, root, params.BeaconConfig().ZeroHash, 0, 0))
-			postVersion, postHeader, err := getStateVersionAndPayload(tt.postState)
-			require.NoError(t, err)
-			isValidPayload, err := service.notifyNewPayload(ctx, tt.preState.Version(), postVersion, payload, postHeader, tt.blk)
-			if tt.errString != "" {
-				require.ErrorContains(t, tt.errString, err)
-			} else {
-				require.NoError(t, err)
-				require.Equal(t, tt.isValidPayload, isValidPayload)
-			}
-		})
-	}
-}
-
-func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
-	cfg := params.BeaconConfig()
-	cfg.TerminalTotalDifficulty = "2"
-	params.OverrideBeaconConfig(cfg)
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
-	blk := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &v1.ExecutionPayload{
-					ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-				},
-			},
-		},
-	}
-	bellatrixBlk, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	e := &mockPOW.EngineClient{BlockByHashMap: map[[32]byte]*v1.ExecutionBlock{}}
-	e.BlockByHashMap[[32]byte{'a'}] = &v1.ExecutionBlock{
-		ParentHash:      bytesutil.PadTo([]byte{'b'}, fieldparams.RootLength),
-		TotalDifficulty: "0x2",
-	}
-	e.BlockByHashMap[[32]byte{'b'}] = &v1.ExecutionBlock{
-		ParentHash:      bytesutil.PadTo([]byte{'3'}, fieldparams.RootLength),
-		TotalDifficulty: "0x1",
-	}
-	service.cfg.ExecutionEngineCaller = e
-	payload, err := bellatrixState.LatestExecutionPayloadHeader()
-	require.NoError(t, err)
-	postVersion, postHeader, err := getStateVersionAndPayload(bellatrixState)
-	require.NoError(t, err)
-	validated, err := service.notifyNewPayload(ctx, bellatrixState.Version(), postVersion, payload, postHeader, bellatrixBlk)
-	require.NoError(t, err)
-	require.Equal(t, true, validated)
-}
-
-func Test_IsOptimisticCandidateBlock(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-	params.OverrideBeaconConfig(params.MainnetConfig())
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	params.BeaconConfig().SafeSlotsToImportOptimistically = 128
-	service.genesisTime = time.Now().Add(-time.Second * 12 * 2 * 128)
-
-	parentBlk := util.NewBeaconBlockBellatrix()
-	wrappedParentBlock, err := wrapper.WrappedSignedBeaconBlock(parentBlk)
-	require.NoError(t, err)
-	parentRoot, err := wrappedParentBlock.Block().HashTreeRoot()
-	require.NoError(t, err)
-
-	tests := []struct {
-		name      string
-		blk       block.BeaconBlock
-		justified block.SignedBeaconBlock
-		want      bool
-	}{
-		{
-			name: "deep block",
-			blk: func(tt *testing.T) block.BeaconBlock {
-				blk := util.NewBeaconBlockBellatrix()
-				blk.Block.Slot = 1
-				blk.Block.ParentRoot = parentRoot[:]
-				wr, err := wrapper.WrappedBeaconBlock(blk.Block)
-				require.NoError(tt, err)
-				return wr
-			}(t),
-			justified: func(tt *testing.T) block.SignedBeaconBlock {
-				blk := util.NewBeaconBlockBellatrix()
-				blk.Block.Slot = 32
-				blk.Block.ParentRoot = parentRoot[:]
-				wr, err := wrapper.WrappedSignedBeaconBlock(blk)
-				require.NoError(tt, err)
-				return wr
-			}(t),
-			want: true,
-		},
-		{
-			name: "shallow block, Altair justified chkpt",
-			blk: func(tt *testing.T) block.BeaconBlock {
-				blk := util.NewBeaconBlockAltair()
-				blk.Block.Slot = 200
-				blk.Block.ParentRoot = parentRoot[:]
-				wr, err := wrapper.WrappedBeaconBlock(blk.Block)
-				require.NoError(tt, err)
-				return wr
-			}(t),
-			justified: func(tt *testing.T) block.SignedBeaconBlock {
-				blk := util.NewBeaconBlockAltair()
-				blk.Block.Slot = 32
-				blk.Block.ParentRoot = parentRoot[:]
-				wr, err := wrapper.WrappedSignedBeaconBlock(blk)
-				require.NoError(tt, err)
-				return wr
-			}(t),
-			want: false,
-		},
-		{
-			name: "shallow block, Bellatrix justified chkpt without execution",
-			blk: func(tt *testing.T) block.BeaconBlock {
-				blk := util.NewBeaconBlockBellatrix()
-				blk.Block.Slot = 200
-				blk.Block.ParentRoot = parentRoot[:]
-				wr, err := wrapper.WrappedBeaconBlock(blk.Block)
-				require.NoError(tt, err)
-				return wr
-			}(t),
-			justified: func(tt *testing.T) block.SignedBeaconBlock {
-				blk := util.NewBeaconBlockBellatrix()
-				blk.Block.Slot = 32
-				blk.Block.ParentRoot = parentRoot[:]
-				wr, err := wrapper.WrappedSignedBeaconBlock(blk)
-				require.NoError(tt, err)
-				return wr
-			}(t),
-			want: false,
-		},
-	}
-	for _, tt := range tests {
-		jRoot, err := tt.justified.Block().HashTreeRoot()
-		require.NoError(t, err)
-		require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, tt.justified))
-		service.store.SetJustifiedCheckpt(
-			&ethpb.Checkpoint{
-				Root:  jRoot[:],
-				Epoch: slots.ToEpoch(tt.justified.Block().Slot()),
-			})
-		require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrappedParentBlock))
-
-		candidate, err := service.optimisticCandidateBlock(ctx, tt.blk)
-		require.NoError(t, err)
-		require.Equal(t, tt.want, candidate, tt.name)
-	}
-}
-
-func Test_IsOptimisticShallowExecutionParent(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-	params.OverrideBeaconConfig(params.MainnetConfig())
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-	}
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	params.BeaconConfig().SafeSlotsToImportOptimistically = 128
-	service.genesisTime = time.Now().Add(-time.Second * 12 * 2 * 128)
-	payload := &v1.ExecutionPayload{
-		ParentHash:    make([]byte, 32),
-		FeeRecipient:  make([]byte, 20),
-		StateRoot:     make([]byte, 32),
-		ReceiptsRoot:  make([]byte, 32),
-		LogsBloom:     make([]byte, 256),
-		PrevRandao:    make([]byte, 32),
-		BaseFeePerGas: bytesutil.PadTo([]byte{1, 2, 3, 4}, fieldparams.RootLength),
-		BlockHash:     make([]byte, 32),
-		BlockNumber:   100,
-	}
-	body := &ethpb.BeaconBlockBodyBellatrix{ExecutionPayload: payload}
-	b := &ethpb.BeaconBlockBellatrix{Body: body, Slot: 200}
-	rawSigned := &ethpb.SignedBeaconBlockBellatrix{Block: b}
-	blk := util.HydrateSignedBeaconBlockBellatrix(rawSigned)
-	wr, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wr))
-	blkRoot, err := wr.Block().HashTreeRoot()
-	require.NoError(t, err)
-
-	childBlock := util.NewBeaconBlockBellatrix()
-	childBlock.Block.ParentRoot = blkRoot[:]
-	// shallow block
-	childBlock.Block.Slot = 201
-	wrappedChild, err := wrapper.WrappedSignedBeaconBlock(childBlock)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrappedChild))
-	candidate, err := service.optimisticCandidateBlock(ctx, wrappedChild.Block())
-	require.NoError(t, err)
-	require.Equal(t, true, candidate)
-}
-
-func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-	params.OverrideBeaconConfig(params.MainnetConfig())
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	stateGen := stategen.New(beaconDB)
-	fcs := protoarray.New(0, 0, [32]byte{})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stateGen),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	genesisStateRoot := [32]byte{}
-	genesisBlk := blocks.NewGenesisBlock(genesisStateRoot[:])
-	wr, err := wrapper.WrappedSignedBeaconBlock(genesisBlk)
-	require.NoError(t, err)
-	assert.NoError(t, beaconDB.SaveBlock(ctx, wr))
-	genesisRoot, err := genesisBlk.Block.HashTreeRoot()
-	require.NoError(t, err)
-	assert.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 0, genesisRoot, params.BeaconConfig().ZeroHash,
-		params.BeaconConfig().ZeroHash, 0, 0))
-	genesisSummary := &ethpb.StateSummary{
-		Root: genesisStateRoot[:],
-		Slot: 0,
-	}
-	require.NoError(t, beaconDB.SaveStateSummary(ctx, genesisSummary))
-
-	// Get last validated checkpoint
-	origCheckpoint, err := service.cfg.BeaconDB.LastValidatedCheckpoint(ctx)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveLastValidatedCheckpoint(ctx, origCheckpoint))
-
-	// Optimistic finalized checkpoint
-	blk := util.NewBeaconBlock()
-	blk.Block.Slot = 320
-	blk.Block.ParentRoot = genesisRoot[:]
-	wr, err = wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wr))
-	opRoot, err := blk.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	opCheckpoint := &ethpb.Checkpoint{
-		Root:  opRoot[:],
-		Epoch: 10,
-	}
-	opStateSummary := &ethpb.StateSummary{
-		Root: opRoot[:],
-		Slot: 320,
-	}
-	require.NoError(t, beaconDB.SaveStateSummary(ctx, opStateSummary))
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 320, opRoot, genesisRoot,
-		params.BeaconConfig().ZeroHash, 10, 10))
-	assert.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, opRoot))
-	require.NoError(t, service.updateFinalized(ctx, opCheckpoint))
-	cp, err := service.cfg.BeaconDB.LastValidatedCheckpoint(ctx)
-	require.NoError(t, err)
-	require.DeepEqual(t, origCheckpoint.Root, cp.Root)
-	require.Equal(t, origCheckpoint.Epoch, cp.Epoch)
-
-	// Validated finalized checkpoint
-	blk = util.NewBeaconBlock()
-	blk.Block.Slot = 640
-	blk.Block.ParentRoot = opRoot[:]
-	wr, err = wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wr))
-	validRoot, err := blk.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	validCheckpoint := &ethpb.Checkpoint{
-		Root:  validRoot[:],
-		Epoch: 20,
-	}
-	validSummary := &ethpb.StateSummary{
-		Root: validRoot[:],
-		Slot: 640,
-	}
-	require.NoError(t, beaconDB.SaveStateSummary(ctx, validSummary))
-	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 640, validRoot, params.BeaconConfig().ZeroHash,
-		params.BeaconConfig().ZeroHash, 20, 20))
-	require.NoError(t, fcs.SetOptimisticToValid(ctx, validRoot))
-	assert.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, validRoot))
-	require.NoError(t, service.updateFinalized(ctx, validCheckpoint))
-	cp, err = service.cfg.BeaconDB.LastValidatedCheckpoint(ctx)
-	require.NoError(t, err)
-
-	optimistic, err := service.IsOptimisticForRoot(ctx, validRoot)
-	require.NoError(t, err)
-	require.Equal(t, false, optimistic)
-	require.DeepEqual(t, validCheckpoint.Root, cp.Root)
-	require.Equal(t, validCheckpoint.Epoch, cp.Epoch)
-}
--- a/beacon-chain/blockchain/options.go
+++ b/beacon-chain/blockchain/options.go
@@ -1,154 +0,0 @@
-package blockchain
-
-import (
-	"github.com/prysmaticlabs/prysm/async/event"
-	"github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache"
-	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/db"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
-	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
-	"github.com/prysmaticlabs/prysm/beacon-chain/operations/slashings"
-	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
-	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
-	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-)
-
-type Option func(s *Service) error
-
-// WithMaxGoroutines to control resource use of the blockchain service.
-func WithMaxGoroutines(x int) Option {
-	return func(s *Service) error {
-		s.cfg.MaxRoutines = x
-		return nil
-	}
-}
-
-// WithWeakSubjectivityCheckpoint for checkpoint sync.
-func WithWeakSubjectivityCheckpoint(c *ethpb.Checkpoint) Option {
-	return func(s *Service) error {
-		s.cfg.WeakSubjectivityCheckpt = c
-		return nil
-	}
-}
-
-// WithDatabase for head access.
-func WithDatabase(beaconDB db.HeadAccessDatabase) Option {
-	return func(s *Service) error {
-		s.cfg.BeaconDB = beaconDB
-		return nil
-	}
-}
-
-// WithChainStartFetcher to retrieve information about genesis.
-func WithChainStartFetcher(f powchain.ChainStartFetcher) Option {
-	return func(s *Service) error {
-		s.cfg.ChainStartFetcher = f
-		return nil
-	}
-}
-
-// WithExecutionEngineCaller to call execution engine.
-func WithExecutionEngineCaller(c powchain.EngineCaller) Option {
-	return func(s *Service) error {
-		s.cfg.ExecutionEngineCaller = c
-		return nil
-	}
-}
-
-// WithDepositCache for deposit lifecycle after chain inclusion.
-func WithDepositCache(c *depositcache.DepositCache) Option {
-	return func(s *Service) error {
-		s.cfg.DepositCache = c
-		return nil
-	}
-}
-
-// WithAttestationPool for attestation lifecycle after chain inclusion.
-func WithAttestationPool(p attestations.Pool) Option {
-	return func(s *Service) error {
-		s.cfg.AttPool = p
-		return nil
-	}
-}
-
-// WithExitPool for exits lifecycle after chain inclusion.
-func WithExitPool(p voluntaryexits.PoolManager) Option {
-	return func(s *Service) error {
-		s.cfg.ExitPool = p
-		return nil
-	}
-}
-
-// WithSlashingPool for slashings lifecycle after chain inclusion.
-func WithSlashingPool(p slashings.PoolManager) Option {
-	return func(s *Service) error {
-		s.cfg.SlashingPool = p
-		return nil
-	}
-}
-
-// WithP2PBroadcaster to broadcast messages after appropriate processing.
-func WithP2PBroadcaster(p p2p.Broadcaster) Option {
-	return func(s *Service) error {
-		s.cfg.P2p = p
-		return nil
-	}
-}
-
-// WithStateNotifier to notify an event feed of state processing.
-func WithStateNotifier(n statefeed.Notifier) Option {
-	return func(s *Service) error {
-		s.cfg.StateNotifier = n
-		return nil
-	}
-}
-
-// WithForkChoiceStore to update an optimized fork-choice representation.
-func WithForkChoiceStore(f forkchoice.ForkChoicer) Option {
-	return func(s *Service) error {
-		s.cfg.ForkChoiceStore = f
-		return nil
-	}
-}
-
-// WithAttestationService for dealing with attestation lifecycles.
-func WithAttestationService(srv *attestations.Service) Option {
-	return func(s *Service) error {
-		s.cfg.AttService = srv
-		return nil
-	}
-}
-
-// WithStateGen for managing state regeneration and replay.
-func WithStateGen(g *stategen.State) Option {
-	return func(s *Service) error {
-		s.cfg.StateGen = g
-		return nil
-	}
-}
-
-// WithSlasherAttestationsFeed to forward attestations into slasher if enabled.
-func WithSlasherAttestationsFeed(f *event.Feed) Option {
-	return func(s *Service) error {
-		s.cfg.SlasherAttestationsFeed = f
-		return nil
-	}
-}
-
-func withStateBalanceCache(c *stateBalanceCache) Option {
-	return func(s *Service) error {
-		s.justifiedBalances = c
-		return nil
-	}
-}
-
-// WithFinalizedStateAtStartUp to store finalized state at start up.
-func WithFinalizedStateAtStartUp(st state.BeaconState) Option {
-	return func(s *Service) error {
-		s.cfg.FinalizedStateAtStartUp = st
-		return nil
-	}
-}
--- a/beacon-chain/blockchain/pow_block.go
+++ b/beacon-chain/blockchain/pow_block.go
@@ -1,141 +0,0 @@
-package blockchain
-
-import (
-	"bytes"
-	"context"
-	"fmt"
-	"math/big"
-
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/holiman/uint256"
-	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	enginev1 "github.com/prysmaticlabs/prysm/proto/engine/v1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/time/slots"
-	"github.com/sirupsen/logrus"
-)
-
-// validateMergeBlock validates terminal block hash in the event of manual overrides before checking for total difficulty.
-//
-// def validate_merge_block(block: BeaconBlock) -> None:
-//    if TERMINAL_BLOCK_HASH != Hash32():
-//        # If `TERMINAL_BLOCK_HASH` is used as an override, the activation epoch must be reached.
-//        assert compute_epoch_at_slot(block.slot) >= TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
-//        assert block.body.execution_payload.parent_hash == TERMINAL_BLOCK_HASH
-//        return
-//
-//    pow_block = get_pow_block(block.body.execution_payload.parent_hash)
-//    # Check if `pow_block` is available
-//    assert pow_block is not None
-//    pow_parent = get_pow_block(pow_block.parent_hash)
-//    # Check if `pow_parent` is available
-//    assert pow_parent is not None
-//    # Check if `pow_block` is a valid terminal PoW block
-//    assert is_valid_terminal_pow_block(pow_block, pow_parent)
-func (s *Service) validateMergeBlock(ctx context.Context, b block.SignedBeaconBlock) error {
-	if err := helpers.BeaconBlockIsNil(b); err != nil {
-		return err
-	}
-	payload, err := b.Block().Body().ExecutionPayload()
-	if err != nil {
-		return err
-	}
-	if payload == nil {
-		return errors.New("nil execution payload")
-	}
-	if err := validateTerminalBlockHash(b.Block().Slot(), payload); err != nil {
-		return errors.Wrap(err, "could not validate terminal block hash")
-	}
-	mergeBlockParentHash, mergeBlockTD, err := s.getBlkParentHashAndTD(ctx, payload.ParentHash)
-	if err != nil {
-		return errors.Wrap(err, "could not get merge block parent hash and total difficulty")
-	}
-	_, mergeBlockParentTD, err := s.getBlkParentHashAndTD(ctx, mergeBlockParentHash)
-	if err != nil {
-		return errors.Wrap(err, "could not get merge parent block total difficulty")
-	}
-	valid, err := validateTerminalBlockDifficulties(mergeBlockTD, mergeBlockParentTD)
-	if err != nil {
-		return err
-	}
-	if !valid {
-		return fmt.Errorf("invalid TTD, configTTD: %s, currentTTD: %s, parentTTD: %s",
-			params.BeaconConfig().TerminalTotalDifficulty, mergeBlockTD, mergeBlockParentTD)
-	}
-
-	log.WithFields(logrus.Fields{
-		"slot":                            b.Block().Slot(),
-		"mergeBlockHash":                  common.BytesToHash(payload.ParentHash).String(),
-		"mergeBlockParentHash":            common.BytesToHash(mergeBlockParentHash).String(),
-		"terminalTotalDifficulty":         params.BeaconConfig().TerminalTotalDifficulty,
-		"mergeBlockTotalDifficulty":       mergeBlockTD,
-		"mergeBlockParentTotalDifficulty": mergeBlockParentTD,
-	}).Info("Validated terminal block")
-
-	return nil
-}
-
-// getBlkParentHashAndTD retrieves the parent hash and total difficulty of the given block.
-func (s *Service) getBlkParentHashAndTD(ctx context.Context, blkHash []byte) ([]byte, *uint256.Int, error) {
-	blk, err := s.cfg.ExecutionEngineCaller.ExecutionBlockByHash(ctx, common.BytesToHash(blkHash))
-	if err != nil {
-		return nil, nil, errors.Wrap(err, "could not get pow block")
-	}
-	if blk == nil {
-		return nil, nil, errors.New("pow block is nil")
-	}
-	blkTDBig, err := hexutil.DecodeBig(blk.TotalDifficulty)
-	if err != nil {
-		return nil, nil, errors.Wrap(err, "could not decode merge block total difficulty")
-	}
-	blkTDUint256, overflows := uint256.FromBig(blkTDBig)
-	if overflows {
-		return nil, nil, errors.New("total difficulty overflows")
-	}
-	return blk.ParentHash, blkTDUint256, nil
-}
-
-// validateTerminalBlockHash validates if the merge block is a valid terminal PoW block.
-// spec code:
-// if TERMINAL_BLOCK_HASH != Hash32():
-//        # If `TERMINAL_BLOCK_HASH` is used as an override, the activation epoch must be reached.
-//        assert compute_epoch_at_slot(block.slot) >= TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
-//        assert block.body.execution_payload.parent_hash == TERMINAL_BLOCK_HASH
-//        return
-func validateTerminalBlockHash(blkSlot types.Slot, payload *enginev1.ExecutionPayload) error {
-	if bytesutil.ToBytes32(params.BeaconConfig().TerminalBlockHash.Bytes()) == [32]byte{} {
-		return nil
-	}
-	if params.BeaconConfig().TerminalBlockHashActivationEpoch > slots.ToEpoch(blkSlot) {
-		return errors.New("terminal block hash activation epoch not reached")
-	}
-	if !bytes.Equal(payload.ParentHash, params.BeaconConfig().TerminalBlockHash.Bytes()) {
-		return errors.New("parent hash does not match terminal block hash")
-	}
-	return nil
-}
-
-// validateTerminalBlockDifficulties validates terminal pow block by comparing own total difficulty with parent's total difficulty.
-//
-// def is_valid_terminal_pow_block(block: PowBlock, parent: PowBlock) -> bool:
-//    is_total_difficulty_reached = block.total_difficulty >= TERMINAL_TOTAL_DIFFICULTY
-//    is_parent_total_difficulty_valid = parent.total_difficulty < TERMINAL_TOTAL_DIFFICULTY
-//    return is_total_difficulty_reached and is_parent_total_difficulty_valid
-func validateTerminalBlockDifficulties(currentDifficulty *uint256.Int, parentDifficulty *uint256.Int) (bool, error) {
-	b, ok := new(big.Int).SetString(params.BeaconConfig().TerminalTotalDifficulty, 10)
-	if !ok {
-		return false, errors.New("failed to parse terminal total difficulty")
-	}
-	ttd, of := uint256.FromBig(b)
-	if of {
-		return false, errors.New("overflow terminal total difficulty")
-	}
-	totalDifficultyReached := currentDifficulty.Cmp(ttd) >= 0
-	parentTotalDifficultyValid := ttd.Cmp(parentDifficulty) > 0
-	return totalDifficultyReached && parentTotalDifficultyValid, nil
-}
--- a/beacon-chain/blockchain/pow_block_test.go
+++ b/beacon-chain/blockchain/pow_block_test.go
@@ -1,211 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"fmt"
-	"math/big"
-	"testing"
-
-	"github.com/holiman/uint256"
-	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	mocks "github.com/prysmaticlabs/prysm/beacon-chain/powchain/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	enginev1 "github.com/prysmaticlabs/prysm/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-func Test_validTerminalPowBlock(t *testing.T) {
-	tests := []struct {
-		name              string
-		currentDifficulty *uint256.Int
-		parentDifficulty  *uint256.Int
-		ttd               uint64
-		want              bool
-	}{
-		{
-			name:              "current > ttd, parent > ttd",
-			currentDifficulty: uint256.NewInt(2),
-			parentDifficulty:  uint256.NewInt(2),
-			ttd:               1,
-			want:              false,
-		},
-		{
-			name:              "current < ttd, parent < ttd",
-			currentDifficulty: uint256.NewInt(2),
-			parentDifficulty:  uint256.NewInt(2),
-			ttd:               3,
-			want:              false,
-		},
-		{
-			name:              "current == ttd, parent == ttd",
-			currentDifficulty: uint256.NewInt(2),
-			parentDifficulty:  uint256.NewInt(2),
-			ttd:               2,
-			want:              false,
-		},
-		{
-			name:              "current > ttd, parent == ttd",
-			currentDifficulty: uint256.NewInt(2),
-			parentDifficulty:  uint256.NewInt(1),
-			ttd:               1,
-			want:              false,
-		},
-		{
-			name:              "current == ttd, parent < ttd",
-			currentDifficulty: uint256.NewInt(2),
-			parentDifficulty:  uint256.NewInt(1),
-			ttd:               2,
-			want:              true,
-		},
-		{
-			name:              "current > ttd, parent < ttd",
-			currentDifficulty: uint256.NewInt(3),
-			parentDifficulty:  uint256.NewInt(1),
-			ttd:               2,
-			want:              true,
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			cfg := params.BeaconConfig()
-			cfg.TerminalTotalDifficulty = fmt.Sprint(tt.ttd)
-			params.OverrideBeaconConfig(cfg)
-			got, err := validateTerminalBlockDifficulties(tt.currentDifficulty, tt.parentDifficulty)
-			require.NoError(t, err)
-			if got != tt.want {
-				t.Errorf("validateTerminalBlockDifficulties() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}
-
-func Test_validTerminalPowBlockSpecConfig(t *testing.T) {
-	cfg := params.BeaconConfig()
-	cfg.TerminalTotalDifficulty = "115792089237316195423570985008687907853269984665640564039457584007913129638912"
-	params.OverrideBeaconConfig(cfg)
-
-	i, _ := new(big.Int).SetString("115792089237316195423570985008687907853269984665640564039457584007913129638912", 10)
-	current, of := uint256.FromBig(i)
-	require.Equal(t, of, false)
-	i, _ = new(big.Int).SetString("115792089237316195423570985008687907853269984665640564039457584007913129638911", 10)
-	parent, of := uint256.FromBig(i)
-	require.Equal(t, of, false)
-
-	got, err := validateTerminalBlockDifficulties(current, parent)
-	require.NoError(t, err)
-	require.Equal(t, true, got)
-}
-
-func Test_validateMergeBlock(t *testing.T) {
-	cfg := params.BeaconConfig()
-	cfg.TerminalTotalDifficulty = "2"
-	params.OverrideBeaconConfig(cfg)
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	engine := &mocks.EngineClient{BlockByHashMap: map[[32]byte]*enginev1.ExecutionBlock{}}
-	service.cfg.ExecutionEngineCaller = engine
-	engine.BlockByHashMap[[32]byte{'a'}] = &enginev1.ExecutionBlock{
-		ParentHash:      bytesutil.PadTo([]byte{'b'}, fieldparams.RootLength),
-		TotalDifficulty: "0x2",
-	}
-	engine.BlockByHashMap[[32]byte{'b'}] = &enginev1.ExecutionBlock{
-		ParentHash:      bytesutil.PadTo([]byte{'3'}, fieldparams.RootLength),
-		TotalDifficulty: "0x1",
-	}
-	blk := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Slot: 1,
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &enginev1.ExecutionPayload{
-					ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-				},
-			},
-		},
-	}
-	b, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	require.NoError(t, service.validateMergeBlock(ctx, b))
-
-	cfg.TerminalTotalDifficulty = "1"
-	params.OverrideBeaconConfig(cfg)
-	require.ErrorContains(t, "invalid TTD, configTTD: 1, currentTTD: 2, parentTTD: 1", service.validateMergeBlock(ctx, b))
-}
-
-func Test_getBlkParentHashAndTD(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	engine := &mocks.EngineClient{BlockByHashMap: map[[32]byte]*enginev1.ExecutionBlock{}}
-	service.cfg.ExecutionEngineCaller = engine
-	h := [32]byte{'a'}
-	p := [32]byte{'b'}
-	td := "0x1"
-	engine.BlockByHashMap[h] = &enginev1.ExecutionBlock{
-		ParentHash:      p[:],
-		TotalDifficulty: td,
-	}
-	parentHash, totalDifficulty, err := service.getBlkParentHashAndTD(ctx, h[:])
-	require.NoError(t, err)
-	require.Equal(t, p, bytesutil.ToBytes32(parentHash))
-	require.Equal(t, td, totalDifficulty.String())
-
-	_, _, err = service.getBlkParentHashAndTD(ctx, []byte{'c'})
-	require.ErrorContains(t, "could not get pow block: block not found", err)
-
-	engine.BlockByHashMap[h] = nil
-	_, _, err = service.getBlkParentHashAndTD(ctx, h[:])
-	require.ErrorContains(t, "pow block is nil", err)
-
-	engine.BlockByHashMap[h] = &enginev1.ExecutionBlock{
-		ParentHash:      p[:],
-		TotalDifficulty: "1",
-	}
-	_, _, err = service.getBlkParentHashAndTD(ctx, h[:])
-	require.ErrorContains(t, "could not decode merge block total difficulty: hex string without 0x prefix", err)
-
-	engine.BlockByHashMap[h] = &enginev1.ExecutionBlock{
-		ParentHash:      p[:],
-		TotalDifficulty: "0XFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
-	}
-	_, _, err = service.getBlkParentHashAndTD(ctx, h[:])
-	require.ErrorContains(t, "could not decode merge block total difficulty: hex number > 256 bits", err)
-}
-
-func Test_validateTerminalBlockHash(t *testing.T) {
-	require.NoError(t, validateTerminalBlockHash(1, &enginev1.ExecutionPayload{}))
-
-	cfg := params.BeaconConfig()
-	cfg.TerminalBlockHash = [32]byte{0x01}
-	params.OverrideBeaconConfig(cfg)
-	require.ErrorContains(t, "terminal block hash activation epoch not reached", validateTerminalBlockHash(1, &enginev1.ExecutionPayload{}))
-
-	cfg.TerminalBlockHashActivationEpoch = 0
-	params.OverrideBeaconConfig(cfg)
-	require.ErrorContains(t, "parent hash does not match terminal block hash", validateTerminalBlockHash(1, &enginev1.ExecutionPayload{}))
-
-	require.NoError(t, validateTerminalBlockHash(1, &enginev1.ExecutionPayload{ParentHash: cfg.TerminalBlockHash.Bytes()}))
-}
--- a/beacon-chain/blockchain/process_attestation.go
+++ b/beacon-chain/blockchain/process_attestation.go
@@ -2,19 +2,19 @@ package blockchain

 import (
 	"context"
-	"time"

 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/attestation"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/copyutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 	"go.opencensus.io/trace"
 )

-// OnAttestation is called whenever an attestation is received, verifies the attestation is valid and saves
+// onAttestation is called whenever an attestation is received, verifies the attestation is valid and saves
 // it to the DB. As a stateless function, this does not hold nor delay attestation based on the spec descriptions.
 // The delay is handled by the caller in `processAttestations`.
 //
@@ -36,7 +36,7 @@ import (
 //
 //    # Update latest messages for attesting indices
 //    update_latest_messages(store, indexed_attestation.attesting_indices, attestation)
-func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation) error {
+func (s *Service) onAttestation(ctx context.Context, a *ethpb.Attestation) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onAttestation")
 	defer span.End()

@@ -46,7 +46,7 @@ func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation) error
 	if err := helpers.ValidateSlotTargetEpoch(a.Data); err != nil {
 		return err
 	}
-	tgt := ethpb.CopyCheckpoint(a.Data.Target)
+	tgt := copyutil.CopyCheckpoint(a.Data.Target)

 	// Note that target root check is ignored here because it was performed in sync's validation pipeline:
 	// validate_aggregate_proof.go and validate_beacon_attestation.go
@@ -59,10 +59,10 @@ func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation) error
 		return err
 	}

-	genesisTime := uint64(s.genesisTime.Unix())
+	genesisTime := baseState.GenesisTime()

 	// Verify attestation target is from current epoch or previous epoch.
-	if err := verifyAttTargetEpoch(ctx, genesisTime, uint64(time.Now().Unix()), tgt); err != nil {
+	if err := s.verifyAttTargetEpoch(ctx, genesisTime, uint64(timeutils.Now().Unix()), tgt); err != nil {
 		return err
 	}

@@ -75,20 +75,20 @@ func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation) error
 	// validate_aggregate_proof.go and validate_beacon_attestation.go

 	// Verify attestations can only affect the fork choice of subsequent slots.
-	if err := slots.VerifyTime(genesisTime, a.Data.Slot+1, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
+	if err := helpers.VerifySlotTime(genesisTime, a.Data.Slot+1, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
 		return err
 	}

 	// Use the target state to verify attesting indices are valid.
-	committee, err := helpers.BeaconCommitteeFromState(ctx, baseState, a.Data.Slot, a.Data.CommitteeIndex)
+	committee, err := helpers.BeaconCommitteeFromState(baseState, a.Data.Slot, a.Data.CommitteeIndex)
 	if err != nil {
 		return err
 	}
-	indexedAtt, err := attestation.ConvertToIndexed(ctx, a, committee)
+	indexedAtt, err := attestationutil.ConvertToIndexed(ctx, a, committee)
 	if err != nil {
 		return err
 	}
-	if err := attestation.IsValidAttestationIndices(ctx, indexedAtt); err != nil {
+	if err := attestationutil.IsValidAttestationIndices(ctx, indexedAtt); err != nil {
 		return err
 	}

--- a/beacon-chain/blockchain/process_attestation_helpers.go
+++ b/beacon-chain/blockchain/process_attestation_helpers.go
@@ -7,22 +7,22 @@ import (

 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/async"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/mputil"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )

 // getAttPreState retrieves the att pre state by either from the cache or the DB.
-func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (state.BeaconState, error) {
+func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (iface.BeaconState, error) {
 	// Use a multilock to allow scoped holding of a mutex by a checkpoint root + epoch
 	// allowing us to behave smarter in terms of how this function is used concurrently.
 	epochKey := strconv.FormatUint(uint64(c.Epoch), 10 /* base 10 */)
-	lock := async.NewMultilock(string(c.Root) + epochKey)
+	lock := mputil.NewMultilock(string(c.Root) + epochKey)
 	lock.Lock()
 	defer lock.Unlock()
 	cachedState, err := s.checkpointStateCache.StateByCheckpoint(c)
@@ -38,30 +38,47 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (stat
 		return nil, errors.Wrapf(err, "could not get pre state for epoch %d", c.Epoch)
 	}

-	epochStartSlot, err := slots.EpochStart(c.Epoch)
+	epochStartSlot, err := helpers.StartSlot(c.Epoch)
 	if err != nil {
 		return nil, err
 	}
-	baseState, err = transition.ProcessSlotsIfPossible(ctx, baseState, epochStartSlot)
-	if err != nil {
-		return nil, errors.Wrapf(err, "could not process slots up to epoch %d", c.Epoch)
+	if epochStartSlot > baseState.Slot() {
+		if featureconfig.Get().EnableNextSlotStateCache {
+			baseState, err = state.ProcessSlotsUsingNextSlotCache(ctx, baseState, c.Root, epochStartSlot)
+			if err != nil {
+				return nil, errors.Wrapf(err, "could not process slots up to epoch %d", c.Epoch)
+			}
+		} else {
+			baseState, err = state.ProcessSlots(ctx, baseState, epochStartSlot)
+			if err != nil {
+				return nil, errors.Wrapf(err, "could not process slots up to epoch %d", c.Epoch)
+			}
+		}
+		if err := s.checkpointStateCache.AddCheckpointState(c, baseState); err != nil {
+			return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
+		}
+		return baseState, nil
 	}

-	// Sharing the same state across caches is perfectly fine here, the fetching
-	// of attestation prestate is by far the most accessed state fetching pattern in
-	// the beacon node. An extra state instance cached isn't an issue in the bigger
-	// picture.
-	if err := s.checkpointStateCache.AddCheckpointState(c, baseState); err != nil {
-		return nil, errors.Wrap(err, "could not save checkpoint state to cache")
+	// To avoid sharing the same state across checkpoint state cache and hot state cache,
+	// we don't add the state to check point cache.
+	has, err := s.cfg.StateGen.HasStateInCache(ctx, bytesutil.ToBytes32(c.Root))
+	if err != nil {
+		return nil, err
+	}
+	if !has {
+		if err := s.checkpointStateCache.AddCheckpointState(c, baseState); err != nil {
+			return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
+		}
 	}
 	return baseState, nil

 }

 // verifyAttTargetEpoch validates attestation is from the current or previous epoch.
-func verifyAttTargetEpoch(_ context.Context, genesisTime, nowTime uint64, c *ethpb.Checkpoint) error {
+func (s *Service) verifyAttTargetEpoch(_ context.Context, genesisTime, nowTime uint64, c *ethpb.Checkpoint) error {
 	currentSlot := types.Slot((nowTime - genesisTime) / params.BeaconConfig().SecondsPerSlot)
-	currentEpoch := slots.ToEpoch(currentSlot)
+	currentEpoch := helpers.SlotToEpoch(currentSlot)
 	var prevEpoch types.Epoch
 	// Prevents previous epoch under flow
 	if currentEpoch > 1 {
@@ -85,7 +102,7 @@ func (s *Service) verifyBeaconBlock(ctx context.Context, data *ethpb.Attestation
 	if (b == nil || b.IsNil()) && s.hasInitSyncBlock(r) {
 		b = s.getInitSyncBlock(r)
 	}
-	if err := helpers.BeaconBlockIsNil(b); err != nil {
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
 		return err
 	}
 	if b.Block().Slot() > data.Slot {
--- a/beacon-chain/blockchain/process_attestation_test.go
+++ b/beacon-chain/blockchain/process_attestation_test.go
@@ -3,72 +3,65 @@ package blockchain
 import (
 	"context"
 	"testing"
-	"time"

 	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 )

-func TestStore_OnAttestation_ErrorConditions_ProtoArray(t *testing.T) {
+func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)

-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(protoarray.New(0, 0, [32]byte{})),
-		WithStateGen(stategen.New(beaconDB)),
+	cfg := &Config{
+		BeaconDB:        beaconDB,
+		ForkChoiceStore: protoarray.New(0, 0, [32]byte{}),
+		StateGen:        stategen.New(beaconDB),
 	}
-	service, err := NewService(ctx, opts...)
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

 	_, err = blockTree1(t, beaconDB, []byte{'g'})
 	require.NoError(t, err)

-	BlkWithOutState := util.NewBeaconBlock()
+	BlkWithOutState := testutil.NewBeaconBlock()
 	BlkWithOutState.Block.Slot = 0
-	wsb, err := wrapper.WrappedSignedBeaconBlock(BlkWithOutState)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(BlkWithOutState)))
 	BlkWithOutStateRoot, err := BlkWithOutState.Block.HashTreeRoot()
 	require.NoError(t, err)

-	BlkWithStateBadAtt := util.NewBeaconBlock()
+	BlkWithStateBadAtt := testutil.NewBeaconBlock()
 	BlkWithStateBadAtt.Block.Slot = 1
-	wsb, err = wrapper.WrappedSignedBeaconBlock(BlkWithStateBadAtt)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(BlkWithStateBadAtt)))
 	BlkWithStateBadAttRoot, err := BlkWithStateBadAtt.Block.HashTreeRoot()
 	require.NoError(t, err)

-	s, err := util.NewBeaconState()
+	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, s.SetSlot(100*params.BeaconConfig().SlotsPerEpoch))
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot))

-	BlkWithValidState := util.NewBeaconBlock()
+	BlkWithValidState := testutil.NewBeaconBlock()
 	BlkWithValidState.Block.Slot = 2
-	wsb, err = wrapper.WrappedSignedBeaconBlock(BlkWithValidState)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(BlkWithValidState)))

 	BlkWithValidStateRoot, err := BlkWithValidState.Block.HashTreeRoot()
 	require.NoError(t, err)
-	s, err = util.NewBeaconState()
+	s, err = testutil.NewBeaconState()
 	require.NoError(t, err)
-	err = s.SetFork(&ethpb.Fork{
+	err = s.SetFork(&pb.Fork{
 		Epoch:           0,
 		CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
 		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
@@ -83,17 +76,17 @@ func TestStore_OnAttestation_ErrorConditions_ProtoArray(t *testing.T) {
 	}{
 		{
 			name:      "attestation's data slot not aligned with target vote",
-			a:         util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Root: make([]byte, 32)}}}),
+			a:         testutil.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Root: make([]byte, 32)}}}),
 			wantedErr: "slot 32 does not match target epoch 0",
 		},
 		{
 			name:      "no pre state for attestations's target block",
-			a:         util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: BlkWithOutStateRoot[:]}}}),
+			a:         testutil.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: BlkWithOutStateRoot[:]}}}),
 			wantedErr: "could not get pre state for epoch 0",
 		},
 		{
 			name: "process attestation doesn't match current epoch",
-			a: util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: 100 * params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Epoch: 100,
+			a: testutil.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: 100 * params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Epoch: 100,
 				Root: BlkWithStateBadAttRoot[:]}}}),
 			wantedErr: "target epoch 100 does not match current epoch",
 		},
@@ -111,9 +104,9 @@ func TestStore_OnAttestation_ErrorConditions_ProtoArray(t *testing.T) {
 			name: "process nil field (a.Target) in attestation",
 			a: &ethpb.Attestation{
 				Data: &ethpb.AttestationData{
-					BeaconBlockRoot: make([]byte, fieldparams.RootLength),
+					BeaconBlockRoot: make([]byte, 32),
 					Target:          nil,
-					Source:          &ethpb.Checkpoint{Root: make([]byte, fieldparams.RootLength)},
+					Source:          &ethpb.Checkpoint{Root: make([]byte, 32)},
 				},
 				AggregationBits: make([]byte, 1),
 				Signature:       make([]byte, 96),
@@ -124,7 +117,7 @@ func TestStore_OnAttestation_ErrorConditions_ProtoArray(t *testing.T) {

 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			err := service.OnAttestation(ctx, tt.a)
+			err := service.onAttestation(ctx, tt.a)
 			if tt.wantedErr != "" {
 				assert.ErrorContains(t, tt.wantedErr, err)
 			} else {
@@ -134,188 +127,49 @@ func TestStore_OnAttestation_ErrorConditions_ProtoArray(t *testing.T) {
 	}
 }

-func TestStore_OnAttestation_ErrorConditions_DoublyLinkedTree(t *testing.T) {
+func TestStore_OnAttestation_Ok(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)

-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(doublylinkedtree.New(0, 0)),
-		WithStateGen(stategen.New(beaconDB)),
+	cfg := &Config{
+		BeaconDB:        beaconDB,
+		ForkChoiceStore: protoarray.New(0, 0, [32]byte{}),
+		StateGen:        stategen.New(beaconDB),
 	}
-	service, err := NewService(ctx, opts...)
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)
-
-	_, err = blockTree1(t, beaconDB, []byte{'g'})
-	require.NoError(t, err)
-
-	BlkWithOutState := util.NewBeaconBlock()
-	BlkWithOutState.Block.Slot = 0
-	wsb, err := wrapper.WrappedSignedBeaconBlock(BlkWithOutState)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-	BlkWithOutStateRoot, err := BlkWithOutState.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	BlkWithStateBadAtt := util.NewBeaconBlock()
-	BlkWithStateBadAtt.Block.Slot = 1
-	wsb, err = wrapper.WrappedSignedBeaconBlock(BlkWithStateBadAtt)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-	BlkWithStateBadAttRoot, err := BlkWithStateBadAtt.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	s, err := util.NewBeaconState()
-	require.NoError(t, err)
-	require.NoError(t, s.SetSlot(100*params.BeaconConfig().SlotsPerEpoch))
-	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot))
-
-	BlkWithValidState := util.NewBeaconBlock()
-	BlkWithValidState.Block.Slot = 2
-	wsb, err = wrapper.WrappedSignedBeaconBlock(BlkWithValidState)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-
-	BlkWithValidStateRoot, err := BlkWithValidState.Block.HashTreeRoot()
-	require.NoError(t, err)
-	s, err = util.NewBeaconState()
-	require.NoError(t, err)
-	err = s.SetFork(&ethpb.Fork{
-		Epoch:           0,
-		CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
-		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
-	})
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithValidStateRoot))
-
-	tests := []struct {
-		name      string
-		a         *ethpb.Attestation
-		wantedErr string
-	}{
-		{
-			name:      "attestation's data slot not aligned with target vote",
-			a:         util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Root: make([]byte, 32)}}}),
-			wantedErr: "slot 32 does not match target epoch 0",
-		},
-		{
-			name:      "no pre state for attestations's target block",
-			a:         util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: BlkWithOutStateRoot[:]}}}),
-			wantedErr: "could not get pre state for epoch 0",
-		},
-		{
-			name: "process attestation doesn't match current epoch",
-			a: util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: 100 * params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Epoch: 100,
-				Root: BlkWithStateBadAttRoot[:]}}}),
-			wantedErr: "target epoch 100 does not match current epoch",
-		},
-		{
-			name:      "process nil attestation",
-			a:         nil,
-			wantedErr: "attestation can't be nil",
-		},
-		{
-			name:      "process nil field (a.Data) in attestation",
-			a:         &ethpb.Attestation{},
-			wantedErr: "attestation's data can't be nil",
-		},
-		{
-			name: "process nil field (a.Target) in attestation",
-			a: &ethpb.Attestation{
-				Data: &ethpb.AttestationData{
-					BeaconBlockRoot: make([]byte, fieldparams.RootLength),
-					Target:          nil,
-					Source:          &ethpb.Checkpoint{Root: make([]byte, fieldparams.RootLength)},
-				},
-				AggregationBits: make([]byte, 1),
-				Signature:       make([]byte, 96),
-			},
-			wantedErr: "attestation's target can't be nil",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			err := service.OnAttestation(ctx, tt.a)
-			if tt.wantedErr != "" {
-				assert.ErrorContains(t, tt.wantedErr, err)
-			} else {
-				assert.NoError(t, err)
-			}
-		})
-	}
-}
-
-func TestStore_OnAttestation_Ok_ProtoArray(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	genesisState, pks := util.DeterministicGenesisState(t, 64)
-	service.SetGenesisTime(time.Unix(time.Now().Unix()-int64(params.BeaconConfig().SecondsPerSlot), 0))
+	genesisState, pks := testutil.DeterministicGenesisState(t, 64)
+	require.NoError(t, genesisState.SetGenesisTime(uint64(timeutils.Now().Unix())-params.BeaconConfig().SecondsPerSlot))
 	require.NoError(t, service.saveGenesisData(ctx, genesisState))
-	att, err := util.GenerateAttestations(genesisState, pks, 1, 0, false)
+	att, err := testutil.GenerateAttestations(genesisState, pks, 1, 0, false)
 	require.NoError(t, err)
 	tRoot := bytesutil.ToBytes32(att[0].Data.Target.Root)
 	copied := genesisState.Copy()
-	copied, err = transition.ProcessSlots(ctx, copied, 1)
+	copied, err = state.ProcessSlots(ctx, copied, 1)
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
-	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 0, tRoot, tRoot, params.BeaconConfig().ZeroHash, 1, 1))
-	require.NoError(t, service.OnAttestation(ctx, att[0]))
-}
-
-func TestStore_OnAttestation_Ok_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fcs := doublylinkedtree.New(0, 0)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	genesisState, pks := util.DeterministicGenesisState(t, 64)
-	service.SetGenesisTime(time.Unix(time.Now().Unix()-int64(params.BeaconConfig().SecondsPerSlot), 0))
-	require.NoError(t, service.saveGenesisData(ctx, genesisState))
-	att, err := util.GenerateAttestations(genesisState, pks, 1, 0, false)
-	require.NoError(t, err)
-	tRoot := bytesutil.ToBytes32(att[0].Data.Target.Root)
-	copied := genesisState.Copy()
-	copied, err = transition.ProcessSlots(ctx, copied, 1)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
-	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 0, tRoot, tRoot, params.BeaconConfig().ZeroHash, 1, 1))
-	require.NoError(t, service.OnAttestation(ctx, att[0]))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
+	require.NoError(t, service.onAttestation(ctx, att[0]))
 }

 func TestStore_SaveCheckpointState(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)

-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
+	cfg := &Config{
+		BeaconDB: beaconDB,
+		StateGen: stategen.New(beaconDB),
 	}
-	service, err := NewService(ctx, opts...)
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	s, err := util.NewBeaconState()
+	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	err = s.SetFinalizedCheckpoint(&ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'A'}, fieldparams.RootLength)})
+	err = s.SetFinalizedCheckpoint(&ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'A'}, 32)})
 	require.NoError(t, err)
 	val := &ethpb.Validator{
 		PublicKey:             bytesutil.PadTo([]byte("foo"), 48),
-		WithdrawalCredentials: bytesutil.PadTo([]byte("bar"), fieldparams.RootLength),
+		WithdrawalCredentials: bytesutil.PadTo([]byte("bar"), 32),
 	}
 	err = s.SetValidators([]*ethpb.Validator{val})
 	require.NoError(t, err)
@@ -324,23 +178,23 @@ func TestStore_SaveCheckpointState(t *testing.T) {
 	r := [32]byte{'g'}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, r))

-	service.store.SetJustifiedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	service.store.SetBestJustifiedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	service.store.SetPrevFinalizedCheckpt(&ethpb.Checkpoint{Root: r[:]})
+	service.justifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.bestJustifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.finalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.prevFinalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}

 	r = bytesutil.ToBytes32([]byte{'A'})
-	cp1 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'A'}, fieldparams.RootLength)}
+	cp1 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'A'}, 32)}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'A'})))
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Root: bytesutil.PadTo([]byte{'A'}, fieldparams.RootLength)}))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'A'}, 32)}))

 	s1, err := service.getAttPreState(ctx, cp1)
 	require.NoError(t, err)
 	assert.Equal(t, 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot(), "Unexpected state slot")

-	cp2 := &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'B'}, fieldparams.RootLength)}
+	cp2 := &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'B'}, 32)}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'B'})))
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Root: bytesutil.PadTo([]byte{'B'}, fieldparams.RootLength)}))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'B'}, 32)}))
 	s2, err := service.getAttPreState(ctx, cp2)
 	require.NoError(t, err)
 	assert.Equal(t, 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot(), "Unexpected state slot")
@@ -358,13 +212,13 @@ func TestStore_SaveCheckpointState(t *testing.T) {
 	assert.Equal(t, 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot(), "Unexpected state slot")

 	require.NoError(t, s.SetSlot(params.BeaconConfig().SlotsPerEpoch+1))
-	service.store.SetJustifiedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	service.store.SetBestJustifiedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	service.store.SetPrevFinalizedCheckpt(&ethpb.Checkpoint{Root: r[:]})
-	cp3 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'C'}, fieldparams.RootLength)}
+	service.justifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.bestJustifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.finalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.prevFinalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	cp3 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'C'}, 32)}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'C'})))
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Root: bytesutil.PadTo([]byte{'C'}, fieldparams.RootLength)}))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'C'}, 32)}))
 	s3, err := service.getAttPreState(ctx, cp3)
 	require.NoError(t, err)
 	assert.Equal(t, s.Slot(), s3.Slot(), "Unexpected state slot")
@@ -374,16 +228,16 @@ func TestStore_UpdateCheckpointState(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)

-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
+	cfg := &Config{
+		BeaconDB: beaconDB,
+		StateGen: stategen.New(beaconDB),
 	}
-	service, err := NewService(ctx, opts...)
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

 	epoch := types.Epoch(1)
-	baseState, _ := util.DeterministicGenesisState(t, 1)
-	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("hi"), fieldparams.RootLength)}
+	baseState, _ := testutil.DeterministicGenesisState(t, 1)
+	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("hi"), 32)}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)))
 	returned, err := service.getAttPreState(ctx, checkpoint)
 	require.NoError(t, err)
@@ -394,13 +248,13 @@ func TestStore_UpdateCheckpointState(t *testing.T) {
 	assert.Equal(t, returned.Slot(), cached.Slot(), "State should have been cached")

 	epoch = 2
-	newCheckpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("bye"), fieldparams.RootLength)}
+	newCheckpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("bye"), 32)}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(newCheckpoint.Root)))
 	returned, err = service.getAttPreState(ctx, newCheckpoint)
 	require.NoError(t, err)
-	s, err := slots.EpochStart(newCheckpoint.Epoch)
+	s, err := helpers.StartSlot(newCheckpoint.Epoch)
 	require.NoError(t, err)
-	baseState, err = transition.ProcessSlots(ctx, baseState, s)
+	baseState, err = state.ProcessSlots(ctx, baseState, s)
 	require.NoError(t, err)
 	assert.Equal(t, returned.Slot(), baseState.Slot(), "Incorrectly returned base state")

@@ -411,48 +265,64 @@ func TestStore_UpdateCheckpointState(t *testing.T) {

 func TestAttEpoch_MatchPrevEpoch(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{BeaconDB: beaconDB}
+	service, err := NewService(ctx, cfg)
+	require.NoError(t, err)

 	nowTime := uint64(params.BeaconConfig().SlotsPerEpoch) * params.BeaconConfig().SecondsPerSlot
-	require.NoError(t, verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Root: make([]byte, fieldparams.RootLength)}))
+	require.NoError(t, service.verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Root: make([]byte, 32)}))
 }

 func TestAttEpoch_MatchCurrentEpoch(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{BeaconDB: beaconDB}
+	service, err := NewService(ctx, cfg)
+	require.NoError(t, err)

 	nowTime := uint64(params.BeaconConfig().SlotsPerEpoch) * params.BeaconConfig().SecondsPerSlot
-	require.NoError(t, verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Epoch: 1}))
+	require.NoError(t, service.verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Epoch: 1}))
 }

 func TestAttEpoch_NotMatch(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{BeaconDB: beaconDB}
+	service, err := NewService(ctx, cfg)
+	require.NoError(t, err)

 	nowTime := 2 * uint64(params.BeaconConfig().SlotsPerEpoch) * params.BeaconConfig().SecondsPerSlot
-	err := verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Root: make([]byte, fieldparams.RootLength)})
+	err = service.verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Root: make([]byte, 32)})
 	assert.ErrorContains(t, "target epoch 0 does not match current epoch 2 or prev epoch 1", err)
 }

 func TestVerifyBeaconBlock_NoBlock(t *testing.T) {
 	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{BeaconDB: beaconDB}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	d := util.HydrateAttestationData(&ethpb.AttestationData{})
+	d := testutil.HydrateAttestationData(&ethpb.AttestationData{})
 	assert.ErrorContains(t, "signed beacon block can't be nil", service.verifyBeaconBlock(ctx, d))
 }

 func TestVerifyBeaconBlock_futureBlock(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)

-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
+	cfg := &Config{BeaconDB: beaconDB}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	b := util.NewBeaconBlock()
+	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 2
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b)))
 	r, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
 	d := &ethpb.AttestationData{Slot: 1, BeaconBlockRoot: r[:]}
@@ -462,16 +332,15 @@ func TestVerifyBeaconBlock_futureBlock(t *testing.T) {

 func TestVerifyBeaconBlock_OK(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)

-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
+	cfg := &Config{BeaconDB: beaconDB}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	b := util.NewBeaconBlock()
+	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 2
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b)))
 	r, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
 	d := &ethpb.AttestationData{Slot: 2, BeaconBlockRoot: r[:]}
@@ -479,69 +348,26 @@ func TestVerifyBeaconBlock_OK(t *testing.T) {
 	assert.NoError(t, service.verifyBeaconBlock(ctx, d), "Did not receive the wanted error")
 }

-func TestVerifyFinalizedConsistency_InconsistentRoot_ProtoArray(t *testing.T) {
+func TestVerifyFinalizedConsistency_InconsistentRoot(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)

-	fcs := protoarray.New(0, 0, [32]byte{'a'})
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	b32 := util.NewBeaconBlock()
+	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b32)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b32)))
 	r32, err := b32.Block.HashTreeRoot()
 	require.NoError(t, err)

-	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 1})
-	b33 := util.NewBeaconBlock()
+	service.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 1}
+
+	b33 := testutil.NewBeaconBlock()
 	b33.Block.Slot = 33
 	b33.Block.ParentRoot = r32[:]
-	wsb, err = wrapper.WrappedSignedBeaconBlock(b33)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
-	r33, err := b33.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
-	require.ErrorContains(t, "Root and finalized store are not consistent", err)
-}
-
-func TestVerifyFinalizedConsistency_InconsistentRoot_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fcs := doublylinkedtree.New(0, 0)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	b32 := util.NewBeaconBlock()
-	b32.Block.Slot = 32
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b32)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
-	r32, err := b32.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 1})
-	b33 := util.NewBeaconBlock()
-	b33.Block.Slot = 33
-	b33.Block.ParentRoot = r32[:]
-	wsb, err = wrapper.WrappedSignedBeaconBlock(b33)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b33)))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -551,27 +377,24 @@ func TestVerifyFinalizedConsistency_InconsistentRoot_DoublyLinkedTree(t *testing

 func TestVerifyFinalizedConsistency_OK(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)

-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	b32 := util.NewBeaconBlock()
+	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b32)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b32)))
 	r32, err := b32.Block.HashTreeRoot()
 	require.NoError(t, err)

-	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: r32[:], Epoch: 1})
+	service.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 1, Root: r32[:]}

-	b33 := util.NewBeaconBlock()
+	b33 := testutil.NewBeaconBlock()
 	b33.Block.Slot = 33
 	b33.Block.ParentRoot = r32[:]
-	wsb, err = wrapper.WrappedSignedBeaconBlock(b33)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b33)))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -581,26 +404,27 @@ func TestVerifyFinalizedConsistency_OK(t *testing.T) {

 func TestVerifyFinalizedConsistency_IsCanonical(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)

-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	b32 := util.NewBeaconBlock()
+	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
 	r32, err := b32.Block.HashTreeRoot()
 	require.NoError(t, err)

-	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: r32[:], Epoch: 1})
+	service.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 1, Root: r32[:]}

-	b33 := util.NewBeaconBlock()
+	b33 := testutil.NewBeaconBlock()
 	b33.Block.Slot = 33
 	b33.Block.ParentRoot = r32[:]
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

-	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, b32.Block.Slot, r32, [32]byte{}, params.BeaconConfig().ZeroHash, 0, 0))
-	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, b33.Block.Slot, r33, r32, params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, b32.Block.Slot, r32, [32]byte{}, [32]byte{}, 0, 0))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, b33.Block.Slot, r33, r32, [32]byte{}, 0, 0))

 	_, err = service.cfg.ForkChoiceStore.Head(ctx, 0, r32, []uint64{}, 0)
 	require.NoError(t, err)
--- a/beacon-chain/blockchain/process_block.go
+++ b/beacon-chain/blockchain/process_block.go
@@ -6,25 +6,20 @@ import (
 	"time"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	coreTime "github.com/prysmaticlabs/prysm/beacon-chain/core/time"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
-	forkchoicetypes "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/config/features"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/crypto/bls"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/monitoring/tracing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	ethpbv1 "github.com/prysmaticlabs/prysm/proto/eth/v1"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/attestation"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/runtime/version"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
 	"go.opencensus.io/trace"
 )

@@ -88,11 +83,12 @@ var initialSyncBlockCacheSize = uint64(2 * params.BeaconConfig().SlotsPerEpoch)
 //            ancestor_at_finalized_slot = get_ancestor(store, store.justified_checkpoint.root, finalized_slot)
 //            if ancestor_at_finalized_slot != store.finalized_checkpoint.root:
 //                store.justified_checkpoint = state.current_justified_checkpoint
-func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, blockRoot [32]byte) error {
+func (s *Service) onBlock(ctx context.Context, signed interfaces.SignedBeaconBlock, blockRoot [32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlock")
 	defer span.End()
-	if err := helpers.BeaconBlockIsNil(signed); err != nil {
-		return err
+
+	if signed == nil || signed.IsNil() || signed.Block().IsNil() {
+		return errors.New("nil block")
 	}
 	b := signed.Block()

@@ -101,152 +97,60 @@ func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, b
 		return err
 	}

-	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
+	postState, err := state.ExecuteStateTransition(ctx, preState, signed)
 	if err != nil {
 		return err
 	}
-	postState, err := transition.ExecuteStateTransition(ctx, preState, signed)
-	if err != nil {
-		return err
-	}
-	postStateVersion, postStateHeader, err := getStateVersionAndPayload(postState)
-	if err != nil {
-		return err
-	}
-	isValidPayload, err := s.notifyNewPayload(ctx, preStateVersion, postStateVersion, preStateHeader, postStateHeader, signed)
-	if err != nil {
-		return errors.Wrap(err, "could not verify new payload")
-	}
-	if !isValidPayload {
-		candidate, err := s.optimisticCandidateBlock(ctx, b)
-		if err != nil {
-			return errors.Wrap(err, "could not check if block is optimistic candidate")
-		}
-		if !candidate {
-			return errNotOptimisticCandidate
-		}
-	}

 	if err := s.savePostStateInfo(ctx, blockRoot, signed, postState, false /* reg sync */); err != nil {
 		return err
 	}
-	if isValidPayload {
-		if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, blockRoot); err != nil {
-			return errors.Wrap(err, "could not set optimistic block to valid")
-		}
-	}

-	// We add a proposer score boost to fork choice for the block root if applicable, right after
-	// running a successful state transition for the block.
-	secondsIntoSlot := uint64(time.Since(s.genesisTime).Seconds()) % params.BeaconConfig().SecondsPerSlot
-	if err := s.cfg.ForkChoiceStore.BoostProposerRoot(ctx, &forkchoicetypes.ProposerBoostRootArgs{
-		BlockRoot:       blockRoot,
-		BlockSlot:       signed.Block().Slot(),
-		CurrentSlot:     slots.SinceGenesis(s.genesisTime),
-		SecondsIntoSlot: secondsIntoSlot,
-	}); err != nil {
-		return err
-	}
-
-	// If slasher is configured, forward the attestations in the block via
-	// an event feed for processing.
-	if features.Get().EnableSlasher {
-		// Feed the indexed attestation to slasher if enabled. This action
-		// is done in the background to avoid adding more load to this critical code path.
+	// Updating next slot state cache can happen in the background. It shouldn't block rest of the process.
+	if featureconfig.Get().EnableNextSlotStateCache {
 		go func() {
-			// Using a different context to prevent timeouts as this operation can be expensive
-			// and we want to avoid affecting the critical code path.
-			ctx := context.TODO()
-			for _, att := range signed.Block().Body().Attestations() {
-				committee, err := helpers.BeaconCommitteeFromState(ctx, preState, att.Data.Slot, att.Data.CommitteeIndex)
-				if err != nil {
-					log.WithError(err).Error("Could not get attestation committee")
-					tracing.AnnotateError(span, err)
-					return
-				}
-				indexedAtt, err := attestation.ConvertToIndexed(ctx, att, committee)
-				if err != nil {
-					log.WithError(err).Error("Could not convert to indexed attestation")
-					tracing.AnnotateError(span, err)
-					return
-				}
-				s.cfg.SlasherAttestationsFeed.Send(indexedAtt)
+			// Use a custom deadline here, since this method runs asynchronously.
+			// We ignore the parent method's context and instead create a new one
+			// with a custom deadline, therefore using the background context instead.
+			slotCtx, cancel := context.WithTimeout(context.Background(), slotDeadline)
+			defer cancel()
+			if err := state.UpdateNextSlotCache(slotCtx, blockRoot[:], postState); err != nil {
+				log.WithError(err).Debug("could not update next slot state cache")
 			}
 		}()
 	}

 	// Update justified check point.
-	justified := s.store.JustifiedCheckpt()
-	if justified == nil {
-		return errNilJustifiedInStore
-	}
-	currJustifiedEpoch := justified.Epoch
-	if postState.CurrentJustifiedCheckpoint().Epoch > currJustifiedEpoch {
+	if postState.CurrentJustifiedCheckpoint().Epoch > s.justifiedCheckpt.Epoch {
 		if err := s.updateJustified(ctx, postState); err != nil {
 			return err
 		}
 	}

-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
-	newFinalized := postState.FinalizedCheckpointEpoch() > finalized.Epoch
-	if newFinalized {
-		s.store.SetPrevFinalizedCheckpt(finalized)
-		s.store.SetFinalizedCheckpt(postState.FinalizedCheckpoint())
-		s.store.SetPrevJustifiedCheckpt(justified)
-		s.store.SetJustifiedCheckpt(postState.CurrentJustifiedCheckpoint())
-	}
-
-	balances, err := s.justifiedBalances.get(ctx, bytesutil.ToBytes32(justified.Root))
-	if err != nil {
-		msg := fmt.Sprintf("could not read balances for state w/ justified checkpoint %#x", justified.Root)
-		return errors.Wrap(err, msg)
-	}
-	headRoot, err := s.updateHead(ctx, balances)
-	if err != nil {
-		log.WithError(err).Warn("Could not update head")
-	}
-	if _, err := s.notifyForkchoiceUpdate(ctx, s.headBlock().Block(), s.headRoot(), bytesutil.ToBytes32(finalized.Root)); err != nil {
-		return err
-	}
-	if err := s.saveHead(ctx, headRoot); err != nil {
-		return errors.Wrap(err, "could not save head")
-	}
-
-	if err := s.pruneCanonicalAttsFromPool(ctx, blockRoot, signed); err != nil {
-		return err
-	}
-
-	// Send notification of the processed block to the state feed.
-	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			Slot:        signed.Block().Slot(),
-			BlockRoot:   blockRoot,
-			SignedBlock: signed,
-			Verified:    true,
-		},
-	})
-
-	// Updating next slot state cache can happen in the background. It shouldn't block rest of the process.
-	go func() {
-		// Use a custom deadline here, since this method runs asynchronously.
-		// We ignore the parent method's context and instead create a new one
-		// with a custom deadline, therefore using the background context instead.
-		slotCtx, cancel := context.WithTimeout(context.Background(), slotDeadline)
-		defer cancel()
-		if err := transition.UpdateNextSlotCache(slotCtx, blockRoot[:], postState); err != nil {
-			log.WithError(err).Debug("could not update next slot state cache")
+	newFinalized := postState.FinalizedCheckpointEpoch() > s.finalizedCheckpt.Epoch
+	if featureconfig.Get().UpdateHeadTimely {
+		if newFinalized {
+			if err := s.finalizedImpliesNewJustified(ctx, postState); err != nil {
+				return errors.Wrap(err, "could not save new justified")
+			}
+			s.prevFinalizedCheckpt = s.finalizedCheckpt
+			s.finalizedCheckpt = postState.FinalizedCheckpoint()
 		}
-	}()

-	// Save justified check point to db.
-	if postState.CurrentJustifiedCheckpoint().Epoch > currJustifiedEpoch {
-		if err := s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, postState.CurrentJustifiedCheckpoint()); err != nil {
-			return err
+		if err := s.updateHead(ctx, s.getJustifiedBalances()); err != nil {
+			log.WithError(err).Warn("Could not update head")
 		}
+
+		// Send notification of the processed block to the state feed.
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+			Type: statefeed.BlockProcessed,
+			Data: &statefeed.BlockProcessedData{
+				Slot:        signed.Block().Slot(),
+				BlockRoot:   blockRoot,
+				SignedBlock: signed,
+				Verified:    true,
+			},
+		})
 	}

 	// Update finalized check point.
@@ -258,19 +162,19 @@ func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, b
 		if err := s.cfg.ForkChoiceStore.Prune(ctx, fRoot); err != nil {
 			return errors.Wrap(err, "could not prune proto array fork choice nodes")
 		}
-		isOptimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(ctx, fRoot)
-		if err != nil {
-			return errors.Wrap(err, "could not check if node is optimistically synced")
+		if !featureconfig.Get().UpdateHeadTimely {
+			if err := s.finalizedImpliesNewJustified(ctx, postState); err != nil {
+				return errors.Wrap(err, "could not save new justified")
+			}
 		}
 		go func() {
 			// Send an event regarding the new finalized checkpoint over a common event feed.
 			s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 				Type: statefeed.FinalizedCheckpoint,
 				Data: &ethpbv1.EventFinalizedCheckpoint{
-					Epoch:               postState.FinalizedCheckpoint().Epoch,
-					Block:               postState.FinalizedCheckpoint().Root,
-					State:               signed.Block().StateRoot(),
-					ExecutionOptimistic: isOptimistic,
+					Epoch: postState.FinalizedCheckpoint().Epoch,
+					Block: postState.FinalizedCheckpoint().Root,
+					State: signed.Block().StateRoot(),
 				},
 			})

@@ -291,25 +195,7 @@ func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, b
 	return s.handleEpochBoundary(ctx, postState)
 }

-func getStateVersionAndPayload(st state.BeaconState) (int, *ethpb.ExecutionPayloadHeader, error) {
-	if st == nil {
-		return 0, nil, errors.New("nil state")
-	}
-	var preStateHeader *ethpb.ExecutionPayloadHeader
-	var err error
-	preStateVersion := st.Version()
-	switch preStateVersion {
-	case version.Phase0, version.Altair:
-	default:
-		preStateHeader, err = st.LatestExecutionPayloadHeader()
-		if err != nil {
-			return 0, nil, err
-		}
-	}
-	return preStateVersion, preStateHeader, nil
-}
-
-func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlock,
+func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.SignedBeaconBlock,
 	blockRoots [][32]byte) ([]*ethpb.Checkpoint, []*ethpb.Checkpoint, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlockBatch")
 	defer span.End()
@@ -317,13 +203,8 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlo
 	if len(blks) == 0 || len(blockRoots) == 0 {
 		return nil, nil, errors.New("no blocks provided")
 	}
-
-	if len(blks) != len(blockRoots) {
-		return nil, nil, errWrongBlockCount
-	}
-
-	if err := helpers.BeaconBlockIsNil(blks[0]); err != nil {
-		return nil, nil, err
+	if blks[0] == nil || blks[0].IsNil() || blks[0].Block().IsNil() {
+		return nil, nil, errors.New("nil block")
 	}
 	b := blks[0].Block()

@@ -341,48 +222,27 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlo

 	jCheckpoints := make([]*ethpb.Checkpoint, len(blks))
 	fCheckpoints := make([]*ethpb.Checkpoint, len(blks))
-	sigSet := &bls.SignatureBatch{
+	sigSet := &bls.SignatureSet{
 		Signatures: [][]byte{},
 		PublicKeys: []bls.PublicKey{},
 		Messages:   [][32]byte{},
 	}
-	type versionAndHeader struct {
-		version int
-		header  *ethpb.ExecutionPayloadHeader
-	}
-	preVersionAndHeaders := make([]*versionAndHeader, len(blks))
-	postVersionAndHeaders := make([]*versionAndHeader, len(blks))
-	var set *bls.SignatureBatch
-	boundaries := make(map[[32]byte]state.BeaconState)
+	var set *bls.SignatureSet
+	boundaries := make(map[[32]byte]iface.BeaconState)
 	for i, b := range blks {
-		v, h, err := getStateVersionAndPayload(preState)
-		if err != nil {
-			return nil, nil, err
-		}
-		preVersionAndHeaders[i] = &versionAndHeader{
-			version: v,
-			header:  h,
-		}
-
-		set, preState, err = transition.ExecuteStateTransitionNoVerifyAnySig(ctx, preState, b)
+		set, preState, err = state.ExecuteStateTransitionNoVerifyAnySig(ctx, preState, b)
 		if err != nil {
 			return nil, nil, err
 		}
 		// Save potential boundary states.
-		if slots.IsEpochStart(preState.Slot()) {
+		if helpers.IsEpochStart(preState.Slot()) {
 			boundaries[blockRoots[i]] = preState.Copy()
+			if err := s.handleEpochBoundary(ctx, preState); err != nil {
+				return nil, nil, errors.Wrap(err, "could not handle epoch boundary state")
+			}
 		}
 		jCheckpoints[i] = preState.CurrentJustifiedCheckpoint()
 		fCheckpoints[i] = preState.FinalizedCheckpoint()
-
-		v, h, err = getStateVersionAndPayload(preState)
-		if err != nil {
-			return nil, nil, err
-		}
-		postVersionAndHeaders[i] = &versionAndHeader{
-			version: v,
-			header:  h,
-		}
 		sigSet.Join(set)
 	}
 	verify, err := sigSet.Verify()
@@ -392,43 +252,6 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlo
 	if !verify {
 		return nil, nil, errors.New("batch block signature verification failed")
 	}
-
-	// blocks have been verified, add them to forkchoice and call the engine
-	for i, b := range blks {
-		s.saveInitSyncBlock(blockRoots[i], b)
-		isValidPayload, err := s.notifyNewPayload(ctx,
-			preVersionAndHeaders[i].version,
-			postVersionAndHeaders[i].version,
-			preVersionAndHeaders[i].header,
-			postVersionAndHeaders[i].header, b)
-
-		if err != nil {
-			return nil, nil, err
-		}
-		if !isValidPayload {
-			candidate, err := s.optimisticCandidateBlock(ctx, b.Block())
-			if err != nil {
-				return nil, nil, errors.Wrap(err, "could not check if block is optimistic candidate")
-			}
-			if !candidate {
-				return nil, nil, errNotOptimisticCandidate
-			}
-		}
-
-		if err := s.insertBlockToForkChoiceStore(ctx, b.Block(), blockRoots[i], fCheckpoints[i], jCheckpoints[i]); err != nil {
-			return nil, nil, err
-		}
-		if isValidPayload {
-			if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, blockRoots[i]); err != nil {
-				return nil, nil, errors.Wrap(err, "could not set optimistic block to valid")
-			}
-		}
-
-		if _, err := s.notifyForkchoiceUpdate(ctx, b.Block(), blockRoots[i], bytesutil.ToBytes32(fCheckpoints[i].Root)); err != nil {
-			return nil, nil, err
-		}
-	}
-
 	for r, st := range boundaries {
 		if err := s.cfg.StateGen.SaveState(ctx, r, st); err != nil {
 			return nil, nil, err
@@ -448,10 +271,15 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlo

 // handles a block after the block's batch has been verified, where we can save blocks
 // their state summaries and split them off to relative hot/cold storage.
-func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed block.SignedBeaconBlock,
+func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed interfaces.SignedBeaconBlock,
 	blockRoot [32]byte, fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
+	b := signed.Block()

-	if err := s.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{
+	s.saveInitSyncBlock(blockRoot, signed)
+	if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, fCheckpoint, jCheckpoint); err != nil {
+		return err
+	}
+	if err := s.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{
 		Slot: signed.Block().Slot(),
 		Root: blockRoot[:],
 	}); err != nil {
@@ -466,47 +294,34 @@ func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed block.
 		s.clearInitSyncBlocks()
 	}

-	justified := s.store.JustifiedCheckpt()
-	if justified == nil {
-		return errNilJustifiedInStore
-	}
-	if jCheckpoint.Epoch > justified.Epoch {
+	if jCheckpoint.Epoch > s.justifiedCheckpt.Epoch {
 		if err := s.updateJustifiedInitSync(ctx, jCheckpoint); err != nil {
 			return err
 		}
 	}

-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
 	// Update finalized check point. Prune the block cache and helper caches on every new finalized epoch.
-	if fCheckpoint.Epoch > finalized.Epoch {
+	if fCheckpoint.Epoch > s.finalizedCheckpt.Epoch {
 		if err := s.updateFinalized(ctx, fCheckpoint); err != nil {
 			return err
 		}
-		s.store.SetPrevFinalizedCheckpt(finalized)
-		s.store.SetFinalizedCheckpt(fCheckpoint)
 	}
 	return nil
 }

 // Epoch boundary bookkeeping such as logging epoch summaries.
-func (s *Service) handleEpochBoundary(ctx context.Context, postState state.BeaconState) error {
-	ctx, span := trace.StartSpan(ctx, "blockChain.handleEpochBoundary")
-	defer span.End()
-
+func (s *Service) handleEpochBoundary(ctx context.Context, postState iface.BeaconState) error {
 	if postState.Slot()+1 == s.nextEpochBoundarySlot {
 		// Update caches for the next epoch at epoch boundary slot - 1.
-		if err := helpers.UpdateCommitteeCache(postState, coreTime.NextEpoch(postState)); err != nil {
+		if err := helpers.UpdateCommitteeCache(postState, helpers.NextEpoch(postState)); err != nil {
 			return err
 		}
 		copied := postState.Copy()
-		copied, err := transition.ProcessSlots(ctx, copied, copied.Slot()+1)
+		copied, err := state.ProcessSlots(ctx, copied, copied.Slot()+1)
 		if err != nil {
 			return err
 		}
-		if err := helpers.UpdateProposerIndicesInCache(ctx, copied); err != nil {
+		if err := helpers.UpdateProposerIndicesInCache(copied); err != nil {
 			return err
 		}
 	} else if postState.Slot() >= s.nextEpochBoundarySlot {
@@ -514,17 +329,17 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco
 			return err
 		}
 		var err error
-		s.nextEpochBoundarySlot, err = slots.EpochStart(coreTime.NextEpoch(postState))
+		s.nextEpochBoundarySlot, err = helpers.StartSlot(helpers.NextEpoch(postState))
 		if err != nil {
 			return err
 		}

 		// Update caches at epoch boundary slot.
 		// The following updates have short cut to return nil cheaply if fulfilled during boundary slot - 1.
-		if err := helpers.UpdateCommitteeCache(postState, coreTime.CurrentEpoch(postState)); err != nil {
+		if err := helpers.UpdateCommitteeCache(postState, helpers.CurrentEpoch(postState)); err != nil {
 			return err
 		}
-		if err := helpers.UpdateProposerIndicesInCache(ctx, postState); err != nil {
+		if err := helpers.UpdateProposerIndicesInCache(postState); err != nil {
 			return err
 		}
 	}
@@ -534,11 +349,8 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco

 // This feeds in the block and block's attestations to fork choice store. It's allows fork choice store
 // to gain information on the most current chain.
-func (s *Service) insertBlockAndAttestationsToForkChoiceStore(ctx context.Context, blk block.BeaconBlock, root [32]byte,
-	st state.BeaconState) error {
-	ctx, span := trace.StartSpan(ctx, "blockChain.insertBlockAndAttestationsToForkChoiceStore")
-	defer span.End()
-
+func (s *Service) insertBlockAndAttestationsToForkChoiceStore(ctx context.Context, blk interfaces.BeaconBlock, root [32]byte,
+	st iface.BeaconState) error {
 	fCheckpoint := st.FinalizedCheckpoint()
 	jCheckpoint := st.CurrentJustifiedCheckpoint()
 	if err := s.insertBlockToForkChoiceStore(ctx, blk, root, fCheckpoint, jCheckpoint); err != nil {
@@ -546,11 +358,11 @@ func (s *Service) insertBlockAndAttestationsToForkChoiceStore(ctx context.Contex
 	}
 	// Feed in block's attestations to fork choice store.
 	for _, a := range blk.Body().Attestations() {
-		committee, err := helpers.BeaconCommitteeFromState(ctx, st, a.Data.Slot, a.Data.CommitteeIndex)
+		committee, err := helpers.BeaconCommitteeFromState(st, a.Data.Slot, a.Data.CommitteeIndex)
 		if err != nil {
 			return err
 		}
-		indices, err := attestation.AttestingIndices(a.AggregationBits, committee)
+		indices, err := attestationutil.AttestingIndices(a.AggregationBits, committee)
 		if err != nil {
 			return err
 		}
@@ -559,38 +371,24 @@ func (s *Service) insertBlockAndAttestationsToForkChoiceStore(ctx context.Contex
 	return nil
 }

-func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk block.BeaconBlock,
+func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk interfaces.BeaconBlock,
 	root [32]byte, fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
 	if err := s.fillInForkChoiceMissingBlocks(ctx, blk, fCheckpoint, jCheckpoint); err != nil {
 		return err
 	}
 	// Feed in block to fork choice store.
-
-	payloadHash, err := getBlockPayloadHash(blk)
-	if err != nil {
-		return err
-	}
-	return s.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx,
-		blk.Slot(), root, bytesutil.ToBytes32(blk.ParentRoot()), payloadHash,
+	if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
+		blk.Slot(), root, bytesutil.ToBytes32(blk.ParentRoot()), bytesutil.ToBytes32(blk.Body().Graffiti()),
 		jCheckpoint.Epoch,
-		fCheckpoint.Epoch)
-}
-
-func getBlockPayloadHash(blk block.BeaconBlock) ([32]byte, error) {
-	payloadHash := [32]byte{}
-	if blocks.IsPreBellatrixVersion(blk.Version()) {
-		return payloadHash, nil
+		fCheckpoint.Epoch); err != nil {
+		return errors.Wrap(err, "could not process block for proto array fork choice")
 	}
-	payload, err := blk.Body().ExecutionPayload()
-	if err != nil {
-		return payloadHash, err
-	}
-	return bytesutil.ToBytes32(payload.BlockHash), nil
+	return nil
 }

 // This saves post state info to DB or cache. This also saves post state info to fork choice store.
 // Post state info consists of processed block and state. Do not call this method unless the block and state are verified.
-func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b block.SignedBeaconBlock, st state.BeaconState, initSync bool) error {
+func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b interfaces.SignedBeaconBlock, st iface.BeaconState, initSync bool) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.savePostStateInfo")
 	defer span.End()
 	if initSync {
@@ -606,33 +404,3 @@ func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b block.Sig
 	}
 	return nil
 }
-
-// This removes the attestations from the mem pool. It will only remove the attestations if input root `r` is canonical,
-// meaning the block `b` is part of the canonical chain.
-func (s *Service) pruneCanonicalAttsFromPool(ctx context.Context, r [32]byte, b block.SignedBeaconBlock) error {
-	if !features.Get().CorrectlyPruneCanonicalAtts {
-		return nil
-	}
-
-	canonical, err := s.IsCanonical(ctx, r)
-	if err != nil {
-		return err
-	}
-	if !canonical {
-		return nil
-	}
-
-	atts := b.Block().Body().Attestations()
-	for _, att := range atts {
-		if helpers.IsAggregated(att) {
-			if err := s.cfg.AttPool.DeleteAggregatedAttestation(att); err != nil {
-				return err
-			}
-		} else {
-			if err := s.cfg.AttPool.DeleteUnaggregatedAttestation(att); err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}
--- a/beacon-chain/blockchain/process_block_helpers.go
+++ b/beacon-chain/blockchain/process_block_helpers.go
@@ -8,25 +8,26 @@ import (
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/monitoring/tracing"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/traceutil"
 	"go.opencensus.io/trace"
 )

 // CurrentSlot returns the current slot based on time.
 func (s *Service) CurrentSlot() types.Slot {
-	return slots.CurrentSlot(uint64(s.genesisTime.Unix()))
+	return helpers.CurrentSlot(uint64(s.genesisTime.Unix()))
 }

 // getBlockPreState returns the pre state of an incoming block. It uses the parent root of the block
 // to retrieve the state in DB. It verifies the pre state's validity and the incoming block
 // is in the correct time window.
-func (s *Service) getBlockPreState(ctx context.Context, b block.BeaconBlock) (state.BeaconState, error) {
+func (s *Service) getBlockPreState(ctx context.Context, b interfaces.BeaconBlock) (iface.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.getBlockPreState")
 	defer span.End()

@@ -44,7 +45,7 @@ func (s *Service) getBlockPreState(ctx context.Context, b block.BeaconBlock) (st
 	}

 	// Verify block slot time is not from the future.
-	if err := slots.VerifyTime(uint64(s.genesisTime.Unix()), b.Slot(), params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
+	if err := helpers.VerifySlotTime(preState.GenesisTime(), b.Slot(), params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
 		return nil, err
 	}

@@ -57,7 +58,7 @@ func (s *Service) getBlockPreState(ctx context.Context, b block.BeaconBlock) (st
 }

 // verifyBlkPreState validates input block has a valid pre-state.
-func (s *Service) verifyBlkPreState(ctx context.Context, b block.BeaconBlock) error {
+func (s *Service) verifyBlkPreState(ctx context.Context, b interfaces.BeaconBlock) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.verifyBlkPreState")
 	defer span.End()

@@ -91,11 +92,7 @@ func (s *Service) verifyBlkPreState(ctx context.Context, b block.BeaconBlock) er
 func (s *Service) VerifyBlkDescendant(ctx context.Context, root [32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.VerifyBlkDescendant")
 	defer span.End()
-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
-	fRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
+	fRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(s.finalizedCheckpt.Root))
 	finalizedBlkSigned, err := s.cfg.BeaconDB.Block(ctx, fRoot)
 	if err != nil {
 		return err
@@ -113,10 +110,10 @@ func (s *Service) VerifyBlkDescendant(ctx context.Context, root [32]byte) error
 	}

 	if !bytes.Equal(bFinalizedRoot, fRoot[:]) {
-		err := fmt.Errorf("block %#x is not a descendant of the current finalized block slot %d, %#x != %#x",
+		err := fmt.Errorf("block %#x is not a descendent of the current finalized block slot %d, %#x != %#x",
 			bytesutil.Trunc(root[:]), finalizedBlk.Slot(), bytesutil.Trunc(bFinalizedRoot),
 			bytesutil.Trunc(fRoot[:]))
-		tracing.AnnotateError(span, err)
+		traceutil.AnnotateError(span, err)
 		return err
 	}
 	return nil
@@ -124,12 +121,8 @@ func (s *Service) VerifyBlkDescendant(ctx context.Context, root [32]byte) error

 // verifyBlkFinalizedSlot validates input block is not less than or equal
 // to current finalized slot.
-func (s *Service) verifyBlkFinalizedSlot(b block.BeaconBlock) error {
-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
-	finalizedSlot, err := slots.EpochStart(finalized.Epoch)
+func (s *Service) verifyBlkFinalizedSlot(b interfaces.BeaconBlock) error {
+	finalizedSlot, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
 	if err != nil {
 		return err
 	}
@@ -142,59 +135,63 @@ func (s *Service) verifyBlkFinalizedSlot(b block.BeaconBlock) error {
 // shouldUpdateCurrentJustified prevents bouncing attack, by only update conflicting justified
 // checkpoints in the fork choice if in the early slots of the epoch.
 // Otherwise, delay incorporation of new justified checkpoint until next epoch boundary.
-//
-// Spec code:
-// def should_update_justified_checkpoint(store: Store, new_justified_checkpoint: Checkpoint) -> bool:
-//    """
-//    To address the bouncing attack, only update conflicting justified
-//    checkpoints in the fork choice if in the early slots of the epoch.
-//    Otherwise, delay incorporation of new justified checkpoint until next epoch boundary.
-//
-//    See https://ethresear.ch/t/prevention-of-bouncing-attack-on-ffg/6114 for more detailed analysis and discussion.
-//    """
-//    if compute_slots_since_epoch_start(get_current_slot(store)) < SAFE_SLOTS_TO_UPDATE_JUSTIFIED:
-//        return True
-//
-//    justified_slot = compute_start_slot_at_epoch(store.justified_checkpoint.epoch)
-//    if not get_ancestor(store, new_justified_checkpoint.root, justified_slot) == store.justified_checkpoint.root:
-//        return False
-//
-//    return True
+// See https://ethresear.ch/t/prevention-of-bouncing-attack-on-ffg/6114 for more detailed analysis and discussion.
 func (s *Service) shouldUpdateCurrentJustified(ctx context.Context, newJustifiedCheckpt *ethpb.Checkpoint) (bool, error) {
-	ctx, span := trace.StartSpan(ctx, "blockChain.shouldUpdateCurrentJustified")
-	defer span.End()
-
-	if slots.SinceEpochStarts(s.CurrentSlot()) < params.BeaconConfig().SafeSlotsToUpdateJustified {
+	if helpers.SlotsSinceEpochStarts(s.CurrentSlot()) < params.BeaconConfig().SafeSlotsToUpdateJustified {
 		return true, nil
 	}
-	justified := s.store.JustifiedCheckpt()
-	jSlot, err := slots.EpochStart(justified.Epoch)
-	if err != nil {
-		return false, err
-	}
+	var newJustifiedBlockSigned interfaces.SignedBeaconBlock
 	justifiedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(newJustifiedCheckpt.Root))
-	b, err := s.ancestor(ctx, justifiedRoot[:], jSlot)
-	if err != nil {
-		return false, err
+	var err error
+	if s.hasInitSyncBlock(justifiedRoot) {
+		newJustifiedBlockSigned = s.getInitSyncBlock(justifiedRoot)
+	} else {
+		newJustifiedBlockSigned, err = s.cfg.BeaconDB.Block(ctx, justifiedRoot)
+		if err != nil {
+			return false, err
+		}
 	}
-	if !bytes.Equal(b, justified.Root) {
-		return false, nil
+	if newJustifiedBlockSigned == nil || newJustifiedBlockSigned.IsNil() || newJustifiedBlockSigned.Block().IsNil() {
+		return false, errors.New("nil new justified block")
 	}

+	newJustifiedBlock := newJustifiedBlockSigned.Block()
+	jSlot, err := helpers.StartSlot(s.justifiedCheckpt.Epoch)
+	if err != nil {
+		return false, err
+	}
+	if newJustifiedBlock.Slot() <= jSlot {
+		return false, nil
+	}
+	var justifiedBlockSigned interfaces.SignedBeaconBlock
+	cachedJustifiedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(s.justifiedCheckpt.Root))
+	if s.hasInitSyncBlock(cachedJustifiedRoot) {
+		justifiedBlockSigned = s.getInitSyncBlock(cachedJustifiedRoot)
+	} else {
+		justifiedBlockSigned, err = s.cfg.BeaconDB.Block(ctx, cachedJustifiedRoot)
+		if err != nil {
+			return false, err
+		}
+	}
+
+	if justifiedBlockSigned == nil || justifiedBlockSigned.IsNil() || justifiedBlockSigned.Block().IsNil() {
+		return false, errors.New("nil justified block")
+	}
+	justifiedBlock := justifiedBlockSigned.Block()
+	b, err := s.ancestor(ctx, justifiedRoot[:], justifiedBlock.Slot())
+	if err != nil {
+		return false, err
+	}
+	if !bytes.Equal(b, s.justifiedCheckpt.Root) {
+		return false, nil
+	}
 	return true, nil
 }

-func (s *Service) updateJustified(ctx context.Context, state state.ReadOnlyBeaconState) error {
-	ctx, span := trace.StartSpan(ctx, "blockChain.updateJustified")
-	defer span.End()
-
+func (s *Service) updateJustified(ctx context.Context, state iface.ReadOnlyBeaconState) error {
 	cpt := state.CurrentJustifiedCheckpoint()
-	bestJustified := s.store.BestJustifiedCheckpt()
-	if bestJustified == nil {
-		return errNilBestJustifiedInStore
-	}
-	if cpt.Epoch > bestJustified.Epoch {
-		s.store.SetBestJustifiedCheckpt(cpt)
+	if cpt.Epoch > s.bestJustifiedCheckpt.Epoch {
+		s.bestJustifiedCheckpt = cpt
 	}
 	canUpdate, err := s.shouldUpdateCurrentJustified(ctx, cpt)
 	if err != nil {
@@ -202,39 +199,30 @@ func (s *Service) updateJustified(ctx context.Context, state state.ReadOnlyBeaco
 	}

 	if canUpdate {
-		justified := s.store.JustifiedCheckpt()
-		if justified == nil {
-			return errNilJustifiedInStore
+		s.prevJustifiedCheckpt = s.justifiedCheckpt
+		s.justifiedCheckpt = cpt
+		if err := s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root)); err != nil {
+			return err
 		}
-		s.store.SetPrevJustifiedCheckpt(justified)
-		s.store.SetJustifiedCheckpt(cpt)
 	}

-	return nil
+	return s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, cpt)
 }

 // This caches input checkpoint as justified for the service struct. It rotates current justified to previous justified,
 // caches justified checkpoint balances for fork choice and save justified checkpoint in DB.
 // This method does not have defense against fork choice bouncing attack, which is why it's only recommend to be used during initial syncing.
 func (s *Service) updateJustifiedInitSync(ctx context.Context, cp *ethpb.Checkpoint) error {
-	justified := s.store.JustifiedCheckpt()
-	if justified == nil {
-		return errNilJustifiedInStore
-	}
-	s.store.SetPrevJustifiedCheckpt(justified)
-
-	if err := s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, cp); err != nil {
+	s.prevJustifiedCheckpt = s.justifiedCheckpt
+	s.justifiedCheckpt = cp
+	if err := s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root)); err != nil {
 		return err
 	}
-	s.store.SetJustifiedCheckpt(cp)

-	return nil
+	return s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, cp)
 }

 func (s *Service) updateFinalized(ctx context.Context, cp *ethpb.Checkpoint) error {
-	ctx, span := trace.StartSpan(ctx, "blockChain.updateFinalized")
-	defer span.End()
-
 	// Blocks need to be saved so that we can retrieve finalized block from
 	// DB when migrating states.
 	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
@@ -245,21 +233,16 @@ func (s *Service) updateFinalized(ctx context.Context, cp *ethpb.Checkpoint) err
 	if err := s.cfg.BeaconDB.SaveFinalizedCheckpoint(ctx, cp); err != nil {
 		return err
 	}
+	if !featureconfig.Get().UpdateHeadTimely {
+		s.prevFinalizedCheckpt = s.finalizedCheckpt
+		s.finalizedCheckpt = cp
+	}

 	fRoot := bytesutil.ToBytes32(cp.Root)
-	optimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(ctx, fRoot)
-	if err != nil {
-		return err
-	}
-	if !optimistic {
-		err = s.cfg.BeaconDB.SaveLastValidatedCheckpoint(ctx, cp)
-		if err != nil {
-			return err
-		}
-	}
 	if err := s.cfg.StateGen.MigrateToCold(ctx, fRoot); err != nil {
 		return errors.Wrap(err, "could not migrate to cold")
 	}
+
 	return nil
 }

@@ -336,21 +319,60 @@ func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot types.Slot)
 	return s.ancestorByDB(ctx, bytesutil.ToBytes32(b.ParentRoot()), slot)
 }

+// This updates justified check point in store, if the new justified is later than stored justified or
+// the store's justified is not in chain with finalized check point.
+//
+// Spec definition:
+//   # Potentially update justified if different from store
+//        if store.justified_checkpoint != state.current_justified_checkpoint:
+//            # Update justified if new justified is later than store justified
+//            if state.current_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
+//                store.justified_checkpoint = state.current_justified_checkpoint
+//                return
+//            # Update justified if store justified is not in chain with finalized checkpoint
+//            finalized_slot = compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
+//            ancestor_at_finalized_slot = get_ancestor(store, store.justified_checkpoint.root, finalized_slot)
+//            if ancestor_at_finalized_slot != store.finalized_checkpoint.root:
+//                store.justified_checkpoint = state.current_justified_checkpoint
+func (s *Service) finalizedImpliesNewJustified(ctx context.Context, state iface.BeaconState) error {
+	// Update justified if it's different than the one cached in the store.
+	if !attestationutil.CheckPointIsEqual(s.justifiedCheckpt, state.CurrentJustifiedCheckpoint()) {
+		if state.CurrentJustifiedCheckpoint().Epoch > s.justifiedCheckpt.Epoch {
+			s.justifiedCheckpt = state.CurrentJustifiedCheckpoint()
+			return s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root))
+		}
+
+		// Update justified if store justified is not in chain with finalized check point.
+		finalizedSlot, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+		if err != nil {
+			return err
+		}
+		justifiedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(s.justifiedCheckpt.Root))
+		anc, err := s.ancestor(ctx, justifiedRoot[:], finalizedSlot)
+		if err != nil {
+			return err
+		}
+		if !bytes.Equal(anc, s.finalizedCheckpt.Root) {
+			s.justifiedCheckpt = state.CurrentJustifiedCheckpoint()
+			if err := s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root)); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
 // This retrieves missing blocks from DB (ie. the blocks that couldn't be received over sync) and inserts them to fork choice store.
 // This is useful for block tree visualizer and additional vote accounting.
-func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk block.BeaconBlock,
+func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk interfaces.BeaconBlock,
 	fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
-	pendingNodes := make([]block.BeaconBlock, 0)
+	pendingNodes := make([]interfaces.BeaconBlock, 0)
 	pendingRoots := make([][32]byte, 0)

 	parentRoot := bytesutil.ToBytes32(blk.ParentRoot())
 	slot := blk.Slot()
 	// Fork choice only matters from last finalized slot.
-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
-	fSlot, err := slots.EpochStart(finalized.Epoch)
+	fSlot, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
 	if err != nil {
 		return err
 	}
@@ -375,17 +397,14 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk block.B
 	for i := len(pendingNodes) - 1; i >= 0; i-- {
 		b := pendingNodes[i]
 		r := pendingRoots[i]
-		payloadHash, err := getBlockPayloadHash(blk)
-		if err != nil {
-			return err
-		}
-		if err := s.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx,
-			b.Slot(), r, bytesutil.ToBytes32(b.ParentRoot()), payloadHash,
+		if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
+			b.Slot(), r, bytesutil.ToBytes32(b.ParentRoot()), bytesutil.ToBytes32(b.Body().Graffiti()),
 			jCheckpoint.Epoch,
 			fCheckpoint.Epoch); err != nil {
 			return errors.Wrap(err, "could not process block for proto array fork choice")
 		}
 	}
+
 	return nil
 }

@@ -432,7 +451,7 @@ func (s *Service) deletePoolAtts(atts []*ethpb.Attestation) error {
 // fork choice justification routine.
 func (s *Service) ensureRootNotZeros(root [32]byte) [32]byte {
 	if root == params.BeaconConfig().ZeroHash {
-		return s.originBlockRoot
+		return s.genesisRoot
 	}
 	return root
 }
--- a/beacon-chain/blockchain/process_block_test.go
+++ b/beacon-chain/blockchain/process_block_test.go
--- a/beacon-chain/blockchain/receive_attestation.go
+++ b/beacon-chain/blockchain/receive_attestation.go
@@ -7,28 +7,21 @@ import (
 	"time"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/async/event"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/slotutil"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

-// AttestationStateFetcher allows for retrieving a beacon state corresponding to the block
-// root of an attestation's target checkpoint.
-type AttestationStateFetcher interface {
-	AttestationTargetState(ctx context.Context, target *ethpb.Checkpoint) (state.BeaconState, error)
-}
-
 // AttestationReceiver interface defines the methods of chain service receive and processing new attestations.
 type AttestationReceiver interface {
-	AttestationStateFetcher
 	ReceiveAttestationNoPubsub(ctx context.Context, att *ethpb.Attestation) error
+	AttestationPreState(ctx context.Context, att *ethpb.Attestation) (iface.BeaconState, error)
 	VerifyLmdFfgConsistency(ctx context.Context, att *ethpb.Attestation) error
 	VerifyFinalizedConsistency(ctx context.Context, root []byte) error
 }
@@ -42,28 +35,28 @@ func (s *Service) ReceiveAttestationNoPubsub(ctx context.Context, att *ethpb.Att
 	ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.ReceiveAttestationNoPubsub")
 	defer span.End()

-	if err := s.OnAttestation(ctx, att); err != nil {
+	if err := s.onAttestation(ctx, att); err != nil {
 		return errors.Wrap(err, "could not process attestation")
 	}

 	return nil
 }

-// AttestationTargetState returns the pre state of attestation.
-func (s *Service) AttestationTargetState(ctx context.Context, target *ethpb.Checkpoint) (state.BeaconState, error) {
-	ss, err := slots.EpochStart(target.Epoch)
+// AttestationPreState returns the pre state of attestation.
+func (s *Service) AttestationPreState(ctx context.Context, att *ethpb.Attestation) (iface.BeaconState, error) {
+	ss, err := helpers.StartSlot(att.Data.Target.Epoch)
 	if err != nil {
 		return nil, err
 	}
-	if err := slots.ValidateClock(ss, uint64(s.genesisTime.Unix())); err != nil {
+	if err := helpers.ValidateSlotClock(ss, uint64(s.genesisTime.Unix())); err != nil {
 		return nil, err
 	}
-	return s.getAttPreState(ctx, target)
+	return s.getAttPreState(ctx, att.Data.Target)
 }

 // VerifyLmdFfgConsistency verifies that attestation's LMD and FFG votes are consistency to each other.
 func (s *Service) VerifyLmdFfgConsistency(ctx context.Context, a *ethpb.Attestation) error {
-	targetSlot, err := slots.EpochStart(a.Data.Target.Epoch)
+	targetSlot, err := helpers.StartSlot(a.Data.Target.Epoch)
 	if err != nil {
 		return err
 	}
@@ -88,10 +81,7 @@ func (s *Service) VerifyFinalizedConsistency(ctx context.Context, root []byte) e
 	}

 	f := s.FinalizedCheckpt()
-	if f == nil {
-		return errNilFinalizedInStore
-	}
-	ss, err := slots.EpochStart(f.Epoch)
+	ss, err := helpers.StartSlot(f.Epoch)
 	if err != nil {
 		return err
 	}
@@ -107,90 +97,38 @@ func (s *Service) VerifyFinalizedConsistency(ctx context.Context, root []byte) e
 }

 // This routine processes fork choice attestations from the pool to account for validator votes and fork choice.
-func (s *Service) spawnProcessAttestationsRoutine(stateFeed *event.Feed) {
+func (s *Service) processAttestationsRoutine(subscribedToStateEvents chan<- struct{}) {
 	// Wait for state to be initialized.
 	stateChannel := make(chan *feed.Event, 1)
-	stateSub := stateFeed.Subscribe(stateChannel)
-	go func() {
+	stateSub := s.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
+	subscribedToStateEvents <- struct{}{}
+	<-stateChannel
+	stateSub.Unsubscribe()
+
+	if s.genesisTime.IsZero() {
+		log.Warn("ProcessAttestations routine waiting for genesis time")
+		for s.genesisTime.IsZero() {
+			time.Sleep(1 * time.Second)
+		}
+		log.Warn("Genesis time received, now available to process attestations")
+	}
+
+	st := slotutil.NewSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
+	for {
 		select {
 		case <-s.ctx.Done():
-			stateSub.Unsubscribe()
 			return
-		case <-stateChannel:
-			stateSub.Unsubscribe()
-			break
-		}
-
-		if s.genesisTime.IsZero() {
-			log.Warn("ProcessAttestations routine waiting for genesis time")
-			for s.genesisTime.IsZero() {
-				if err := s.ctx.Err(); err != nil {
-					log.WithError(err).Error("Giving up waiting for genesis time")
-					return
-				}
-				time.Sleep(1 * time.Second)
+		case <-st.C():
+			// Continue when there's no fork choice attestation, there's nothing to process and update head.
+			// This covers the condition when the node is still initial syncing to the head of the chain.
+			if s.cfg.AttPool.ForkchoiceAttestationCount() == 0 {
+				continue
 			}
-			log.Warn("Genesis time received, now available to process attestations")
-		}
-
-		st := slots.NewSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
-		for {
-			select {
-			case <-s.ctx.Done():
-				return
-			case <-st.C():
-				if err := s.NewSlot(s.ctx, s.CurrentSlot()); err != nil {
-					log.WithError(err).Error("Could not process new slot")
-					return
-				}
-
-				// Continue when there's no fork choice attestation, there's nothing to process and update head.
-				// This covers the condition when the node is still initial syncing to the head of the chain.
-				if s.cfg.AttPool.ForkchoiceAttestationCount() == 0 {
-					continue
-				}
-				s.processAttestations(s.ctx)
-
-				justified := s.store.JustifiedCheckpt()
-				if justified == nil {
-					log.WithError(errNilJustifiedInStore).Error("Could not get justified checkpoint")
-					continue
-				}
-				balances, err := s.justifiedBalances.get(s.ctx, bytesutil.ToBytes32(justified.Root))
-				if err != nil {
-					log.WithError(err).Errorf("Unable to get justified balances for root %v", justified.Root)
-					continue
-				}
-				newHeadRoot, err := s.updateHead(s.ctx, balances)
-				if err != nil {
-					log.WithError(err).Warn("Resolving fork due to new attestation")
-				}
-				s.notifyEngineIfChangedHead(s.ctx, newHeadRoot)
+			s.processAttestations(s.ctx)
+			if err := s.updateHead(s.ctx, s.getJustifiedBalances()); err != nil {
+				log.Warnf("Resolving fork due to new attestation: %v", err)
 			}
 		}
-	}()
-}
-
-// This calls notify Forkchoice Update in the event that the head has changed
-func (s *Service) notifyEngineIfChangedHead(ctx context.Context, newHeadRoot [32]byte) {
-	if s.headRoot() == newHeadRoot {
-		return
-	}
-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		log.WithError(errNilFinalizedInStore).Error("could not get finalized checkpoint")
-		return
-	}
-	_, err := s.notifyForkchoiceUpdate(s.ctx,
-		s.headBlock().Block(),
-		s.headRoot(),
-		bytesutil.ToBytes32(finalized.Root),
-	)
-	if err != nil {
-		log.WithError(err).Error("could not notify forkchoice update")
-	}
-	if err := s.saveHead(ctx, newHeadRoot); err != nil {
-		log.WithError(err).Error("could not save head")
 	}
 }

@@ -200,9 +138,9 @@ func (s *Service) processAttestations(ctx context.Context) {
 	for _, a := range atts {
 		// Based on the spec, don't process the attestation until the subsequent slot.
 		// This delays consideration in the fork choice until their slot is in the past.
-		// https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/fork-choice.md#validate_on_attestation
+		// https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/fork-choice.md#validate_on_attestation
 		nextSlot := a.Data.Slot + 1
-		if err := slots.VerifyTime(uint64(s.genesisTime.Unix()), nextSlot, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
+		if err := helpers.VerifySlotTime(uint64(s.genesisTime.Unix()), nextSlot, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
 			continue
 		}

--- a/beacon-chain/blockchain/receive_attestation_test.go
+++ b/beacon-chain/blockchain/receive_attestation_test.go
@@ -7,25 +7,21 @@ import (

 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	prysmTime "github.com/prysmaticlabs/prysm/time"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

-var (
-	_ = AttestationReceiver(&Service{})
-	_ = AttestationStateFetcher(&Service{})
-)
-
 func TestAttestationCheckPtState_FarFutureSlot(t *testing.T) {
 	helpers.ClearCache()
 	beaconDB := testDB.SetupDB(t)
@@ -33,36 +29,33 @@ func TestAttestationCheckPtState_FarFutureSlot(t *testing.T) {
 	chainService := setupBeaconChain(t, beaconDB)
 	chainService.genesisTime = time.Now()

-	e := types.Epoch(slots.MaxSlotBuffer/uint64(params.BeaconConfig().SlotsPerEpoch) + 1)
-	_, err := chainService.AttestationTargetState(context.Background(), &ethpb.Checkpoint{Epoch: e})
+	e := types.Epoch(helpers.MaxSlotBuffer/uint64(params.BeaconConfig().SlotsPerEpoch) + 1)
+	_, err := chainService.AttestationPreState(context.Background(), &ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Epoch: e}}})
 	require.ErrorContains(t, "exceeds max allowed value relative to the local clock", err)
 }

 func TestVerifyLMDFFGConsistent_NotOK(t *testing.T) {
 	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
+	beaconDB := testDB.SetupDB(t)

-	service, err := NewService(ctx, opts...)
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	b32 := util.NewBeaconBlock()
+	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b32)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b32)))
 	r32, err := b32.Block.HashTreeRoot()
 	require.NoError(t, err)
-	b33 := util.NewBeaconBlock()
+	b33 := testutil.NewBeaconBlock()
 	b33.Block.Slot = 33
 	b33.Block.ParentRoot = r32[:]
-	wsb, err = wrapper.WrappedSignedBeaconBlock(b33)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b33)))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

 	wanted := "FFG and LMD votes are not consistent"
-	a := util.NewAttestation()
+	a := testutil.NewAttestation()
 	a.Data.Target.Epoch = 1
 	a.Data.Target.Root = []byte{'a'}
 	a.Data.BeaconBlockRoot = r33[:]
@@ -71,28 +64,25 @@ func TestVerifyLMDFFGConsistent_NotOK(t *testing.T) {

 func TestVerifyLMDFFGConsistent_OK(t *testing.T) {
 	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)

-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	b32 := util.NewBeaconBlock()
+	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b32)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b32)))
 	r32, err := b32.Block.HashTreeRoot()
 	require.NoError(t, err)
-	b33 := util.NewBeaconBlock()
+	b33 := testutil.NewBeaconBlock()
 	b33.Block.Slot = 33
 	b33.Block.ParentRoot = r32[:]
-	wsb, err = wrapper.WrappedSignedBeaconBlock(b33)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b33)))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

-	a := util.NewAttestation()
+	a := testutil.NewAttestation()
 	a.Data.Target.Epoch = 1
 	a.Data.Target.Root = r32[:]
 	a.Data.BeaconBlockRoot = r33[:]
@@ -103,61 +93,30 @@ func TestVerifyLMDFFGConsistent_OK(t *testing.T) {
 func TestProcessAttestations_Ok(t *testing.T) {
 	hook := logTest.NewGlobal()
 	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
-	opts = append(opts, WithAttestationPool(attestations.NewPool()))
+	beaconDB := testDB.SetupDB(t)

-	service, err := NewService(ctx, opts...)
+	cfg := &Config{
+		BeaconDB:        beaconDB,
+		ForkChoiceStore: protoarray.New(0, 0, [32]byte{}),
+		StateGen:        stategen.New(beaconDB),
+		AttPool:         attestations.NewPool(),
+	}
+	service, err := NewService(ctx, cfg)
+	service.genesisTime = timeutils.Now().Add(-1 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)
 	require.NoError(t, err)
-	service.genesisTime = prysmTime.Now().Add(-1 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)
-	genesisState, pks := util.DeterministicGenesisState(t, 64)
-	require.NoError(t, genesisState.SetGenesisTime(uint64(prysmTime.Now().Unix())-params.BeaconConfig().SecondsPerSlot))
+	genesisState, pks := testutil.DeterministicGenesisState(t, 64)
+	require.NoError(t, genesisState.SetGenesisTime(uint64(timeutils.Now().Unix())-params.BeaconConfig().SecondsPerSlot))
 	require.NoError(t, service.saveGenesisData(ctx, genesisState))
-	atts, err := util.GenerateAttestations(genesisState, pks, 1, 0, false)
+	atts, err := testutil.GenerateAttestations(genesisState, pks, 1, 0, false)
 	require.NoError(t, err)
 	tRoot := bytesutil.ToBytes32(atts[0].Data.Target.Root)
 	copied := genesisState.Copy()
-	copied, err = transition.ProcessSlots(ctx, copied, 1)
+	copied, err = state.ProcessSlots(ctx, copied, 1)
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
-	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 0, tRoot, tRoot, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
 	require.NoError(t, service.cfg.AttPool.SaveForkchoiceAttestations(atts))
 	service.processAttestations(ctx)
 	require.Equal(t, 0, len(service.cfg.AttPool.ForkchoiceAttestations()))
 	require.LogsDoNotContain(t, hook, "Could not process attestation for fork choice")
 }
-
-func TestNotifyEngineIfChangedHead(t *testing.T) {
-	hook := logTest.NewGlobal()
-	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	service.notifyEngineIfChangedHead(ctx, service.headRoot())
-	hookErr := "could not notify forkchoice update"
-	finalizedErr := "could not get finalized checkpoint"
-	require.LogsDoNotContain(t, hook, finalizedErr)
-	require.LogsDoNotContain(t, hook, hookErr)
-	service.notifyEngineIfChangedHead(ctx, [32]byte{'a'})
-	require.LogsContain(t, hook, finalizedErr)
-
-	hook.Reset()
-	b := util.NewBeaconBlock()
-	b.Block.Slot = 1
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
-	r, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	finalized := &ethpb.Checkpoint{Root: r[:], Epoch: 0}
-	service.head = &head{
-		slot:  1,
-		root:  r,
-		block: wsb,
-	}
-	service.store.SetFinalizedCheckpt(finalized)
-	service.notifyEngineIfChangedHead(ctx, [32]byte{'b'})
-	require.LogsDoNotContain(t, hook, finalizedErr)
-	require.LogsDoNotContain(t, hook, hookErr)
-}
--- a/beacon-chain/blockchain/receive_block.go
+++ b/beacon-chain/blockchain/receive_block.go
@@ -7,10 +7,11 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
-	"github.com/prysmaticlabs/prysm/monitoring/tracing"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/time"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
+	"github.com/prysmaticlabs/prysm/shared/traceutil"
 	"go.opencensus.io/trace"
 )

@@ -19,8 +20,8 @@ var epochsSinceFinalitySaveHotStateDB = types.Epoch(100)

 // BlockReceiver interface defines the methods of chain service receive and processing new blocks.
 type BlockReceiver interface {
-	ReceiveBlock(ctx context.Context, block block.SignedBeaconBlock, blockRoot [32]byte) error
-	ReceiveBlockBatch(ctx context.Context, blocks []block.SignedBeaconBlock, blkRoots [][32]byte) error
+	ReceiveBlock(ctx context.Context, block interfaces.SignedBeaconBlock, blockRoot [32]byte) error
+	ReceiveBlockBatch(ctx context.Context, blocks []interfaces.SignedBeaconBlock, blkRoots [][32]byte) error
 	HasInitSyncBlock(root [32]byte) bool
 }

@@ -29,19 +30,36 @@ type BlockReceiver interface {
 //   1. Validate block, apply state transition and update check points
 //   2. Apply fork choice to the processed block
 //   3. Save latest head info
-func (s *Service) ReceiveBlock(ctx context.Context, block block.SignedBeaconBlock, blockRoot [32]byte) error {
+func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.SignedBeaconBlock, blockRoot [32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlock")
 	defer span.End()
-	receivedTime := time.Now()
+	receivedTime := timeutils.Now()
 	blockCopy := block.Copy()

 	// Apply state transition on the new block.
 	if err := s.onBlock(ctx, blockCopy, blockRoot); err != nil {
 		err := errors.Wrap(err, "could not process block")
-		tracing.AnnotateError(span, err)
+		traceutil.AnnotateError(span, err)
 		return err
 	}

+	// Update and save head block after fork choice.
+	if !featureconfig.Get().UpdateHeadTimely {
+		if err := s.updateHead(ctx, s.getJustifiedBalances()); err != nil {
+			log.WithError(err).Warn("Could not update head")
+		}
+		// Send notification of the processed block to the state feed.
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+			Type: statefeed.BlockProcessed,
+			Data: &statefeed.BlockProcessedData{
+				Slot:        blockCopy.Block().Slot(),
+				BlockRoot:   blockRoot,
+				SignedBlock: blockCopy,
+				Verified:    true,
+			},
+		})
+	}
+
 	// Handle post block operations such as attestations and exits.
 	if err := s.handlePostBlockOperations(blockCopy.Block()); err != nil {
 		return err
@@ -53,20 +71,14 @@ func (s *Service) ReceiveBlock(ctx context.Context, block block.SignedBeaconBloc
 	}

 	// Reports on block and fork choice metrics.
-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
-	reportSlotMetrics(blockCopy.Block().Slot(), s.HeadSlot(), s.CurrentSlot(), finalized)
+	reportSlotMetrics(blockCopy.Block().Slot(), s.HeadSlot(), s.CurrentSlot(), s.finalizedCheckpt)

 	// Log block sync status.
-	if err := logBlockSyncStatus(blockCopy.Block(), blockRoot, finalized, receivedTime, uint64(s.genesisTime.Unix())); err != nil {
+	if err := logBlockSyncStatus(blockCopy.Block(), blockRoot, s.finalizedCheckpt, receivedTime, uint64(s.genesisTime.Unix())); err != nil {
 		return err
 	}
 	// Log state transition data.
-	if err := logStateTransitionData(blockCopy.Block()); err != nil {
-		return err
-	}
+	logStateTransitionData(blockCopy.Block())

 	return nil
 }
@@ -74,7 +86,7 @@ func (s *Service) ReceiveBlock(ctx context.Context, block block.SignedBeaconBloc
 // ReceiveBlockBatch processes the whole block batch at once, assuming the block batch is linear ,transitioning
 // the state, performing batch verification of all collected signatures and then performing the appropriate
 // actions for a block post-transition.
-func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []block.SignedBeaconBlock, blkRoots [][32]byte) error {
+func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []interfaces.SignedBeaconBlock, blkRoots [][32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlockBatch")
 	defer span.End()

@@ -82,14 +94,14 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []block.SignedBe
 	fCheckpoints, jCheckpoints, err := s.onBlockBatch(ctx, blocks, blkRoots)
 	if err != nil {
 		err := errors.Wrap(err, "could not process block in batch")
-		tracing.AnnotateError(span, err)
+		traceutil.AnnotateError(span, err)
 		return err
 	}

 	for i, b := range blocks {
 		blockCopy := b.Copy()
 		if err = s.handleBlockAfterBatchVerify(ctx, blockCopy, blkRoots[i], fCheckpoints[i], jCheckpoints[i]); err != nil {
-			tracing.AnnotateError(span, err)
+			traceutil.AnnotateError(span, err)
 			return err
 		}
 		// Send notification of the processed block to the state feed.
@@ -104,21 +116,10 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []block.SignedBe
 		})

 		// Reports on blockCopy and fork choice metrics.
-		finalized := s.store.FinalizedCheckpt()
-		if finalized == nil {
-			return errNilFinalizedInStore
-		}
-		reportSlotMetrics(blockCopy.Block().Slot(), s.HeadSlot(), s.CurrentSlot(), finalized)
+		reportSlotMetrics(blockCopy.Block().Slot(), s.HeadSlot(), s.CurrentSlot(), s.finalizedCheckpt)
 	}

-	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
-		return err
-	}
-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
-	if err := s.wsVerifier.VerifyWeakSubjectivity(s.ctx, finalized.Epoch); err != nil {
+	if err := s.VerifyWeakSubjectivityRoot(s.ctx); err != nil {
 		// log.Fatalf will prevent defer from being called
 		span.End()
 		// Exit run time if the node failed to verify weak subjectivity checkpoint.
@@ -133,7 +134,7 @@ func (s *Service) HasInitSyncBlock(root [32]byte) bool {
 	return s.hasInitSyncBlock(root)
 }

-func (s *Service) handlePostBlockOperations(b block.BeaconBlock) error {
+func (s *Service) handlePostBlockOperations(b interfaces.BeaconBlock) error {
 	// Delete the processed block attestations from attestation pool.
 	if err := s.deletePoolAtts(b.Body().Attestations()); err != nil {
 		return err
@@ -159,15 +160,11 @@ func (s *Service) handlePostBlockOperations(b block.BeaconBlock) error {
 // This checks whether it's time to start saving hot state to DB.
 // It's time when there's `epochsSinceFinalitySaveHotStateDB` epochs of non-finality.
 func (s *Service) checkSaveHotStateDB(ctx context.Context) error {
-	currentEpoch := slots.ToEpoch(s.CurrentSlot())
+	currentEpoch := helpers.SlotToEpoch(s.CurrentSlot())
 	// Prevent `sinceFinality` going underflow.
 	var sinceFinality types.Epoch
-	finalized := s.store.FinalizedCheckpt()
-	if finalized == nil {
-		return errNilFinalizedInStore
-	}
-	if currentEpoch > finalized.Epoch {
-		sinceFinality = currentEpoch - finalized.Epoch
+	if currentEpoch > s.finalizedCheckpt.Epoch {
+		sinceFinality = currentEpoch - s.finalizedCheckpt.Epoch
 	}

 	if sinceFinality >= epochsSinceFinalitySaveHotStateDB {
--- a/beacon-chain/blockchain/receive_block_test.go
+++ b/beacon-chain/blockchain/receive_block_test.go
@@ -13,27 +13,25 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

 func TestService_ReceiveBlock(t *testing.T) {
 	ctx := context.Background()

-	genesis, keys := util.DeterministicGenesisState(t, 64)
-	genFullBlock := func(t *testing.T, conf *util.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
-		blk, err := util.GenerateFullBlock(genesis, keys, conf, slot)
+	genesis, keys := testutil.DeterministicGenesisState(t, 64)
+	genFullBlock := func(t *testing.T, conf *testutil.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
+		blk, err := testutil.GenerateFullBlock(genesis, keys, conf, slot)
 		assert.NoError(t, err)
 		return blk
 	}
-	params.SetupTestConfigCleanup(t)
 	bc := params.BeaconConfig()
 	bc.ShardCommitteePeriod = 0 // Required for voluntary exits test in reasonable time.
 	params.OverrideBeaconConfig(bc)
@@ -50,7 +48,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 		{
 			name: "applies block with state transition",
 			args: args{
-				block: genFullBlock(t, util.DefaultBlockGenConfig(), 2 /*slot*/),
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 2 /*slot*/),
 			},
 			check: func(t *testing.T, s *Service) {
 				if hs := s.head.state.Slot(); hs != 2 {
@@ -65,7 +63,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 			name: "saves attestations to pool",
 			args: args{
 				block: genFullBlock(t,
-					&util.BlockGenConfig{
+					&testutil.BlockGenConfig{
 						NumProposerSlashings: 0,
 						NumAttesterSlashings: 0,
 						NumAttestations:      2,
@@ -85,7 +83,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 		{
 			name: "updates exit pool",
 			args: args{
-				block: genFullBlock(t, &util.BlockGenConfig{
+				block: genFullBlock(t, &testutil.BlockGenConfig{
 					NumProposerSlashings: 0,
 					NumAttesterSlashings: 0,
 					NumAttestations:      0,
@@ -109,7 +107,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 		{
 			name: "notifies block processed on state feed",
 			args: args{
-				block: genFullBlock(t, util.DefaultBlockGenConfig(), 1 /*slot*/),
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 1 /*slot*/),
 			},
 			check: func(t *testing.T, s *Service) {
 				if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
@@ -125,28 +123,29 @@ func TestService_ReceiveBlock(t *testing.T) {
 			genesisBlockRoot := bytesutil.ToBytes32(nil)
 			require.NoError(t, beaconDB.SaveState(ctx, genesis, genesisBlockRoot))

-			opts := []Option{
-				WithDatabase(beaconDB),
-				WithForkChoiceStore(protoarray.New(0, 0, genesisBlockRoot)),
-				WithAttestationPool(attestations.NewPool()),
-				WithExitPool(voluntaryexits.NewPool()),
-				WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}),
-				WithStateGen(stategen.New(beaconDB)),
-				WithFinalizedStateAtStartUp(genesis),
+			cfg := &Config{
+				BeaconDB: beaconDB,
+				ForkChoiceStore: protoarray.New(
+					0, // justifiedEpoch
+					0, // finalizedEpoch
+					genesisBlockRoot,
+				),
+				AttPool:       attestations.NewPool(),
+				ExitPool:      voluntaryexits.NewPool(),
+				StateNotifier: &blockchainTesting.MockStateNotifier{RecordEvents: true},
+				StateGen:      stategen.New(beaconDB),
 			}
-			s, err := NewService(ctx, opts...)
+			s, err := NewService(ctx, cfg)
 			require.NoError(t, err)
 			require.NoError(t, s.saveGenesisData(ctx, genesis))
 			gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
 			require.NoError(t, err)
 			gRoot, err := gBlk.Block().HashTreeRoot()
 			require.NoError(t, err)
-			s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: gRoot[:]})
+			s.finalizedCheckpt = &ethpb.Checkpoint{Root: gRoot[:]}
 			root, err := tt.args.block.Block.HashTreeRoot()
 			require.NoError(t, err)
-			wsb, err := wrapper.WrappedSignedBeaconBlock(tt.args.block)
-			require.NoError(t, err)
-			err = s.ReceiveBlock(ctx, wsb, root)
+			err = s.ReceiveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(tt.args.block), root)
 			if tt.wantedErr != "" {
 				assert.ErrorContains(t, tt.wantedErr, err)
 			} else {
@@ -159,37 +158,38 @@ func TestService_ReceiveBlock(t *testing.T) {

 func TestService_ReceiveBlockUpdateHead(t *testing.T) {
 	ctx := context.Background()
-	genesis, keys := util.DeterministicGenesisState(t, 64)
-	b, err := util.GenerateFullBlock(genesis, keys, util.DefaultBlockGenConfig(), 1)
+	genesis, keys := testutil.DeterministicGenesisState(t, 64)
+	b, err := testutil.GenerateFullBlock(genesis, keys, testutil.DefaultBlockGenConfig(), 1)
 	assert.NoError(t, err)
 	beaconDB := testDB.SetupDB(t)
 	genesisBlockRoot := bytesutil.ToBytes32(nil)
 	require.NoError(t, beaconDB.SaveState(ctx, genesis, genesisBlockRoot))
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(protoarray.New(0, 0, genesisBlockRoot)),
-		WithAttestationPool(attestations.NewPool()),
-		WithExitPool(voluntaryexits.NewPool()),
-		WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}),
-		WithStateGen(stategen.New(beaconDB)),
+	cfg := &Config{
+		BeaconDB: beaconDB,
+		ForkChoiceStore: protoarray.New(
+			0, // justifiedEpoch
+			0, // finalizedEpoch
+			genesisBlockRoot,
+		),
+		AttPool:       attestations.NewPool(),
+		ExitPool:      voluntaryexits.NewPool(),
+		StateNotifier: &blockchainTesting.MockStateNotifier{RecordEvents: true},
+		StateGen:      stategen.New(beaconDB),
 	}
-
-	s, err := NewService(ctx, opts...)
+	s, err := NewService(ctx, cfg)
 	require.NoError(t, err)
 	require.NoError(t, s.saveGenesisData(ctx, genesis))
 	gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
 	require.NoError(t, err)
 	gRoot, err := gBlk.Block().HashTreeRoot()
 	require.NoError(t, err)
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: gRoot[:]})
+	s.finalizedCheckpt = &ethpb.Checkpoint{Root: gRoot[:]}
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
 	wg := sync.WaitGroup{}
 	wg.Add(1)
 	go func() {
-		wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-		require.NoError(t, err)
-		require.NoError(t, s.ReceiveBlock(ctx, wsb, root))
+		require.NoError(t, s.ReceiveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(b), root))
 		wg.Done()
 	}()
 	wg.Wait()
@@ -197,15 +197,15 @@ func TestService_ReceiveBlockUpdateHead(t *testing.T) {
 		t.Errorf("Received %d state notifications, expected at least 1", recvd)
 	}
 	// Verify fork choice has processed the block. (Genesis block and the new block)
-	assert.Equal(t, 2, s.cfg.ForkChoiceStore.NodeCount())
+	assert.Equal(t, 2, len(s.cfg.ForkChoiceStore.Nodes()))
 }

 func TestService_ReceiveBlockBatch(t *testing.T) {
 	ctx := context.Background()

-	genesis, keys := util.DeterministicGenesisState(t, 64)
-	genFullBlock := func(t *testing.T, conf *util.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
-		blk, err := util.GenerateFullBlock(genesis, keys, conf, slot)
+	genesis, keys := testutil.DeterministicGenesisState(t, 64)
+	genFullBlock := func(t *testing.T, conf *testutil.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
+		blk, err := testutil.GenerateFullBlock(genesis, keys, conf, slot)
 		assert.NoError(t, err)
 		return blk
 	}
@@ -222,7 +222,7 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 		{
 			name: "applies block with state transition",
 			args: args{
-				block: genFullBlock(t, util.DefaultBlockGenConfig(), 2 /*slot*/),
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 2 /*slot*/),
 			},
 			check: func(t *testing.T, s *Service) {
 				assert.Equal(t, types.Slot(2), s.head.state.Slot(), "Incorrect head state slot")
@@ -232,7 +232,7 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 		{
 			name: "notifies block processed on state feed",
 			args: args{
-				block: genFullBlock(t, util.DefaultBlockGenConfig(), 1 /*slot*/),
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 1 /*slot*/),
 			},
 			check: func(t *testing.T, s *Service) {
 				if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
@@ -247,13 +247,17 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 			beaconDB := testDB.SetupDB(t)
 			genesisBlockRoot, err := genesis.HashTreeRoot(ctx)
 			require.NoError(t, err)
-			opts := []Option{
-				WithDatabase(beaconDB),
-				WithForkChoiceStore(protoarray.New(0, 0, genesisBlockRoot)),
-				WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}),
-				WithStateGen(stategen.New(beaconDB)),
+			cfg := &Config{
+				BeaconDB: beaconDB,
+				ForkChoiceStore: protoarray.New(
+					0, // justifiedEpoch
+					0, // finalizedEpoch
+					genesisBlockRoot,
+				),
+				StateNotifier: &blockchainTesting.MockStateNotifier{RecordEvents: true},
+				StateGen:      stategen.New(beaconDB),
 			}
-			s, err := NewService(ctx, opts...)
+			s, err := NewService(ctx, cfg)
 			require.NoError(t, err)
 			err = s.saveGenesisData(ctx, genesis)
 			require.NoError(t, err)
@@ -262,12 +266,10 @@ func TestService_ReceiveBlockBatch(t *testing.T) {

 			gRoot, err := gBlk.Block().HashTreeRoot()
 			require.NoError(t, err)
-			s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: gRoot[:]})
+			s.finalizedCheckpt = &ethpb.Checkpoint{Root: gRoot[:]}
 			root, err := tt.args.block.Block.HashTreeRoot()
 			require.NoError(t, err)
-			wsb, err := wrapper.WrappedSignedBeaconBlock(tt.args.block)
-			require.NoError(t, err)
-			blks := []block.SignedBeaconBlock{wsb}
+			blks := []interfaces.SignedBeaconBlock{interfaces.WrappedPhase0SignedBeaconBlock(tt.args.block)}
 			roots := [][32]byte{root}
 			err = s.ReceiveBlockBatch(ctx, blks, roots)
 			if tt.wantedErr != "" {
@@ -281,41 +283,37 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 }

 func TestService_HasInitSyncBlock(t *testing.T) {
-	opts := testServiceOptsNoDB()
-	opts = append(opts, WithStateNotifier(&blockchainTesting.MockStateNotifier{}))
-	s, err := NewService(context.Background(), opts...)
+	s, err := NewService(context.Background(), &Config{StateNotifier: &blockchainTesting.MockStateNotifier{}})
 	require.NoError(t, err)
 	r := [32]byte{'a'}
 	if s.HasInitSyncBlock(r) {
 		t.Error("Should not have block")
 	}
-	wsb, err := wrapper.WrappedSignedBeaconBlock(util.NewBeaconBlock())
-	require.NoError(t, err)
-	s.saveInitSyncBlock(r, wsb)
+	s.saveInitSyncBlock(r, interfaces.WrappedPhase0SignedBeaconBlock(testutil.NewBeaconBlock()))
 	if !s.HasInitSyncBlock(r) {
 		t.Error("Should have block")
 	}
 }

 func TestCheckSaveHotStateDB_Enabling(t *testing.T) {
-	opts := testServiceOptsWithDB(t)
+	beaconDB := testDB.SetupDB(t)
 	hook := logTest.NewGlobal()
-	s, err := NewService(context.Background(), opts...)
+	s, err := NewService(context.Background(), &Config{StateGen: stategen.New(beaconDB)})
 	require.NoError(t, err)
 	st := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epochsSinceFinalitySaveHotStateDB))
 	s.genesisTime = time.Now().Add(time.Duration(-1*int64(st)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{})
+	s.finalizedCheckpt = &ethpb.Checkpoint{}

 	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
 	assert.LogsContain(t, hook, "Entering mode to save hot states in DB")
 }

 func TestCheckSaveHotStateDB_Disabling(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
 	hook := logTest.NewGlobal()
-	opts := testServiceOptsWithDB(t)
-	s, err := NewService(context.Background(), opts...)
+	s, err := NewService(context.Background(), &Config{StateGen: stategen.New(beaconDB)})
 	require.NoError(t, err)
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{})
+	s.finalizedCheckpt = &ethpb.Checkpoint{}
 	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
 	s.genesisTime = time.Now()

@@ -324,11 +322,11 @@ func TestCheckSaveHotStateDB_Disabling(t *testing.T) {
 }

 func TestCheckSaveHotStateDB_Overflow(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
 	hook := logTest.NewGlobal()
-	opts := testServiceOptsWithDB(t)
-	s, err := NewService(context.Background(), opts...)
+	s, err := NewService(context.Background(), &Config{StateGen: stategen.New(beaconDB)})
 	require.NoError(t, err)
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 10000000})
+	s.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 10000000}
 	s.genesisTime = time.Now()

 	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
--- a/beacon-chain/blockchain/service.go
+++ b/beacon-chain/blockchain/service.go
@@ -1,9 +1,9 @@
 // Package blockchain defines the life-cycle of the blockchain at the core of
-// Ethereum, including processing of new blocks and attestations using proof of stake.
+// eth2, including processing of new blocks and attestations using casper
+// proof of stake.
 package blockchain

 import (
-	"bytes"
 	"context"
 	"fmt"
 	"runtime"
@@ -12,33 +12,29 @@ import (

 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/async/event"
-	"github.com/prysmaticlabs/prysm/beacon-chain/blockchain/store"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	f "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/slashings"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
 	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/cmd/beacon-chain/flags"
-	"github.com/prysmaticlabs/prysm/config/features"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	prysmTime "github.com/prysmaticlabs/prysm/time"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/copyutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/slotutil"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )
@@ -50,26 +46,30 @@ const headSyncMinEpochsAfterCheckpoint = 128
 // Service represents a service that handles the internal
 // logic of managing the full PoS beacon chain.
 type Service struct {
-	cfg         *config
-	ctx         context.Context
-	cancel      context.CancelFunc
-	genesisTime time.Time
-	head        *head
-	headLock    sync.RWMutex
-	// originBlockRoot is the genesis root, or weak subjectivity checkpoint root, depending on how the node is initialized
-	originBlockRoot       [32]byte
+	cfg                   *Config
+	ctx                   context.Context
+	cancel                context.CancelFunc
+	genesisTime           time.Time
+	head                  *head
+	headLock              sync.RWMutex
+	genesisRoot           [32]byte
+	justifiedCheckpt      *ethpb.Checkpoint
+	prevJustifiedCheckpt  *ethpb.Checkpoint
+	bestJustifiedCheckpt  *ethpb.Checkpoint
+	finalizedCheckpt      *ethpb.Checkpoint
+	prevFinalizedCheckpt  *ethpb.Checkpoint
 	nextEpochBoundarySlot types.Slot
 	boundaryRoots         [][32]byte
 	checkpointStateCache  *cache.CheckpointStateCache
-	initSyncBlocks        map[[32]byte]block.SignedBeaconBlock
+	initSyncBlocks        map[[32]byte]interfaces.SignedBeaconBlock
 	initSyncBlocksLock    sync.RWMutex
-	justifiedBalances     *stateBalanceCache
-	wsVerifier            *WeakSubjectivityVerifier
-	store                 *store.Store
+	justifiedBalances     []uint64
+	justifiedBalancesLock sync.RWMutex
+	wsVerified            bool
 }

-// config options for the service.
-type config struct {
+// Config options for the service.
+type Config struct {
 	BeaconBlockBuf          int
 	ChainStartFetcher       powchain.ChainStartFetcher
 	BeaconDB                db.HeadAccessDatabase
@@ -81,61 +81,229 @@ type config struct {
 	MaxRoutines             int
 	StateNotifier           statefeed.Notifier
 	ForkChoiceStore         f.ForkChoicer
-	AttService              *attestations.Service
+	OpsService              *attestations.Service
 	StateGen                *stategen.State
-	SlasherAttestationsFeed *event.Feed
 	WeakSubjectivityCheckpt *ethpb.Checkpoint
-	BlockFetcher            powchain.POWBlockFetcher
-	FinalizedStateAtStartUp state.BeaconState
-	ExecutionEngineCaller   powchain.EngineCaller
 }

 // NewService instantiates a new block service instance that will
 // be registered into a running beacon node.
-func NewService(ctx context.Context, opts ...Option) (*Service, error) {
+func NewService(ctx context.Context, cfg *Config) (*Service, error) {
 	ctx, cancel := context.WithCancel(ctx)
-	srv := &Service{
+	return &Service{
+		cfg:                  cfg,
 		ctx:                  ctx,
 		cancel:               cancel,
 		boundaryRoots:        [][32]byte{},
 		checkpointStateCache: cache.NewCheckpointStateCache(),
-		initSyncBlocks:       make(map[[32]byte]block.SignedBeaconBlock),
-		cfg:                  &config{},
-		store:                &store.Store{},
-	}
-	for _, opt := range opts {
-		if err := opt(srv); err != nil {
-			return nil, err
-		}
-	}
-	var err error
-	if srv.justifiedBalances == nil {
-		srv.justifiedBalances, err = newStateBalanceCache(srv.cfg.StateGen)
-		if err != nil {
-			return nil, err
-		}
-	}
-	srv.wsVerifier, err = NewWeakSubjectivityVerifier(srv.cfg.WeakSubjectivityCheckpt, srv.cfg.BeaconDB)
-	if err != nil {
-		return nil, err
-	}
-	return srv, nil
+		initSyncBlocks:       make(map[[32]byte]interfaces.SignedBeaconBlock),
+		justifiedBalances:    make([]uint64, 0),
+	}, nil
 }

 // Start a blockchain service's main event loop.
 func (s *Service) Start() {
-	saved := s.cfg.FinalizedStateAtStartUp
+	// For running initial sync with state cache, in an event of restart, we use
+	// last finalized check point as start point to sync instead of head
+	// state. This is because we no longer save state every slot during sync.
+	cp, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
+	if err != nil {
+		log.Fatalf("Could not fetch finalized cp: %v", err)
+	}

-	if saved != nil && !saved.IsNil() {
-		if err := s.StartFromSavedState(saved); err != nil {
-			log.Fatal(err)
+	r := bytesutil.ToBytes32(cp.Root)
+	// Before the first finalized epoch, in the current epoch,
+	// the finalized root is defined as zero hashes instead of genesis root hash.
+	// We want to use genesis root to retrieve for state.
+	if r == params.BeaconConfig().ZeroHash {
+		genesisBlock, err := s.cfg.BeaconDB.GenesisBlock(s.ctx)
+		if err != nil {
+			log.Fatalf("Could not fetch finalized cp: %v", err)
 		}
-	} else {
-		if err := s.startFromPOWChain(); err != nil {
-			log.Fatal(err)
+		if genesisBlock != nil && !genesisBlock.IsNil() {
+			r, err = genesisBlock.Block().HashTreeRoot()
+			if err != nil {
+				log.Fatalf("Could not tree hash genesis block: %v", err)
+			}
 		}
 	}
-	s.spawnProcessAttestationsRoutine(s.cfg.StateNotifier.StateFeed())
+	beaconState, err := s.cfg.StateGen.StateByRoot(s.ctx, r)
+	if err != nil {
+		log.Fatalf("Could not fetch beacon state by root: %v", err)
+	}
+
+	// Make sure that attestation processor is subscribed and ready for state initializing event.
+	attestationProcessorSubscribed := make(chan struct{}, 1)
+
+	// If the chain has already been initialized, simply start the block processing routine.
+	if beaconState != nil && !beaconState.IsNil() {
+		log.Info("Blockchain data already exists in DB, initializing...")
+		s.genesisTime = time.Unix(int64(beaconState.GenesisTime()), 0)
+		s.cfg.OpsService.SetGenesisTime(beaconState.GenesisTime())
+		if err := s.initializeChainInfo(s.ctx); err != nil {
+			log.Fatalf("Could not set up chain info: %v", err)
+		}
+
+		// We start a counter to genesis, if needed.
+		gState, err := s.cfg.BeaconDB.GenesisState(s.ctx)
+		if err != nil {
+			log.Fatalf("Could not retrieve genesis state: %v", err)
+		}
+		gRoot, err := gState.HashTreeRoot(s.ctx)
+		if err != nil {
+			log.Fatalf("Could not hash tree root genesis state: %v", err)
+		}
+		go slotutil.CountdownToGenesis(s.ctx, s.genesisTime, uint64(gState.NumValidators()), gRoot)
+
+		justifiedCheckpoint, err := s.cfg.BeaconDB.JustifiedCheckpoint(s.ctx)
+		if err != nil {
+			log.Fatalf("Could not get justified checkpoint: %v", err)
+		}
+		finalizedCheckpoint, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
+		if err != nil {
+			log.Fatalf("Could not get finalized checkpoint: %v", err)
+		}
+
+		// Resume fork choice.
+		s.justifiedCheckpt = copyutil.CopyCheckpoint(justifiedCheckpoint)
+		if err := s.cacheJustifiedStateBalances(s.ctx, s.ensureRootNotZeros(bytesutil.ToBytes32(s.justifiedCheckpt.Root))); err != nil {
+			log.Fatalf("Could not cache justified state balances: %v", err)
+		}
+		s.prevJustifiedCheckpt = copyutil.CopyCheckpoint(justifiedCheckpoint)
+		s.bestJustifiedCheckpt = copyutil.CopyCheckpoint(justifiedCheckpoint)
+		s.finalizedCheckpt = copyutil.CopyCheckpoint(finalizedCheckpoint)
+		s.prevFinalizedCheckpt = copyutil.CopyCheckpoint(finalizedCheckpoint)
+		s.resumeForkChoice(justifiedCheckpoint, finalizedCheckpoint)
+
+		ss, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+		if err != nil {
+			log.Fatalf("Could not get start slot of finalized epoch: %v", err)
+		}
+		h := s.headBlock().Block()
+		if h.Slot() > ss {
+			log.WithFields(logrus.Fields{
+				"startSlot": ss,
+				"endSlot":   h.Slot(),
+			}).Info("Loading blocks to fork choice store, this may take a while.")
+			if err := s.fillInForkChoiceMissingBlocks(s.ctx, h, s.finalizedCheckpt, s.justifiedCheckpt); err != nil {
+				log.Fatalf("Could not fill in fork choice store missing blocks: %v", err)
+			}
+		}
+
+		if err := s.VerifyWeakSubjectivityRoot(s.ctx); err != nil {
+			// Exit run time if the node failed to verify weak subjectivity checkpoint.
+			log.Fatalf("Could not verify weak subjectivity checkpoint: %v", err)
+		}
+
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+			Type: statefeed.Initialized,
+			Data: &statefeed.InitializedData{
+				StartTime:             s.genesisTime,
+				GenesisValidatorsRoot: beaconState.GenesisValidatorRoot(),
+			},
+		})
+	} else {
+		log.Info("Waiting to reach the validator deposit threshold to start the beacon chain...")
+		if s.cfg.ChainStartFetcher == nil {
+			log.Fatal("Not configured web3Service for POW chain")
+			return // return need for TestStartUninitializedChainWithoutConfigPOWChain.
+		}
+		go func() {
+			stateChannel := make(chan *feed.Event, 1)
+			stateSub := s.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
+			defer stateSub.Unsubscribe()
+			<-attestationProcessorSubscribed
+			for {
+				select {
+				case event := <-stateChannel:
+					if event.Type == statefeed.ChainStarted {
+						data, ok := event.Data.(*statefeed.ChainStartedData)
+						if !ok {
+							log.Error("event data is not type *statefeed.ChainStartedData")
+							return
+						}
+						log.WithField("starttime", data.StartTime).Debug("Received chain start event")
+						s.processChainStartTime(s.ctx, data.StartTime)
+						return
+					}
+				case <-s.ctx.Done():
+					log.Debug("Context closed, exiting goroutine")
+					return
+				case err := <-stateSub.Err():
+					log.WithError(err).Error("Subscription to state notifier failed")
+					return
+				}
+			}
+		}()
+	}
+
+	go s.processAttestationsRoutine(attestationProcessorSubscribed)
+}
+
+// processChainStartTime initializes a series of deposits from the ChainStart deposits in the eth1
+// deposit contract, initializes the beacon chain's state, and kicks off the beacon chain.
+func (s *Service) processChainStartTime(ctx context.Context, genesisTime time.Time) {
+	preGenesisState := s.cfg.ChainStartFetcher.PreGenesisState()
+	initializedState, err := s.initializeBeaconChain(ctx, genesisTime, preGenesisState, s.cfg.ChainStartFetcher.ChainStartEth1Data())
+	if err != nil {
+		log.Fatalf("Could not initialize beacon chain: %v", err)
+	}
+	// We start a counter to genesis, if needed.
+	gRoot, err := initializedState.HashTreeRoot(s.ctx)
+	if err != nil {
+		log.Fatalf("Could not hash tree root genesis state: %v", err)
+	}
+	go slotutil.CountdownToGenesis(ctx, genesisTime, uint64(initializedState.NumValidators()), gRoot)
+
+	// We send out a state initialized event to the rest of the services
+	// running in the beacon node.
+	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+		Type: statefeed.Initialized,
+		Data: &statefeed.InitializedData{
+			StartTime:             genesisTime,
+			GenesisValidatorsRoot: initializedState.GenesisValidatorRoot(),
+		},
+	})
+}
+
+// initializes the state and genesis block of the beacon chain to persistent storage
+// based on a genesis timestamp value obtained from the ChainStart event emitted
+// by the ETH1.0 Deposit Contract and the POWChain service of the node.
+func (s *Service) initializeBeaconChain(
+	ctx context.Context,
+	genesisTime time.Time,
+	preGenesisState iface.BeaconState,
+	eth1data *ethpb.Eth1Data) (iface.BeaconState, error) {
+	ctx, span := trace.StartSpan(ctx, "beacon-chain.Service.initializeBeaconChain")
+	defer span.End()
+	s.genesisTime = genesisTime
+	unixTime := uint64(genesisTime.Unix())
+
+	genesisState, err := state.OptimizedGenesisBeaconState(unixTime, preGenesisState, eth1data)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not initialize genesis state")
+	}
+
+	if err := s.saveGenesisData(ctx, genesisState); err != nil {
+		return nil, errors.Wrap(err, "could not save genesis data")
+	}
+
+	log.Info("Initialized beacon chain genesis state")
+
+	// Clear out all pre-genesis data now that the state is initialized.
+	s.cfg.ChainStartFetcher.ClearPreGenesisData()
+
+	// Update committee shuffled indices for genesis epoch.
+	if err := helpers.UpdateCommitteeCache(genesisState, 0 /* genesis epoch */); err != nil {
+		return nil, err
+	}
+	if err := helpers.UpdateProposerIndicesInCache(genesisState); err != nil {
+		return nil, err
+	}
+
+	s.cfg.OpsService.SetGenesisTime(genesisState.GenesisTime())
+
+	return genesisState, nil
 }

 // Stop the blockchain service's main event loop and associated goroutines.
@@ -155,7 +323,7 @@ func (s *Service) Stop() error {
 // Status always returns nil unless there is an error condition that causes
 // this service to be unhealthy.
 func (s *Service) Status() error {
-	if s.originBlockRoot == params.BeaconConfig().ZeroHash {
+	if s.genesisRoot == params.BeaconConfig().ZeroHash {
 		return errors.New("genesis state has not been created")
 	}
 	if runtime.NumGoroutine() > s.cfg.MaxRoutines {
@@ -164,126 +332,64 @@ func (s *Service) Status() error {
 	return nil
 }

-func (s *Service) StartFromSavedState(saved state.BeaconState) error {
-	log.Info("Blockchain data already exists in DB, initializing...")
-	s.genesisTime = time.Unix(int64(saved.GenesisTime()), 0) // lint:ignore uintcast -- Genesis time will not exceed int64 in your lifetime.
-	s.cfg.AttService.SetGenesisTime(saved.GenesisTime())
-
-	originRoot, err := s.originRootFromSavedState(s.ctx)
+// This gets called when beacon chain is first initialized to save genesis data (state, block, and more) in db.
+func (s *Service) saveGenesisData(ctx context.Context, genesisState iface.BeaconState) error {
+	if err := s.cfg.BeaconDB.SaveGenesisData(ctx, genesisState); err != nil {
+		return errors.Wrap(err, "could not save genesis data")
+	}
+	genesisBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
+	if err != nil || genesisBlk == nil || genesisBlk.IsNil() {
+		return fmt.Errorf("could not load genesis block: %v", err)
+	}
+	genesisBlkRoot, err := genesisBlk.Block().HashTreeRoot()
 	if err != nil {
+		return errors.Wrap(err, "could not get genesis block root")
+	}
+
+	s.genesisRoot = genesisBlkRoot
+	s.cfg.StateGen.SaveFinalizedState(0 /*slot*/, genesisBlkRoot, genesisState)
+
+	// Finalized checkpoint at genesis is a zero hash.
+	genesisCheckpoint := genesisState.FinalizedCheckpoint()
+
+	s.justifiedCheckpt = copyutil.CopyCheckpoint(genesisCheckpoint)
+	if err := s.cacheJustifiedStateBalances(ctx, genesisBlkRoot); err != nil {
 		return err
 	}
-	s.originBlockRoot = originRoot
+	s.prevJustifiedCheckpt = copyutil.CopyCheckpoint(genesisCheckpoint)
+	s.bestJustifiedCheckpt = copyutil.CopyCheckpoint(genesisCheckpoint)
+	s.finalizedCheckpt = copyutil.CopyCheckpoint(genesisCheckpoint)
+	s.prevFinalizedCheckpt = copyutil.CopyCheckpoint(genesisCheckpoint)

-	if err := s.initializeHeadFromDB(s.ctx); err != nil {
-		return errors.Wrap(err, "could not set up chain info")
-	}
-	spawnCountdownIfPreGenesis(s.ctx, s.genesisTime, s.cfg.BeaconDB)
-
-	justified, err := s.cfg.BeaconDB.JustifiedCheckpoint(s.ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not get justified checkpoint")
-	}
-	finalized, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized checkpoint")
-	}
-	s.store = store.New(justified, finalized)
-
-	var f f.ForkChoicer
-	fRoot := bytesutil.ToBytes32(finalized.Root)
-	if features.Get().EnableForkChoiceDoublyLinkedTree {
-		f = doublylinkedtree.New(justified.Epoch, finalized.Epoch)
-	} else {
-		f = protoarray.New(justified.Epoch, finalized.Epoch, fRoot)
-	}
-	s.cfg.ForkChoiceStore = f
-	fb, err := s.cfg.BeaconDB.Block(s.ctx, s.ensureRootNotZeros(fRoot))
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized checkpoint block")
-	}
-	if fb == nil {
-		return errNilFinalizedInStore
-	}
-	payloadHash, err := getBlockPayloadHash(fb.Block())
-	if err != nil {
-		return errors.Wrap(err, "could not get execution payload hash")
-	}
-	fSlot := fb.Block().Slot()
-	if err := f.InsertOptimisticBlock(s.ctx, fSlot, fRoot, params.BeaconConfig().ZeroHash,
-		payloadHash, justified.Epoch, finalized.Epoch); err != nil {
-		return errors.Wrap(err, "could not insert finalized block to forkchoice")
+	if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
+		genesisBlk.Block().Slot(),
+		genesisBlkRoot,
+		params.BeaconConfig().ZeroHash,
+		[32]byte{},
+		genesisCheckpoint.Epoch,
+		genesisCheckpoint.Epoch); err != nil {
+		log.Fatalf("Could not process genesis block for fork choice: %v", err)
 	}

-	lastValidatedCheckpoint, err := s.cfg.BeaconDB.LastValidatedCheckpoint(s.ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not get last validated checkpoint")
-	}
-	if bytes.Equal(finalized.Root, lastValidatedCheckpoint.Root) {
-		if err := f.SetOptimisticToValid(s.ctx, fRoot); err != nil {
-			return errors.Wrap(err, "could not set finalized block as validated")
-		}
-	}
-
-	h := s.headBlock().Block()
-	if h.Slot() > fSlot {
-		log.WithFields(logrus.Fields{
-			"startSlot": fSlot,
-			"endSlot":   h.Slot(),
-		}).Info("Loading blocks to fork choice store, this may take a while.")
-		if err := s.fillInForkChoiceMissingBlocks(s.ctx, h, finalized, justified); err != nil {
-			return errors.Wrap(err, "could not fill in fork choice store missing blocks")
-		}
-	}
-
-	// not attempting to save initial sync blocks here, because there shouldn't be any until
-	// after the statefeed.Initialized event is fired (below)
-	if err := s.wsVerifier.VerifyWeakSubjectivity(s.ctx, finalized.Epoch); err != nil {
-		// Exit run time if the node failed to verify weak subjectivity checkpoint.
-		return errors.Wrap(err, "could not verify initial checkpoint provided for chain sync")
-	}
-
-	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.Initialized,
-		Data: &statefeed.InitializedData{
-			StartTime:             s.genesisTime,
-			GenesisValidatorsRoot: saved.GenesisValidatorsRoot(),
-		},
-	})
-
+	s.setHead(genesisBlkRoot, genesisBlk, genesisState)
 	return nil
 }

-func (s *Service) originRootFromSavedState(ctx context.Context) ([32]byte, error) {
-	// first check if we have started from checkpoint sync and have a root
-	originRoot, err := s.cfg.BeaconDB.OriginCheckpointBlockRoot(ctx)
-	if err == nil {
-		return originRoot, nil
-	}
-	if !errors.Is(err, db.ErrNotFound) {
-		return originRoot, errors.Wrap(err, "could not retrieve checkpoint sync chain origin data from db")
-	}
-
-	// we got here because OriginCheckpointBlockRoot gave us an ErrNotFound. this means the node was started from a genesis state,
-	// so we should have a value for GenesisBlock
+// This gets called to initialize chain info variables using the finalized checkpoint stored in DB
+func (s *Service) initializeChainInfo(ctx context.Context) error {
 	genesisBlock, err := s.cfg.BeaconDB.GenesisBlock(ctx)
 	if err != nil {
-		return originRoot, errors.Wrap(err, "could not get genesis block from db")
+		return errors.Wrap(err, "could not get genesis block from db")
 	}
-	if err := helpers.BeaconBlockIsNil(genesisBlock); err != nil {
-		return originRoot, err
+	if genesisBlock == nil || genesisBlock.IsNil() {
+		return errors.New("no genesis block in db")
 	}
 	genesisBlkRoot, err := genesisBlock.Block().HashTreeRoot()
 	if err != nil {
-		return genesisBlkRoot, errors.Wrap(err, "could not get signing root of genesis block")
+		return errors.Wrap(err, "could not get signing root of genesis block")
 	}
-	return genesisBlkRoot, nil
-}
+	s.genesisRoot = genesisBlkRoot

-// initializeHeadFromDB uses the finalized checkpoint and head block found in the database to set the current head
-// note that this may block until stategen replays blocks between the finalized and head blocks
-// if the head sync flag was specified and the gap between the finalized and head blocks is at least 128 epochs long
-func (s *Service) initializeHeadFromDB(ctx context.Context) error {
 	finalized, err := s.cfg.BeaconDB.FinalizedCheckpoint(ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized checkpoint from db")
@@ -294,9 +400,9 @@ func (s *Service) initializeHeadFromDB(ctx context.Context) error {
 		return errors.New("no finalized epoch in the database")
 	}
 	finalizedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
-	var finalizedState state.BeaconState
+	var finalizedState iface.BeaconState

-	finalizedState, err = s.cfg.StateGen.Resume(ctx, s.cfg.FinalizedStateAtStartUp)
+	finalizedState, err = s.cfg.StateGen.Resume(ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized state from db")
 	}
@@ -306,7 +412,7 @@ func (s *Service) initializeHeadFromDB(ctx context.Context) error {
 		if err != nil {
 			return errors.Wrap(err, "could not retrieve head block")
 		}
-		headEpoch := slots.ToEpoch(headBlock.Block().Slot())
+		headEpoch := helpers.SlotToEpoch(headBlock.Block().Slot())
 		var epochsSinceFinality types.Epoch
 		if headEpoch > finalized.Epoch {
 			epochsSinceFinality = headEpoch - finalized.Epoch
@@ -318,7 +424,7 @@ func (s *Service) initializeHeadFromDB(ctx context.Context) error {
 			if err != nil {
 				return errors.Wrap(err, "could not hash head block")
 			}
-			finalizedState, err := s.cfg.StateGen.Resume(ctx, s.cfg.FinalizedStateAtStartUp)
+			finalizedState, err := s.cfg.StateGen.Resume(ctx)
 			if err != nil {
 				return errors.Wrap(err, "could not get finalized state from db")
 			}
@@ -350,147 +456,11 @@ func (s *Service) initializeHeadFromDB(ctx context.Context) error {
 	return nil
 }

-func (s *Service) startFromPOWChain() error {
-	log.Info("Waiting to reach the validator deposit threshold to start the beacon chain...")
-	if s.cfg.ChainStartFetcher == nil {
-		return errors.New("not configured web3Service for POW chain")
-	}
-	go func() {
-		stateChannel := make(chan *feed.Event, 1)
-		stateSub := s.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
-		defer stateSub.Unsubscribe()
-		for {
-			select {
-			case e := <-stateChannel:
-				if e.Type == statefeed.ChainStarted {
-					data, ok := e.Data.(*statefeed.ChainStartedData)
-					if !ok {
-						log.Error("event data is not type *statefeed.ChainStartedData")
-						return
-					}
-					log.WithField("starttime", data.StartTime).Debug("Received chain start event")
-					s.onPowchainStart(s.ctx, data.StartTime)
-					return
-				}
-			case <-s.ctx.Done():
-				log.Debug("Context closed, exiting goroutine")
-				return
-			case err := <-stateSub.Err():
-				log.WithError(err).Error("Subscription to state notifier failed")
-				return
-			}
-		}
-	}()
-
-	return nil
-}
-
-// onPowchainStart initializes a series of deposits from the ChainStart deposits in the eth1
-// deposit contract, initializes the beacon chain's state, and kicks off the beacon chain.
-func (s *Service) onPowchainStart(ctx context.Context, genesisTime time.Time) {
-	preGenesisState := s.cfg.ChainStartFetcher.PreGenesisState()
-	initializedState, err := s.initializeBeaconChain(ctx, genesisTime, preGenesisState, s.cfg.ChainStartFetcher.ChainStartEth1Data())
-	if err != nil {
-		log.Fatalf("Could not initialize beacon chain: %v", err)
-	}
-	// We start a counter to genesis, if needed.
-	gRoot, err := initializedState.HashTreeRoot(s.ctx)
-	if err != nil {
-		log.Fatalf("Could not hash tree root genesis state: %v", err)
-	}
-	go slots.CountdownToGenesis(ctx, genesisTime, uint64(initializedState.NumValidators()), gRoot)
-
-	// We send out a state initialized event to the rest of the services
-	// running in the beacon node.
-	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.Initialized,
-		Data: &statefeed.InitializedData{
-			StartTime:             genesisTime,
-			GenesisValidatorsRoot: initializedState.GenesisValidatorsRoot(),
-		},
-	})
-}
-
-// initializes the state and genesis block of the beacon chain to persistent storage
-// based on a genesis timestamp value obtained from the ChainStart event emitted
-// by the ETH1.0 Deposit Contract and the POWChain service of the node.
-func (s *Service) initializeBeaconChain(
-	ctx context.Context,
-	genesisTime time.Time,
-	preGenesisState state.BeaconState,
-	eth1data *ethpb.Eth1Data) (state.BeaconState, error) {
-	ctx, span := trace.StartSpan(ctx, "beacon-chain.Service.initializeBeaconChain")
-	defer span.End()
-	s.genesisTime = genesisTime
-	unixTime := uint64(genesisTime.Unix())
-
-	genesisState, err := transition.OptimizedGenesisBeaconState(unixTime, preGenesisState, eth1data)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not initialize genesis state")
-	}
-
-	if err := s.saveGenesisData(ctx, genesisState); err != nil {
-		return nil, errors.Wrap(err, "could not save genesis data")
-	}
-
-	log.Info("Initialized beacon chain genesis state")
-
-	// Clear out all pre-genesis data now that the state is initialized.
-	s.cfg.ChainStartFetcher.ClearPreGenesisData()
-
-	// Update committee shuffled indices for genesis epoch.
-	if err := helpers.UpdateCommitteeCache(genesisState, 0 /* genesis epoch */); err != nil {
-		return nil, err
-	}
-	if err := helpers.UpdateProposerIndicesInCache(ctx, genesisState); err != nil {
-		return nil, err
-	}
-
-	s.cfg.AttService.SetGenesisTime(genesisState.GenesisTime())
-
-	return genesisState, nil
-}
-
-// This gets called when beacon chain is first initialized to save genesis data (state, block, and more) in db.
-func (s *Service) saveGenesisData(ctx context.Context, genesisState state.BeaconState) error {
-	if err := s.cfg.BeaconDB.SaveGenesisData(ctx, genesisState); err != nil {
-		return errors.Wrap(err, "could not save genesis data")
-	}
-	genesisBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
-	if err != nil || genesisBlk == nil || genesisBlk.IsNil() {
-		return fmt.Errorf("could not load genesis block: %v", err)
-	}
-	genesisBlkRoot, err := genesisBlk.Block().HashTreeRoot()
-	if err != nil {
-		return errors.Wrap(err, "could not get genesis block root")
-	}
-
-	s.originBlockRoot = genesisBlkRoot
-	s.cfg.StateGen.SaveFinalizedState(0 /*slot*/, genesisBlkRoot, genesisState)
-
-	// Finalized checkpoint at genesis is a zero hash.
-	genesisCheckpoint := genesisState.FinalizedCheckpoint()
-	s.store = store.New(genesisCheckpoint, genesisCheckpoint)
-
-	payloadHash, err := getBlockPayloadHash(genesisBlk.Block())
-	if err != nil {
-		return err
-	}
-	if err := s.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx,
-		genesisBlk.Block().Slot(),
-		genesisBlkRoot,
-		params.BeaconConfig().ZeroHash,
-		payloadHash,
-		genesisCheckpoint.Epoch,
-		genesisCheckpoint.Epoch); err != nil {
-		log.Fatalf("Could not process genesis block for fork choice: %v", err)
-	}
-	if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, genesisBlkRoot); err != nil {
-		log.Fatalf("Could not set optimistic status of genesis block to false: %v", err)
-	}
-
-	s.setHead(genesisBlkRoot, genesisBlk, genesisState)
-	return nil
+// This is called when a client starts from non-genesis slot. This passes last justified and finalized
+// information to fork choice service to initializes fork choice store.
+func (s *Service) resumeForkChoice(justifiedCheckpoint, finalizedCheckpoint *ethpb.Checkpoint) {
+	store := protoarray.New(justifiedCheckpoint.Epoch, finalizedCheckpoint.Epoch, bytesutil.ToBytes32(finalizedCheckpoint.Root))
+	s.cfg.ForkChoiceStore = store
 }

 // This returns true if block has been processed before. Two ways to verify the block has been processed:
@@ -504,20 +474,3 @@ func (s *Service) hasBlock(ctx context.Context, root [32]byte) bool {

 	return s.cfg.BeaconDB.HasBlock(ctx, root)
 }
-
-func spawnCountdownIfPreGenesis(ctx context.Context, genesisTime time.Time, db db.HeadAccessDatabase) {
-	currentTime := prysmTime.Now()
-	if currentTime.After(genesisTime) {
-		return
-	}
-
-	gState, err := db.GenesisState(ctx)
-	if err != nil {
-		log.Fatalf("Could not retrieve genesis state: %v", err)
-	}
-	gRoot, err := gState.HashTreeRoot(ctx)
-	if err != nil {
-		log.Fatalf("Could not hash tree root genesis state: %v", err)
-	}
-	go slots.CountdownToGenesis(ctx, genesisTime, uint64(gState.NumValidators()), gRoot)
-}
--- a/beacon-chain/blockchain/service_norace_test.go
+++ b/beacon-chain/blockchain/service_norace_test.go
@@ -6,7 +6,7 @@ import (
 	"testing"

 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/testing/require"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	"github.com/sirupsen/logrus"
 )

@@ -18,7 +18,7 @@ func init() {
 func TestChainService_SaveHead_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		cfg: &config{BeaconDB: beaconDB},
+		cfg: &Config{BeaconDB: beaconDB},
 	}
 	go func() {
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
--- a/beacon-chain/blockchain/service_test.go
+++ b/beacon-chain/blockchain/service_test.go
@@ -8,35 +8,31 @@ import (
 	"time"

 	"github.com/ethereum/go-ethereum/common"
-	"github.com/prysmaticlabs/prysm/async/event"
-	"github.com/prysmaticlabs/prysm/beacon-chain/blockchain/store"
-	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache"
 	b "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
 	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
-	mockPOW "github.com/prysmaticlabs/prysm/beacon-chain/powchain/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	"github.com/prysmaticlabs/prysm/cmd/beacon-chain/flags"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	protodb "github.com/prysmaticlabs/prysm/proto/beacon/db"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/event"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 	"google.golang.org/protobuf/proto"
 )
@@ -67,72 +63,62 @@ func (mb *mockBroadcaster) BroadcastAttestation(_ context.Context, _ uint64, _ *
 	return nil
 }

-func (mb *mockBroadcaster) BroadcastSyncCommitteeMessage(_ context.Context, _ uint64, _ *ethpb.SyncCommitteeMessage) error {
-	mb.broadcastCalled = true
-	return nil
-}
-
 var _ p2p.Broadcaster = (*mockBroadcaster)(nil)

 func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
+	endpoint := "http://127.0.0.1"
 	ctx := context.Background()
 	var web3Service *powchain.Service
 	var err error
-	srv, endpoint, err := mockPOW.SetupRPCServer()
+	bState, _ := testutil.DeterministicGenesisState(t, 10)
+	pbState, err := stateV0.ProtobufBeaconState(bState.InnerStateUnsafe())
 	require.NoError(t, err)
-	t.Cleanup(func() {
-		srv.Stop()
-	})
-	bState, _ := util.DeterministicGenesisState(t, 10)
-	pbState, err := v1.ProtobufBeaconState(bState.InnerStateUnsafe())
-	require.NoError(t, err)
-	err = beaconDB.SavePowchainData(ctx, &ethpb.ETH1ChainData{
+	err = beaconDB.SavePowchainData(ctx, &protodb.ETH1ChainData{
 		BeaconState: pbState,
-		Trie:        &ethpb.SparseMerkleTrie{},
-		CurrentEth1Data: &ethpb.LatestETH1Data{
+		Trie:        &protodb.SparseMerkleTrie{},
+		CurrentEth1Data: &protodb.LatestETH1Data{
 			BlockHash: make([]byte, 32),
 		},
-		ChainstartData: &ethpb.ChainStartData{
+		ChainstartData: &protodb.ChainStartData{
 			Eth1Data: &ethpb.Eth1Data{
 				DepositRoot:  make([]byte, 32),
 				DepositCount: 0,
 				BlockHash:    make([]byte, 32),
 			},
 		},
-		DepositContainers: []*ethpb.DepositContainer{},
+		DepositContainers: []*protodb.DepositContainer{},
 	})
 	require.NoError(t, err)
-	web3Service, err = powchain.NewService(
-		ctx,
-		powchain.WithDatabase(beaconDB),
-		powchain.WithHttpEndpoints([]string{endpoint}),
-		powchain.WithDepositContractAddress(common.Address{}),
-	)
+	web3Service, err = powchain.NewService(ctx, &powchain.Web3ServiceConfig{
+		BeaconDB:        beaconDB,
+		HttpEndpoints:   []string{endpoint},
+		DepositContract: common.Address{},
+	})
 	require.NoError(t, err, "Unable to set up web3 service")

-	attService, err := attestations.NewService(ctx, &attestations.Config{Pool: attestations.NewPool()})
+	opsService, err := attestations.NewService(ctx, &attestations.Config{Pool: attestations.NewPool()})
 	require.NoError(t, err)

 	depositCache, err := depositcache.New()
 	require.NoError(t, err)

-	stateGen := stategen.New(beaconDB)
-	// Safe a state in stategen to purposes of testing a service stop / shutdown.
-	require.NoError(t, stateGen.SaveState(ctx, bytesutil.ToBytes32(bState.FinalizedCheckpoint().Root), bState))
-
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithDepositCache(depositCache),
-		WithChainStartFetcher(web3Service),
-		WithAttestationPool(attestations.NewPool()),
-		WithP2PBroadcaster(&mockBroadcaster{}),
-		WithStateNotifier(&mockBeaconNode{}),
-		WithForkChoiceStore(protoarray.New(0, 0, params.BeaconConfig().ZeroHash)),
-		WithAttestationService(attService),
-		WithStateGen(stateGen),
+	cfg := &Config{
+		BeaconBlockBuf:    0,
+		BeaconDB:          beaconDB,
+		DepositCache:      depositCache,
+		ChainStartFetcher: web3Service,
+		P2p:               &mockBroadcaster{},
+		StateNotifier:     &mockBeaconNode{},
+		AttPool:           attestations.NewPool(),
+		StateGen:          stategen.New(beaconDB),
+		ForkChoiceStore:   protoarray.New(0, 0, params.BeaconConfig().ZeroHash),
+		OpsService:        opsService,
 	}

-	chainService, err := NewService(ctx, opts...)
+	// Safe a state in stategen to purposes of testing a service stop / shutdown.
+	require.NoError(t, cfg.StateGen.SaveState(ctx, bytesutil.ToBytes32(bState.FinalizedCheckpoint().Root), bState))
+
+	chainService, err := NewService(ctx, cfg)
 	require.NoError(t, err, "Unable to setup chain service")
 	chainService.genesisTime = time.Unix(1, 0) // non-zero time

@@ -146,13 +132,11 @@ func TestChainStartStop_Initialized(t *testing.T) {

 	chainService := setupBeaconChain(t, beaconDB)

-	genesisBlk := util.NewBeaconBlock()
+	genesisBlk := testutil.NewBeaconBlock()
 	blkRoot, err := genesisBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(genesisBlk)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-	s, err := util.NewBeaconState()
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(genesisBlk)))
+	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, s.SetSlot(1))
 	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
@@ -160,12 +144,7 @@ func TestChainStartStop_Initialized(t *testing.T) {
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
 	require.NoError(t, beaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
 	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
-	ss := &ethpb.StateSummary{
-		Slot: 1,
-		Root: blkRoot[:],
-	}
-	require.NoError(t, beaconDB.SaveStateSummary(ctx, ss))
-	chainService.cfg.FinalizedStateAtStartUp = s
+
 	// Test the start function.
 	chainService.Start()

@@ -183,20 +162,16 @@ func TestChainStartStop_GenesisZeroHashes(t *testing.T) {

 	chainService := setupBeaconChain(t, beaconDB)

-	genesisBlk := util.NewBeaconBlock()
+	genesisBlk := testutil.NewBeaconBlock()
 	blkRoot, err := genesisBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(genesisBlk)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-	s, err := util.NewBeaconState()
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(genesisBlk)))
+	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
 	require.NoError(t, beaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}))
-	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
-	chainService.cfg.FinalizedStateAtStartUp = s
+
 	// Test the start function.
 	chainService.Start()

@@ -217,12 +192,12 @@ func TestChainService_InitializeBeaconChain(t *testing.T) {

 	// Set up 10 deposits pre chain start for validators to register
 	count := uint64(10)
-	deposits, _, err := util.DeterministicDepositsAndKeys(count)
+	deposits, _, err := testutil.DeterministicDepositsAndKeys(count)
 	require.NoError(t, err)
-	trie, _, err := util.DepositTrieFromDeposits(deposits)
+	trie, _, err := testutil.DepositTrieFromDeposits(deposits)
 	require.NoError(t, err)
 	hashTreeRoot := trie.HashTreeRoot()
-	genState, err := transition.EmptyGenesisState()
+	genState, err := state.EmptyGenesisState()
 	require.NoError(t, err)
 	err = genState.SetEth1Data(&ethpb.Eth1Data{
 		DepositRoot:  hashTreeRoot[:],
@@ -256,25 +231,23 @@ func TestChainService_CorrectGenesisRoots(t *testing.T) {

 	chainService := setupBeaconChain(t, beaconDB)

-	genesisBlk := util.NewBeaconBlock()
+	genesisBlk := testutil.NewBeaconBlock()
 	blkRoot, err := genesisBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(genesisBlk)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-	s, err := util.NewBeaconState()
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(genesisBlk)))
+	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, s.SetSlot(0))
 	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
 	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, blkRoot))
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
 	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
-	chainService.cfg.FinalizedStateAtStartUp = s
+
 	// Test the start function.
 	chainService.Start()

-	require.DeepEqual(t, blkRoot[:], chainService.store.FinalizedCheckpt().Root, "Finalize Checkpoint root is incorrect")
-	require.DeepEqual(t, params.BeaconConfig().ZeroHash[:], chainService.store.JustifiedCheckpt().Root, "Justified Checkpoint root is incorrect")
+	require.DeepEqual(t, blkRoot[:], chainService.finalizedCheckpt.Root, "Finalize Checkpoint root is incorrect")
+	require.DeepEqual(t, params.BeaconConfig().ZeroHash[:], chainService.justifiedCheckpt.Root, "Justified Checkpoint root is incorrect")

 	require.NoError(t, chainService.Stop(), "Unable to stop chain service")

@@ -284,37 +257,28 @@ func TestChainService_InitializeChainInfo(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()

-	genesis := util.NewBeaconBlock()
+	genesis := testutil.NewBeaconBlock()
 	genesisRoot, err := genesis.Block.HashTreeRoot()
 	require.NoError(t, err)
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
-	wsb, err := wrapper.WrappedSignedBeaconBlock(genesis)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(genesis)))

 	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
-	headBlock := util.NewBeaconBlock()
+	headBlock := testutil.NewBeaconBlock()
 	headBlock.Block.Slot = finalizedSlot
 	headBlock.Block.ParentRoot = bytesutil.PadTo(genesisRoot[:], 32)
-	headState, err := util.NewBeaconState()
+	headState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, headState.SetSlot(finalizedSlot))
-	require.NoError(t, headState.SetGenesisValidatorsRoot(params.BeaconConfig().ZeroHash[:]))
+	require.NoError(t, headState.SetGenesisValidatorRoot(params.BeaconConfig().ZeroHash[:]))
 	headRoot, err := headBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
 	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
 	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
-	wsb, err = wrapper.WrappedSignedBeaconBlock(headBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Epoch: slots.ToEpoch(finalizedSlot), Root: headRoot[:]}))
-	attSrv, err := attestations.NewService(ctx, &attestations.Config{})
-	require.NoError(t, err)
-	stateGen := stategen.New(beaconDB)
-	c, err := NewService(ctx, WithDatabase(beaconDB), WithStateGen(stateGen), WithAttestationService(attSrv), WithStateNotifier(&mock.MockStateNotifier{}), WithFinalizedStateAtStartUp(headState))
-	require.NoError(t, err)
-	require.NoError(t, stateGen.SaveState(ctx, headRoot, headState))
-	require.NoError(t, c.StartFromSavedState(headState))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(headBlock)))
+	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Epoch: helpers.SlotToEpoch(finalizedSlot), Root: headRoot[:]}))
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}
+	require.NoError(t, c.initializeChainInfo(ctx))
 	headBlk, err := c.HeadBlock(ctx)
 	require.NoError(t, err)
 	assert.DeepEqual(t, headBlock, headBlk.Proto(), "Head block incorrect")
@@ -327,54 +291,39 @@ func TestChainService_InitializeChainInfo(t *testing.T) {
 	if !bytes.Equal(headRoot[:], r) {
 		t.Error("head slot incorrect")
 	}
-	assert.Equal(t, genesisRoot, c.originBlockRoot, "Genesis block root incorrect")
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
 }

 func TestChainService_InitializeChainInfo_SetHeadAtGenesis(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()

-	genesis := util.NewBeaconBlock()
+	genesis := testutil.NewBeaconBlock()
 	genesisRoot, err := genesis.Block.HashTreeRoot()
 	require.NoError(t, err)
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
-	wsb, err := wrapper.WrappedSignedBeaconBlock(genesis)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(genesis)))

 	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
-	headBlock := util.NewBeaconBlock()
+	headBlock := testutil.NewBeaconBlock()
 	headBlock.Block.Slot = finalizedSlot
 	headBlock.Block.ParentRoot = bytesutil.PadTo(genesisRoot[:], 32)
-	headState, err := util.NewBeaconState()
+	headState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, headState.SetSlot(finalizedSlot))
-	require.NoError(t, headState.SetGenesisValidatorsRoot(params.BeaconConfig().ZeroHash[:]))
+	require.NoError(t, headState.SetGenesisValidatorRoot(params.BeaconConfig().ZeroHash[:]))
 	headRoot, err := headBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
 	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
 	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
-	wsb, err = wrapper.WrappedSignedBeaconBlock(headBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
-	attSrv, err := attestations.NewService(ctx, &attestations.Config{})
-	require.NoError(t, err)
-	ss := &ethpb.StateSummary{
-		Slot: finalizedSlot,
-		Root: headRoot[:],
-	}
-	require.NoError(t, beaconDB.SaveStateSummary(ctx, ss))
-	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: headRoot[:], Epoch: slots.ToEpoch(finalizedSlot)}))
-	stateGen := stategen.New(beaconDB)
-	c, err := NewService(ctx, WithDatabase(beaconDB), WithStateGen(stateGen), WithAttestationService(attSrv), WithStateNotifier(&mock.MockStateNotifier{}), WithFinalizedStateAtStartUp(headState))
-	require.NoError(t, err)
-
-	require.NoError(t, c.StartFromSavedState(headState))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(headBlock)))
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}
+	require.NoError(t, c.initializeChainInfo(ctx))
 	s, err := c.HeadState(ctx)
 	require.NoError(t, err)
 	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
-	assert.Equal(t, genesisRoot, c.originBlockRoot, "Genesis block root incorrect")
-	assert.DeepEqual(t, headBlock, c.head.block.Proto())
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
+	assert.DeepEqual(t, genesis, c.head.block.Proto())
 }

 func TestChainService_InitializeChainInfo_HeadSync(t *testing.T) {
@@ -391,78 +340,68 @@ func TestChainService_InitializeChainInfo_HeadSync(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()

-	genesisBlock := util.NewBeaconBlock()
+	genesisBlock := testutil.NewBeaconBlock()
 	genesisRoot, err := genesisBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
-	wsb, err := wrapper.WrappedSignedBeaconBlock(genesisBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(genesisBlock)))

-	finalizedBlock := util.NewBeaconBlock()
+	finalizedBlock := testutil.NewBeaconBlock()
 	finalizedBlock.Block.Slot = finalizedSlot
 	finalizedBlock.Block.ParentRoot = genesisRoot[:]
 	finalizedRoot, err := finalizedBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(finalizedBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(finalizedBlock)))

 	// Set head slot close to the finalization point, no head sync is triggered.
-	headBlock := util.NewBeaconBlock()
+	headBlock := testutil.NewBeaconBlock()
 	headBlock.Block.Slot = finalizedSlot + params.BeaconConfig().SlotsPerEpoch*5
 	headBlock.Block.ParentRoot = finalizedRoot[:]
 	headRoot, err := headBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(headBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(headBlock)))

-	headState, err := util.NewBeaconState()
+	headState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, headState.SetSlot(headBlock.Block.Slot))
-	require.NoError(t, headState.SetGenesisValidatorsRoot(params.BeaconConfig().ZeroHash[:]))
-	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
+	require.NoError(t, headState.SetGenesisValidatorRoot(params.BeaconConfig().ZeroHash[:]))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
 	require.NoError(t, beaconDB.SaveState(ctx, headState, finalizedRoot))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
 	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, headRoot))
 	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{
-		Epoch: slots.ToEpoch(finalizedBlock.Block.Slot),
+		Epoch: helpers.SlotToEpoch(finalizedBlock.Block.Slot),
 		Root:  finalizedRoot[:],
 	}))

-	attSrv, err := attestations.NewService(ctx, &attestations.Config{})
-	require.NoError(t, err)
-	stateGen := stategen.New(beaconDB)
-	c, err := NewService(ctx, WithDatabase(beaconDB), WithStateGen(stateGen), WithAttestationService(attSrv), WithStateNotifier(&mock.MockStateNotifier{}), WithFinalizedStateAtStartUp(headState))
-	require.NoError(t, err)
-	require.NoError(t, c.StartFromSavedState(headState))
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}
+
+	require.NoError(t, c.initializeChainInfo(ctx))
 	s, err := c.HeadState(ctx)
 	require.NoError(t, err)
 	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
-	assert.Equal(t, genesisRoot, c.originBlockRoot, "Genesis block root incorrect")
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
 	// Since head sync is not triggered, chain is initialized to the last finalization checkpoint.
 	assert.DeepEqual(t, finalizedBlock, c.head.block.Proto())
 	assert.LogsContain(t, hook, "resetting head from the checkpoint ('--head-sync' flag is ignored)")
 	assert.LogsDoNotContain(t, hook, "Regenerating state from the last checkpoint at slot")

 	// Set head slot far beyond the finalization point, head sync should be triggered.
-	headBlock = util.NewBeaconBlock()
+	headBlock = testutil.NewBeaconBlock()
 	headBlock.Block.Slot = finalizedSlot + params.BeaconConfig().SlotsPerEpoch*headSyncMinEpochsAfterCheckpoint
 	headBlock.Block.ParentRoot = finalizedRoot[:]
 	headRoot, err = headBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err = wrapper.WrappedSignedBeaconBlock(headBlock)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
+	require.NoError(t, beaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(headBlock)))
 	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
 	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, headRoot))

 	hook.Reset()
-	require.NoError(t, c.initializeHeadFromDB(ctx))
+	require.NoError(t, c.initializeChainInfo(ctx))
 	s, err = c.HeadState(ctx)
 	require.NoError(t, err)
 	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
-	assert.Equal(t, genesisRoot, c.originBlockRoot, "Genesis block root incorrect")
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
 	// Head slot is far beyond the latest finalized checkpoint, head sync is triggered.
 	assert.DeepEqual(t, headBlock, c.head.block.Proto())
 	assert.LogsContain(t, hook, "Regenerating state from the last checkpoint at slot 225")
@@ -473,18 +412,16 @@ func TestChainService_SaveHeadNoDB(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()
 	s := &Service{
-		cfg: &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 	}
-	blk := util.NewBeaconBlock()
+	blk := testutil.NewBeaconBlock()
 	blk.Block.Slot = 1
 	r, err := blk.HashTreeRoot()
 	require.NoError(t, err)
-	newState, err := util.NewBeaconState()
+	newState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, s.cfg.StateGen.SaveState(ctx, r, newState))
-	wsb, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(t, err)
-	require.NoError(t, s.saveHeadNoDB(ctx, wsb, r, newState))
+	require.NoError(t, s.saveHeadNoDB(ctx, interfaces.WrappedPhase0SignedBeaconBlock(blk), r, newState))

 	newB, err := s.cfg.BeaconDB.HeadBlock(ctx)
 	require.NoError(t, err)
@@ -493,43 +430,19 @@ func TestChainService_SaveHeadNoDB(t *testing.T) {
 	}
 }

-func TestHasBlock_ForkChoiceAndDB_ProtoArray(t *testing.T) {
+func TestHasBlock_ForkChoiceAndDB(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		cfg:   &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
-		store: &store.Store{},
+		cfg:              &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
+		finalizedCheckpt: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash[:]})
-	b := util.NewBeaconBlock()
-	r, err := b.Block.HashTreeRoot()
+	block := testutil.NewBeaconBlock()
+	r, err := block.Block.HashTreeRoot()
 	require.NoError(t, err)
-	beaconState, err := util.NewBeaconState()
+	beaconState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, s.insertBlockAndAttestationsToForkChoiceStore(ctx, wsb.Block(), r, beaconState))
-
-	assert.Equal(t, false, s.hasBlock(ctx, [32]byte{}), "Should not have block")
-	assert.Equal(t, true, s.hasBlock(ctx, r), "Should have block")
-}
-
-func TestHasBlock_ForkChoiceAndDB_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	s := &Service{
-		cfg:   &config{ForkChoiceStore: doublylinkedtree.New(0, 0), BeaconDB: beaconDB},
-		store: &store.Store{},
-	}
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash[:]})
-	b := util.NewBeaconBlock()
-	r, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	beaconState, err := util.NewBeaconState()
-	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, s.insertBlockAndAttestationsToForkChoiceStore(ctx, wsb.Block(), r, beaconState))
+	require.NoError(t, s.insertBlockAndAttestationsToForkChoiceStore(ctx, interfaces.WrappedPhase0SignedBeaconBlock(block).Block(), r, beaconState))

 	assert.Equal(t, false, s.hasBlock(ctx, [32]byte{}), "Should not have block")
 	assert.Equal(t, true, s.hasBlock(ctx, r), "Should have block")
@@ -539,17 +452,15 @@ func TestServiceStop_SaveCachedBlocks(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		cfg:            &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		cfg:            &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 		ctx:            ctx,
 		cancel:         cancel,
-		initSyncBlocks: make(map[[32]byte]block.SignedBeaconBlock),
+		initSyncBlocks: make(map[[32]byte]interfaces.SignedBeaconBlock),
 	}
-	b := util.NewBeaconBlock()
-	r, err := b.Block.HashTreeRoot()
+	block := testutil.NewBeaconBlock()
+	r, err := block.Block.HashTreeRoot()
 	require.NoError(t, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	s.saveInitSyncBlock(r, wsb)
+	s.saveInitSyncBlock(r, interfaces.WrappedPhase0SignedBeaconBlock(block))
 	require.NoError(t, s.Stop())
 	require.Equal(t, true, s.cfg.BeaconDB.HasBlock(ctx, r))
 }
@@ -560,7 +471,7 @@ func TestProcessChainStartTime_ReceivedFeed(t *testing.T) {
 	stateChannel := make(chan *feed.Event, 1)
 	stateSub := service.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
 	defer stateSub.Unsubscribe()
-	service.onPowchainStart(context.Background(), time.Now())
+	service.processChainStartTime(context.Background(), time.Now())

 	stateEvent := <-stateChannel
 	require.Equal(t, int(stateEvent.Type), statefeed.Initialized)
@@ -572,13 +483,11 @@ func BenchmarkHasBlockDB(b *testing.B) {
 	beaconDB := testDB.SetupDB(b)
 	ctx := context.Background()
 	s := &Service{
-		cfg: &config{BeaconDB: beaconDB},
+		cfg: &Config{BeaconDB: beaconDB},
 	}
-	blk := util.NewBeaconBlock()
-	wsb, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(b, err)
-	require.NoError(b, s.cfg.BeaconDB.SaveBlock(ctx, wsb))
-	r, err := blk.Block.HashTreeRoot()
+	block := testutil.NewBeaconBlock()
+	require.NoError(b, s.cfg.BeaconDB.SaveBlock(ctx, interfaces.WrappedPhase0SignedBeaconBlock(block)))
+	r, err := block.Block.HashTreeRoot()
 	require.NoError(b, err)

 	b.ResetTimer()
@@ -587,46 +496,20 @@ func BenchmarkHasBlockDB(b *testing.B) {
 	}
 }

-func BenchmarkHasBlockForkChoiceStore_ProtoArray(b *testing.B) {
+func BenchmarkHasBlockForkChoiceStore(b *testing.B) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(b)
 	s := &Service{
-		cfg:   &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
-		store: &store.Store{},
+		cfg:              &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
+		finalizedCheckpt: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash[:]})
-	blk := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
-	r, err := blk.Block.HashTreeRoot()
+	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
+	r, err := block.Block.HashTreeRoot()
 	require.NoError(b, err)
-	bs := &ethpb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}}
-	beaconState, err := v1.InitializeFromProto(bs)
+	bs := &pb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}}
+	beaconState, err := stateV0.InitializeFromProto(bs)
 	require.NoError(b, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(b, err)
-	require.NoError(b, s.insertBlockAndAttestationsToForkChoiceStore(ctx, wsb.Block(), r, beaconState))
-
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		require.Equal(b, true, s.cfg.ForkChoiceStore.HasNode(r), "Block is not in fork choice store")
-	}
-}
-func BenchmarkHasBlockForkChoiceStore_DoublyLinkedTree(b *testing.B) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(b)
-	s := &Service{
-		cfg:   &config{ForkChoiceStore: doublylinkedtree.New(0, 0), BeaconDB: beaconDB},
-		store: &store.Store{},
-	}
-	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash[:]})
-	blk := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
-	r, err := blk.Block.HashTreeRoot()
-	require.NoError(b, err)
-	bs := &ethpb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}}
-	beaconState, err := v1.InitializeFromProto(bs)
-	require.NoError(b, err)
-	wsb, err := wrapper.WrappedSignedBeaconBlock(blk)
-	require.NoError(b, err)
-	require.NoError(b, s.insertBlockAndAttestationsToForkChoiceStore(ctx, wsb.Block(), r, beaconState))
+	require.NoError(b, s.insertBlockAndAttestationsToForkChoiceStore(ctx, interfaces.WrappedPhase0SignedBeaconBlock(block).Block(), r, beaconState))

 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
--- a/beacon-chain/blockchain/state_balance_cache.go
+++ b/beacon-chain/blockchain/state_balance_cache.go
@@ -1,83 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"errors"
-	"sync"
-
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/time"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-)
-
-var errNilStateFromStategen = errors.New("justified state can't be nil")
-
-type stateBalanceCache struct {
-	sync.Mutex
-	balances []uint64
-	root     [32]byte
-	stateGen stateByRooter
-}
-
-type stateByRooter interface {
-	StateByRoot(context.Context, [32]byte) (state.BeaconState, error)
-}
-
-// newStateBalanceCache exists to remind us that stateBalanceCache needs a state gen
-// to avoid nil pointer bugs when updating the cache in the read path (get())
-func newStateBalanceCache(sg *stategen.State) (*stateBalanceCache, error) {
-	if sg == nil {
-		return nil, errors.New("can't initialize state balance cache without stategen")
-	}
-	return &stateBalanceCache{stateGen: sg}, nil
-}
-
-// update is called by get() when the requested root doesn't match
-// the previously read value. This cache assumes we only want to cache one
-// set of balances for a single root (the current justified root).
-//
-// warning: this is not thread-safe on its own, relies on get() for locking
-func (c *stateBalanceCache) update(ctx context.Context, justifiedRoot [32]byte) ([]uint64, error) {
-	stateBalanceCacheMiss.Inc()
-	justifiedState, err := c.stateGen.StateByRoot(ctx, justifiedRoot)
-	if err != nil {
-		return nil, err
-	}
-	if justifiedState == nil || justifiedState.IsNil() {
-		return nil, errNilStateFromStategen
-	}
-	epoch := time.CurrentEpoch(justifiedState)
-
-	justifiedBalances := make([]uint64, justifiedState.NumValidators())
-	var balanceAccumulator = func(idx int, val state.ReadOnlyValidator) error {
-		if helpers.IsActiveValidatorUsingTrie(val, epoch) {
-			justifiedBalances[idx] = val.EffectiveBalance()
-		} else {
-			justifiedBalances[idx] = 0
-		}
-		return nil
-	}
-	if err := justifiedState.ReadFromEveryValidator(balanceAccumulator); err != nil {
-		return nil, err
-	}
-
-	c.balances = justifiedBalances
-	c.root = justifiedRoot
-	return c.balances, nil
-}
-
-// getBalances takes an explicit justifiedRoot so it can invalidate the singleton cache key
-// when the justified root changes, and takes a context so that the long-running stategen
-// read path can connect to the upstream cancellation/timeout chain.
-func (c *stateBalanceCache) get(ctx context.Context, justifiedRoot [32]byte) ([]uint64, error) {
-	c.Lock()
-	defer c.Unlock()
-
-	if justifiedRoot != [32]byte{} && justifiedRoot == c.root {
-		stateBalanceCacheHit.Inc()
-		return c.balances, nil
-	}
-
-	return c.update(ctx, justifiedRoot)
-}
--- a/beacon-chain/blockchain/state_balance_cache_test.go
+++ b/beacon-chain/blockchain/state_balance_cache_test.go
@@ -1,227 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"encoding/binary"
-	"errors"
-	"testing"
-
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	v2 "github.com/prysmaticlabs/prysm/beacon-chain/state/v2"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/time/slots"
-)
-
-type testStateOpt func(*ethpb.BeaconStateAltair)
-
-func testStateWithValidators(v []*ethpb.Validator) testStateOpt {
-	return func(a *ethpb.BeaconStateAltair) {
-		a.Validators = v
-	}
-}
-
-func testStateWithSlot(slot types.Slot) testStateOpt {
-	return func(a *ethpb.BeaconStateAltair) {
-		a.Slot = slot
-	}
-}
-
-func testStateFixture(opts ...testStateOpt) state.BeaconState {
-	a := &ethpb.BeaconStateAltair{}
-	for _, o := range opts {
-		o(a)
-	}
-	s, _ := v2.InitializeFromProtoUnsafe(a)
-	return s
-}
-
-func generateTestValidators(count int, opts ...func(*ethpb.Validator)) []*ethpb.Validator {
-	vs := make([]*ethpb.Validator, count)
-	var i uint32 = 0
-	for ; i < uint32(count); i++ {
-		pk := make([]byte, 48)
-		binary.LittleEndian.PutUint32(pk, i)
-		v := &ethpb.Validator{PublicKey: pk}
-		for _, o := range opts {
-			o(v)
-		}
-		vs[i] = v
-	}
-	return vs
-}
-
-func oddValidatorsExpired(currentSlot types.Slot) func(*ethpb.Validator) {
-	return func(v *ethpb.Validator) {
-		pki := binary.LittleEndian.Uint64(v.PublicKey)
-		if pki%2 == 0 {
-			v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-		} else {
-			v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) - 1)
-		}
-	}
-}
-
-func oddValidatorsQueued(currentSlot types.Slot) func(*ethpb.Validator) {
-	return func(v *ethpb.Validator) {
-		v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-		pki := binary.LittleEndian.Uint64(v.PublicKey)
-		if pki%2 == 0 {
-			v.ActivationEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) - 1)
-		} else {
-			v.ActivationEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-		}
-	}
-}
-
-func allValidatorsValid(currentSlot types.Slot) func(*ethpb.Validator) {
-	return func(v *ethpb.Validator) {
-		v.ActivationEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) - 1)
-		v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-	}
-}
-
-func balanceIsKeyTimes2(v *ethpb.Validator) {
-	pki := binary.LittleEndian.Uint64(v.PublicKey)
-	v.EffectiveBalance = uint64(pki) * 2
-}
-
-func testHalfExpiredValidators() ([]*ethpb.Validator, []uint64) {
-	balances := []uint64{0, 0, 4, 0, 8, 0, 12, 0, 16, 0}
-	return generateTestValidators(10,
-		oddValidatorsExpired(types.Slot(99)),
-		balanceIsKeyTimes2), balances
-}
-
-func testHalfQueuedValidators() ([]*ethpb.Validator, []uint64) {
-	balances := []uint64{0, 0, 4, 0, 8, 0, 12, 0, 16, 0}
-	return generateTestValidators(10,
-		oddValidatorsQueued(types.Slot(99)),
-		balanceIsKeyTimes2), balances
-}
-
-func testAllValidValidators() ([]*ethpb.Validator, []uint64) {
-	balances := []uint64{0, 2, 4, 6, 8, 10, 12, 14, 16, 18}
-	return generateTestValidators(10,
-		allValidatorsValid(types.Slot(99)),
-		balanceIsKeyTimes2), balances
-}
-
-func TestStateBalanceCache(t *testing.T) {
-	type sbcTestCase struct {
-		err      error
-		root     [32]byte
-		sbc      *stateBalanceCache
-		balances []uint64
-		name     string
-	}
-	sentinelCacheMiss := errors.New("Cache missed, as expected!")
-	sentinelBalances := []uint64{1, 2, 3, 4, 5}
-	halfExpiredValidators, halfExpiredBalances := testHalfExpiredValidators()
-	halfQueuedValidators, halfQueuedBalances := testHalfQueuedValidators()
-	allValidValidators, allValidBalances := testAllValidValidators()
-	cases := []sbcTestCase{
-		{
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			balances: sentinelBalances,
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					err: sentinelCacheMiss,
-				},
-				root:     bytesutil.ToBytes32([]byte{'A'}),
-				balances: sentinelBalances,
-			},
-			name: "cache hit",
-		},
-		// this works by using a staterooter that returns a known error
-		// so really we're testing the miss by making sure stategen got called
-		// this also tells us stategen errors are propagated
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					err: sentinelCacheMiss,
-				},
-				root: bytesutil.ToBytes32([]byte{'B'}),
-			},
-			err:  sentinelCacheMiss,
-			root: bytesutil.ToBytes32([]byte{'A'}),
-			name: "cache miss",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{},
-				root:     bytesutil.ToBytes32([]byte{'B'}),
-			},
-			err:  errNilStateFromStategen,
-			root: bytesutil.ToBytes32([]byte{'A'}),
-			name: "error for nil state upon cache miss",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(halfExpiredValidators)),
-				},
-			},
-			balances: halfExpiredBalances,
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			name:     "test filtering by exit epoch",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(halfQueuedValidators)),
-				},
-			},
-			balances: halfQueuedBalances,
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			name:     "test filtering by activation epoch",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(allValidValidators)),
-				},
-			},
-			balances: allValidBalances,
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			name:     "happy path",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(allValidValidators)),
-				},
-			},
-			balances: allValidBalances,
-			root:     [32]byte{},
-			name:     "zero root",
-		},
-	}
-	ctx := context.Background()
-	for _, c := range cases {
-		t.Run(c.name, func(t *testing.T) {
-			cache := c.sbc
-			cacheRootStart := cache.root
-			b, err := cache.get(ctx, c.root)
-			require.ErrorIs(t, err, c.err)
-			require.DeepEqual(t, c.balances, b)
-			if c.err != nil {
-				// if there was an error somewhere, the root should not have changed (unless it already matched)
-				require.Equal(t, cacheRootStart, cache.root)
-			} else {
-				// when successful, the cache should always end with a root matching the request
-				require.Equal(t, c.root, cache.root)
-			}
-		})
-	}
-}
--- a/beacon-chain/blockchain/store/BUILD.bazel
+++ b/beacon-chain/blockchain/store/BUILD.bazel
@@ -1,27 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "doc.go",
-        "new.go",
-        "setter_getter.go",
-        "type.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/store",
-    visibility = ["//beacon-chain:__subpackages__"],
-    deps = ["//proto/prysm/v1alpha1:go_default_library"],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = [
-        "new_test.go",
-        "setter_getter_test.go",
-    ],
-    embed = [":go_default_library"],
-    deps = [
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//testing/require:go_default_library",
-    ],
-)
--- a/beacon-chain/blockchain/store/doc.go
+++ b/beacon-chain/blockchain/store/doc.go
@@ -1,4 +0,0 @@
-// Package store implements the store object defined in the phase0 fork choice spec.
-// It serves as a helpful middleware layer in between blockchain pkg and fork choice protoarray pkg.
-// All the getters and setters are concurrent thread safe
-package store
--- a/beacon-chain/blockchain/store/new.go
+++ b/beacon-chain/blockchain/store/new.go
@@ -1,15 +0,0 @@
-package store
-
-import (
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-)
-
-func New(justifiedCheckpt *ethpb.Checkpoint, finalizedCheckpt *ethpb.Checkpoint) *Store {
-	return &Store{
-		justifiedCheckpt:     justifiedCheckpt,
-		prevJustifiedCheckpt: justifiedCheckpt,
-		bestJustifiedCheckpt: justifiedCheckpt,
-		finalizedCheckpt:     finalizedCheckpt,
-		prevFinalizedCheckpt: finalizedCheckpt,
-	}
-}
--- a/beacon-chain/blockchain/store/new_test.go
+++ b/beacon-chain/blockchain/store/new_test.go
@@ -1,25 +0,0 @@
-package store
-
-import (
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-func TestNew(t *testing.T) {
-	j := &ethpb.Checkpoint{
-		Epoch: 0,
-		Root:  []byte("hi"),
-	}
-	f := &ethpb.Checkpoint{
-		Epoch: 0,
-		Root:  []byte("hello"),
-	}
-	s := New(j, f)
-	require.DeepSSZEqual(t, s.JustifiedCheckpt(), j)
-	require.DeepSSZEqual(t, s.BestJustifiedCheckpt(), j)
-	require.DeepSSZEqual(t, s.PrevJustifiedCheckpt(), j)
-	require.DeepSSZEqual(t, s.FinalizedCheckpt(), f)
-	require.DeepSSZEqual(t, s.PrevFinalizedCheckpt(), f)
-}
--- a/beacon-chain/blockchain/store/setter_getter.go
+++ b/beacon-chain/blockchain/store/setter_getter.go
@@ -1,73 +0,0 @@
-package store
-
-import ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-
-// PrevJustifiedCheckpt returns the previous justified checkpoint in the Store.
-func (s *Store) PrevJustifiedCheckpt() *ethpb.Checkpoint {
-	s.RLock()
-	defer s.RUnlock()
-	return s.prevJustifiedCheckpt
-}
-
-// BestJustifiedCheckpt returns the best justified checkpoint in the Store.
-func (s *Store) BestJustifiedCheckpt() *ethpb.Checkpoint {
-	s.RLock()
-	defer s.RUnlock()
-	return s.bestJustifiedCheckpt
-}
-
-// JustifiedCheckpt returns the justified checkpoint in the Store.
-func (s *Store) JustifiedCheckpt() *ethpb.Checkpoint {
-	s.RLock()
-	defer s.RUnlock()
-	return s.justifiedCheckpt
-}
-
-// PrevFinalizedCheckpt returns the previous finalized checkpoint in the Store.
-func (s *Store) PrevFinalizedCheckpt() *ethpb.Checkpoint {
-	s.RLock()
-	defer s.RUnlock()
-	return s.prevFinalizedCheckpt
-}
-
-// FinalizedCheckpt returns the finalized checkpoint in the Store.
-func (s *Store) FinalizedCheckpt() *ethpb.Checkpoint {
-	s.RLock()
-	defer s.RUnlock()
-	return s.finalizedCheckpt
-}
-
-// SetPrevJustifiedCheckpt sets the previous justified checkpoint in the Store.
-func (s *Store) SetPrevJustifiedCheckpt(cp *ethpb.Checkpoint) {
-	s.Lock()
-	defer s.Unlock()
-	s.prevJustifiedCheckpt = cp
-}
-
-// SetBestJustifiedCheckpt sets the best justified checkpoint in the Store.
-func (s *Store) SetBestJustifiedCheckpt(cp *ethpb.Checkpoint) {
-	s.Lock()
-	defer s.Unlock()
-	s.bestJustifiedCheckpt = cp
-}
-
-// SetJustifiedCheckpt sets the justified checkpoint in the Store.
-func (s *Store) SetJustifiedCheckpt(cp *ethpb.Checkpoint) {
-	s.Lock()
-	defer s.Unlock()
-	s.justifiedCheckpt = cp
-}
-
-// SetFinalizedCheckpt sets the finalized checkpoint in the Store.
-func (s *Store) SetFinalizedCheckpt(cp *ethpb.Checkpoint) {
-	s.Lock()
-	defer s.Unlock()
-	s.finalizedCheckpt = cp
-}
-
-// SetPrevFinalizedCheckpt sets the previous finalized checkpoint in the Store.
-func (s *Store) SetPrevFinalizedCheckpt(cp *ethpb.Checkpoint) {
-	s.Lock()
-	defer s.Unlock()
-	s.prevFinalizedCheckpt = cp
-}
--- a/beacon-chain/blockchain/store/setter_getter_test.go
+++ b/beacon-chain/blockchain/store/setter_getter_test.go
@@ -1,53 +0,0 @@
-package store
-
-import (
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-func Test_store_PrevJustifiedCheckpt(t *testing.T) {
-	s := &Store{}
-	var cp *ethpb.Checkpoint
-	require.Equal(t, cp, s.PrevJustifiedCheckpt())
-	cp = &ethpb.Checkpoint{Epoch: 1, Root: []byte{'a'}}
-	s.SetPrevJustifiedCheckpt(cp)
-	require.Equal(t, cp, s.PrevJustifiedCheckpt())
-}
-
-func Test_store_BestJustifiedCheckpt(t *testing.T) {
-	s := &Store{}
-	var cp *ethpb.Checkpoint
-	require.Equal(t, cp, s.BestJustifiedCheckpt())
-	cp = &ethpb.Checkpoint{Epoch: 1, Root: []byte{'a'}}
-	s.SetBestJustifiedCheckpt(cp)
-	require.Equal(t, cp, s.BestJustifiedCheckpt())
-}
-
-func Test_store_JustifiedCheckpt(t *testing.T) {
-	s := &Store{}
-	var cp *ethpb.Checkpoint
-	require.Equal(t, cp, s.JustifiedCheckpt())
-	cp = &ethpb.Checkpoint{Epoch: 1, Root: []byte{'a'}}
-	s.SetJustifiedCheckpt(cp)
-	require.Equal(t, cp, s.JustifiedCheckpt())
-}
-
-func Test_store_FinalizedCheckpt(t *testing.T) {
-	s := &Store{}
-	var cp *ethpb.Checkpoint
-	require.Equal(t, cp, s.FinalizedCheckpt())
-	cp = &ethpb.Checkpoint{Epoch: 1, Root: []byte{'a'}}
-	s.SetFinalizedCheckpt(cp)
-	require.Equal(t, cp, s.FinalizedCheckpt())
-}
-
-func Test_store_PrevFinalizedCheckpt(t *testing.T) {
-	s := &Store{}
-	var cp *ethpb.Checkpoint
-	require.Equal(t, cp, s.PrevFinalizedCheckpt())
-	cp = &ethpb.Checkpoint{Epoch: 1, Root: []byte{'a'}}
-	s.SetPrevFinalizedCheckpt(cp)
-	require.Equal(t, cp, s.PrevFinalizedCheckpt())
-}
--- a/beacon-chain/blockchain/store/type.go
+++ b/beacon-chain/blockchain/store/type.go
@@ -1,28 +0,0 @@
-package store
-
-import (
-	"sync"
-
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-)
-
-// Store is defined in the fork choice consensus spec for tracking current time and various versions of checkpoints.
-//
-// Spec code:
-// class Store(object):
-//    time: uint64
-//    genesis_time: uint64
-//    justified_checkpoint: Checkpoint
-//    finalized_checkpoint: Checkpoint
-//    best_justified_checkpoint: Checkpoint
-//    proposerBoostRoot: Root
-type Store struct {
-	justifiedCheckpt     *ethpb.Checkpoint
-	finalizedCheckpt     *ethpb.Checkpoint
-	bestJustifiedCheckpt *ethpb.Checkpoint
-	sync.RWMutex
-	// These are not part of the consensus spec, but we do use them to return gRPC API requests.
-	// TODO(10094): Consider removing in v3.
-	prevFinalizedCheckpt *ethpb.Checkpoint
-	prevJustifiedCheckpt *ethpb.Checkpoint
-}
--- a/beacon-chain/blockchain/testing/BUILD.bazel
+++ b/beacon-chain/blockchain/testing/BUILD.bazel
@@ -7,10 +7,9 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing",
    visibility = [
        "//beacon-chain:__subpackages__",
-        "//testing:__subpackages__",
+        "//fuzz:__pkg__",
    ],
    deps = [
-        "//async/event:go_default_library",
        "//beacon-chain/core/epoch/precompute:go_default_library",
        "//beacon-chain/core/feed:go_default_library",
        "//beacon-chain/core/feed/block:go_default_library",
@@ -18,13 +17,15 @@ go_library(
        "//beacon-chain/core/feed/state:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
        "//beacon-chain/db:go_default_library",
-        "//beacon-chain/forkchoice:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//config/fieldparams:go_default_library",
-        "//config/params:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//proto/prysm/v1alpha1/block:go_default_library",
+        "//beacon-chain/forkchoice/protoarray:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
+        "//proto/beacon/p2p/v1:go_default_library",
+        "//proto/eth/v1alpha1:go_default_library",
+        "//shared/bytesutil:go_default_library",
+        "//shared/event:go_default_library",
+        "//shared/interfaces:go_default_library",
+        "//shared/params:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
--- a/beacon-chain/blockchain/testing/mock.go
+++ b/beacon-chain/blockchain/testing/mock.go
@@ -10,7 +10,6 @@ import (

 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/async/event"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	blockfeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/block"
@@ -18,55 +17,41 @@ import (
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/event"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/sirupsen/logrus"
 )

-var ErrNilState = errors.New("nil state")
-
 // ChainService defines the mock interface for testing
 type ChainService struct {
-	Optimistic                  bool
-	ValidAttestation            bool
-	ValidatorsRoot              [32]byte
-	PublicKey                   [fieldparams.BLSPubkeyLength]byte
+	State                       iface.BeaconState
+	Root                        []byte
+	Block                       interfaces.SignedBeaconBlock
 	FinalizedCheckPoint         *ethpb.Checkpoint
 	CurrentJustifiedCheckPoint  *ethpb.Checkpoint
 	PreviousJustifiedCheckPoint *ethpb.Checkpoint
-	Slot                        *types.Slot // Pointer because 0 is a useful value, so checking against it can be incorrect.
+	BlocksReceived              []interfaces.SignedBeaconBlock
 	Balance                     *precompute.Balance
+	Genesis                     time.Time
+	ValidatorsRoot              [32]byte
 	CanonicalRoots              map[[32]byte]bool
-	Fork                        *ethpb.Fork
+	Fork                        *pb.Fork
 	ETH1Data                    *ethpb.Eth1Data
-	InitSyncBlockRoots          map[[32]byte]bool
 	DB                          db.Database
-	State                       state.BeaconState
-	Block                       block.SignedBeaconBlock
-	VerifyBlkDescendantErr      error
 	stateNotifier               statefeed.Notifier
-	BlocksReceived              []block.SignedBeaconBlock
-	SyncCommitteeIndices        []types.CommitteeIndex
 	blockNotifier               blockfeed.Notifier
 	opNotifier                  opfeed.Notifier
-	Root                        []byte
-	SyncCommitteeDomain         []byte
-	SyncSelectionProofDomain    []byte
-	SyncContributionProofDomain []byte
-	SyncCommitteePubkeys        [][]byte
-	Genesis                     time.Time
-	ForkChoiceStore             forkchoice.ForkChoicer
-	ReceiveBlockMockErr         error
-}
-
-// ForkChoicer mocks the same method in the chain service
-func (s *ChainService) ForkChoicer() forkchoice.ForkChoicer {
-	return s.ForkChoiceStore
+	ValidAttestation            bool
+	ForkChoiceStore             *protoarray.Store
+	VerifyBlkDescendantErr      error
+	Slot                        *types.Slot // Pointer because 0 is a useful value, so checking against it can be incorrect.
 }

 // StateNotifier mocks the same method in the chain service.
@@ -165,9 +150,9 @@ func (mon *MockOperationNotifier) OperationFeed() *event.Feed {
 }

 // ReceiveBlockInitialSync mocks ReceiveBlockInitialSync method in chain service.
-func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block block.SignedBeaconBlock, _ [32]byte) error {
+func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block interfaces.SignedBeaconBlock, _ [32]byte) error {
 	if s.State == nil {
-		return ErrNilState
+		s.State = &stateV0.BeaconState{}
 	}
 	if !bytes.Equal(s.Root, block.Block().ParentRoot()) {
 		return errors.Errorf("wanted %#x but got %#x", s.Root, block.Block().ParentRoot())
@@ -192,41 +177,38 @@ func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block block.
 }

 // ReceiveBlockBatch processes blocks in batches from initial-sync.
-func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []block.SignedBeaconBlock, _ [][32]byte) error {
+func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []interfaces.SignedBeaconBlock, _ [][32]byte) error {
 	if s.State == nil {
-		return ErrNilState
+		s.State = &stateV0.BeaconState{}
 	}
-	for _, b := range blks {
-		if !bytes.Equal(s.Root, b.Block().ParentRoot()) {
-			return errors.Errorf("wanted %#x but got %#x", s.Root, b.Block().ParentRoot())
+	for _, block := range blks {
+		if !bytes.Equal(s.Root, block.Block().ParentRoot()) {
+			return errors.Errorf("wanted %#x but got %#x", s.Root, block.Block().ParentRoot())
 		}
-		if err := s.State.SetSlot(b.Block().Slot()); err != nil {
+		if err := s.State.SetSlot(block.Block().Slot()); err != nil {
 			return err
 		}
-		s.BlocksReceived = append(s.BlocksReceived, b)
-		signingRoot, err := b.Block().HashTreeRoot()
+		s.BlocksReceived = append(s.BlocksReceived, block)
+		signingRoot, err := block.Block().HashTreeRoot()
 		if err != nil {
 			return err
 		}
 		if s.DB != nil {
-			if err := s.DB.SaveBlock(ctx, b); err != nil {
+			if err := s.DB.SaveBlock(ctx, block); err != nil {
 				return err
 			}
-			logrus.Infof("Saved block with root: %#x at slot %d", signingRoot, b.Block().Slot())
+			logrus.Infof("Saved block with root: %#x at slot %d", signingRoot, block.Block().Slot())
 		}
 		s.Root = signingRoot[:]
-		s.Block = b
+		s.Block = block
 	}
 	return nil
 }

 // ReceiveBlock mocks ReceiveBlock method in chain service.
-func (s *ChainService) ReceiveBlock(ctx context.Context, block block.SignedBeaconBlock, _ [32]byte) error {
-	if s.ReceiveBlockMockErr != nil {
-		return s.ReceiveBlockMockErr
-	}
+func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.SignedBeaconBlock, _ [32]byte) error {
 	if s.State == nil {
-		return ErrNilState
+		s.State = &stateV0.BeaconState{}
 	}
 	if !bytes.Equal(s.Root, block.Block().ParentRoot()) {
 		return errors.Errorf("wanted %#x but got %#x", s.Root, block.Block().ParentRoot())
@@ -267,17 +249,17 @@ func (s *ChainService) HeadRoot(_ context.Context) ([]byte, error) {
 }

 // HeadBlock mocks HeadBlock method in chain service.
-func (s *ChainService) HeadBlock(context.Context) (block.SignedBeaconBlock, error) {
+func (s *ChainService) HeadBlock(context.Context) (interfaces.SignedBeaconBlock, error) {
 	return s.Block, nil
 }

 // HeadState mocks HeadState method in chain service.
-func (s *ChainService) HeadState(context.Context) (state.BeaconState, error) {
+func (s *ChainService) HeadState(context.Context) (iface.BeaconState, error) {
 	return s.State, nil
 }

 // CurrentFork mocks HeadState method in chain service.
-func (s *ChainService) CurrentFork() *ethpb.Fork {
+func (s *ChainService) CurrentFork() *pb.Fork {
 	return s.Fork
 }

@@ -297,26 +279,26 @@ func (s *ChainService) PreviousJustifiedCheckpt() *ethpb.Checkpoint {
 }

 // ReceiveAttestation mocks ReceiveAttestation method in chain service.
-func (_ *ChainService) ReceiveAttestation(_ context.Context, _ *ethpb.Attestation) error {
+func (s *ChainService) ReceiveAttestation(_ context.Context, _ *ethpb.Attestation) error {
 	return nil
 }

 // ReceiveAttestationNoPubsub mocks ReceiveAttestationNoPubsub method in chain service.
-func (_ *ChainService) ReceiveAttestationNoPubsub(context.Context, *ethpb.Attestation) error {
+func (s *ChainService) ReceiveAttestationNoPubsub(context.Context, *ethpb.Attestation) error {
 	return nil
 }

-// AttestationTargetState mocks AttestationTargetState method in chain service.
-func (s *ChainService) AttestationTargetState(_ context.Context, _ *ethpb.Checkpoint) (state.BeaconState, error) {
+// AttestationPreState mocks AttestationPreState method in chain service.
+func (s *ChainService) AttestationPreState(_ context.Context, _ *ethpb.Attestation) (iface.BeaconState, error) {
 	return s.State, nil
 }

 // HeadValidatorsIndices mocks the same method in the chain service.
-func (s *ChainService) HeadValidatorsIndices(ctx context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error) {
+func (s *ChainService) HeadValidatorsIndices(_ context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error) {
 	if s.State == nil {
 		return []types.ValidatorIndex{}, nil
 	}
-	return helpers.ActiveValidatorIndices(ctx, s.State, epoch)
+	return helpers.ActiveValidatorIndices(s.State, epoch)
 }

 // HeadSeed mocks the same method in the chain service.
@@ -329,13 +311,18 @@ func (s *ChainService) HeadETH1Data() *ethpb.Eth1Data {
 	return s.ETH1Data
 }

+// ProtoArrayStore mocks the same method in the chain service.
+func (s *ChainService) ProtoArrayStore() *protoarray.Store {
+	return s.ForkChoiceStore
+}
+
 // GenesisTime mocks the same method in the chain service.
 func (s *ChainService) GenesisTime() time.Time {
 	return s.Genesis
 }

-// GenesisValidatorsRoot mocks the same method in the chain service.
-func (s *ChainService) GenesisValidatorsRoot() [32]byte {
+// GenesisValidatorRoot mocks the same method in the chain service.
+func (s *ChainService) GenesisValidatorRoot() [32]byte {
 	return s.ValidatorsRoot
 }

@@ -368,15 +355,12 @@ func (s *ChainService) IsCanonical(_ context.Context, r [32]byte) (bool, error)
 }

 // HasInitSyncBlock mocks the same method in the chain service.
-func (s *ChainService) HasInitSyncBlock(rt [32]byte) bool {
-	if s.InitSyncBlockRoots == nil {
-		return false
-	}
-	return s.InitSyncBlockRoots[rt]
+func (s *ChainService) HasInitSyncBlock(_ [32]byte) bool {
+	return false
 }

-// HeadGenesisValidatorsRoot mocks HeadGenesisValidatorsRoot method in chain service.
-func (_ *ChainService) HeadGenesisValidatorsRoot() [32]byte {
+// HeadGenesisValidatorRoot mocks HeadGenesisValidatorRoot method in chain service.
+func (s *ChainService) HeadGenesisValidatorRoot() [32]byte {
 	return [32]byte{}
 }

@@ -386,7 +370,7 @@ func (s *ChainService) VerifyBlkDescendant(_ context.Context, _ [32]byte) error
 }

 // VerifyLmdFfgConsistency mocks VerifyLmdFfgConsistency and always returns nil.
-func (_ *ChainService) VerifyLmdFfgConsistency(_ context.Context, a *ethpb.Attestation) error {
+func (s *ChainService) VerifyLmdFfgConsistency(_ context.Context, a *ethpb.Attestation) error {
 	if !bytes.Equal(a.Data.BeaconBlockRoot, a.Data.Target.Root) {
 		return errors.New("LMD and FFG miss matched")
 	}
@@ -402,55 +386,10 @@ func (s *ChainService) VerifyFinalizedConsistency(_ context.Context, r []byte) e
 }

 // ChainHeads mocks ChainHeads and always return nil.
-func (_ *ChainService) ChainHeads() ([][32]byte, []types.Slot) {
+func (s *ChainService) ChainHeads() ([][32]byte, []types.Slot) {
 	return [][32]byte{
 			bytesutil.ToBytes32(bytesutil.PadTo([]byte("foo"), 32)),
 			bytesutil.ToBytes32(bytesutil.PadTo([]byte("bar"), 32)),
 		},
 		[]types.Slot{0, 1}
 }
-
-// HeadPublicKeyToValidatorIndex mocks HeadPublicKeyToValidatorIndex and always return 0 and true.
-func (_ *ChainService) HeadPublicKeyToValidatorIndex(_ [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool) {
-	return 0, true
-}
-
-// HeadValidatorIndexToPublicKey mocks HeadValidatorIndexToPublicKey and always return empty and nil.
-func (s *ChainService) HeadValidatorIndexToPublicKey(_ context.Context, _ types.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error) {
-	return s.PublicKey, nil
-}
-
-// HeadSyncCommitteeIndices mocks HeadSyncCommitteeIndices and always return `HeadNextSyncCommitteeIndices`.
-func (s *ChainService) HeadSyncCommitteeIndices(_ context.Context, _ types.ValidatorIndex, _ types.Slot) ([]types.CommitteeIndex, error) {
-	return s.SyncCommitteeIndices, nil
-}
-
-// HeadSyncCommitteePubKeys mocks HeadSyncCommitteePubKeys and always return empty nil.
-func (s *ChainService) HeadSyncCommitteePubKeys(_ context.Context, _ types.Slot, _ types.CommitteeIndex) ([][]byte, error) {
-	return s.SyncCommitteePubkeys, nil
-}
-
-// HeadSyncCommitteeDomain mocks HeadSyncCommitteeDomain and always return empty nil.
-func (s *ChainService) HeadSyncCommitteeDomain(_ context.Context, _ types.Slot) ([]byte, error) {
-	return s.SyncCommitteeDomain, nil
-}
-
-// HeadSyncSelectionProofDomain mocks HeadSyncSelectionProofDomain and always return empty nil.
-func (s *ChainService) HeadSyncSelectionProofDomain(_ context.Context, _ types.Slot) ([]byte, error) {
-	return s.SyncSelectionProofDomain, nil
-}
-
-// HeadSyncContributionProofDomain mocks HeadSyncContributionProofDomain and always return empty nil.
-func (s *ChainService) HeadSyncContributionProofDomain(_ context.Context, _ types.Slot) ([]byte, error) {
-	return s.SyncContributionProofDomain, nil
-}
-
-// IsOptimistic mocks the same method in the chain service.
-func (s *ChainService) IsOptimistic(_ context.Context) (bool, error) {
-	return s.Optimistic, nil
-}
-
-// IsOptimisticForRoot mocks the same method in the chain service.
-func (s *ChainService) IsOptimisticForRoot(_ context.Context, _ [32]byte) (bool, error) {
-	return s.Optimistic, nil
-}
--- a/beacon-chain/blockchain/weak_subjectivity_checks.go
+++ b/beacon-chain/blockchain/weak_subjectivity_checks.go
@@ -4,97 +4,57 @@ import (
 	"context"
 	"fmt"

-	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )

-var errWSBlockNotFound = errors.New("weak subjectivity root not found in db")
-var errWSBlockNotFoundInEpoch = errors.New("weak subjectivity root not found in db within epoch")
-
-type weakSubjectivityDB interface {
-	HasBlock(ctx context.Context, blockRoot [32]byte) bool
-	BlockRoots(ctx context.Context, f *filters.QueryFilter) ([][32]byte, error)
-}
-
-type WeakSubjectivityVerifier struct {
-	enabled  bool
-	verified bool
-	root     [32]byte
-	epoch    types.Epoch
-	slot     types.Slot
-	db       weakSubjectivityDB
-}
-
-// NewWeakSubjectivityVerifier validates a checkpoint, and if valid, uses it to initialize a weak subjectivity verifier
-func NewWeakSubjectivityVerifier(wsc *ethpb.Checkpoint, db weakSubjectivityDB) (*WeakSubjectivityVerifier, error) {
-	// TODO(7342): Weak subjectivity checks are currently optional. When we require the flag to be specified
-	// per 7342, a nil checkpoint, zero-root or zero-epoch should all fail validation
-	// and return an error instead of creating a WeakSubjectivityVerifier that permits any chain history.
-	if wsc == nil || len(wsc.Root) == 0 || wsc.Epoch == 0 {
-		log.Warn("No valid weak subjectivity checkpoint specified, running without weak subjectivity verification")
-		return &WeakSubjectivityVerifier{
-			enabled: false,
-		}, nil
+// VerifyWeakSubjectivityRoot verifies the weak subjectivity root in the service struct.
+// Reference design: https://github.com/ethereum/eth2.0-specs/blob/master/specs/phase0/weak-subjectivity.md#weak-subjectivity-sync-procedure
+func (s *Service) VerifyWeakSubjectivityRoot(ctx context.Context) error {
+	// TODO(7342): Remove the following to fully use weak subjectivity in production.
+	if s.cfg.WeakSubjectivityCheckpt == nil || len(s.cfg.WeakSubjectivityCheckpt.Root) == 0 || s.cfg.WeakSubjectivityCheckpt.Epoch == 0 {
+		return nil
 	}
-	startSlot, err := slots.EpochStart(wsc.Epoch)
+
+	// Do nothing if the weak subjectivity has previously been verified,
+	// or weak subjectivity epoch is higher than last finalized epoch.
+	if s.wsVerified {
+		return nil
+	}
+	if s.cfg.WeakSubjectivityCheckpt.Epoch > s.finalizedCheckpt.Epoch {
+		return nil
+	}
+
+	r := bytesutil.ToBytes32(s.cfg.WeakSubjectivityCheckpt.Root)
+	log.Infof("Performing weak subjectivity check for root %#x in epoch %d", r, s.cfg.WeakSubjectivityCheckpt.Epoch)
+	// Save initial sync cached blocks to DB.
+	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+		return err
+	}
+	// A node should have the weak subjectivity block in the DB.
+	if !s.cfg.BeaconDB.HasBlock(ctx, r) {
+		return fmt.Errorf("node does not have root in DB: %#x", r)
+	}
+
+	startSlot, err := helpers.StartSlot(s.cfg.WeakSubjectivityCheckpt.Epoch)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	return &WeakSubjectivityVerifier{
-		enabled:  true,
-		verified: false,
-		root:     bytesutil.ToBytes32(wsc.Root),
-		epoch:    wsc.Epoch,
-		db:       db,
-		slot:     startSlot,
-	}, nil
-}
-
-// VerifyWeakSubjectivity verifies the weak subjectivity root in the service struct.
-// Reference design: https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/weak-subjectivity.md#weak-subjectivity-sync-procedure
-func (v *WeakSubjectivityVerifier) VerifyWeakSubjectivity(ctx context.Context, finalizedEpoch types.Epoch) error {
-	if v.verified || !v.enabled {
-		return nil
-	}
-
-	// Two conditions are described in the specs:
-	// IF epoch_number > store.finalized_checkpoint.epoch,
-	// then ASSERT during block sync that block with root block_root
-	// is in the sync path at epoch epoch_number. Emit descriptive critical error if this assert fails,
-	// then exit client process.
-	// we do not handle this case ^, because we can only blocks that have been processed / are currently
-	// in line for finalization, we don't have the ability to look ahead. so we only satisfy the following:
-	// IF epoch_number <= store.finalized_checkpoint.epoch,
-	// then ASSERT that the block in the canonical chain at epoch epoch_number has root block_root.
-	// Emit descriptive critical error if this assert fails, then exit client process.
-	if v.epoch > finalizedEpoch {
-		return nil
-	}
-	log.Infof("Performing weak subjectivity check for root %#x in epoch %d", v.root, v.epoch)
-
-	if !v.db.HasBlock(ctx, v.root) {
-		return errors.Wrap(errWSBlockNotFound, fmt.Sprintf("missing root %#x", v.root))
-	}
-	endSlot := v.slot + params.BeaconConfig().SlotsPerEpoch
-	filter := filters.NewFilter().SetStartSlot(v.slot).SetEndSlot(endSlot)
 	// A node should have the weak subjectivity block corresponds to the correct epoch in the DB.
-	log.Infof("Searching block roots for weak subjectivity root=%#x, between slots %d-%d", v.root, v.slot, endSlot)
-	roots, err := v.db.BlockRoots(ctx, filter)
+	filter := filters.NewFilter().SetStartSlot(startSlot).SetEndSlot(startSlot + params.BeaconConfig().SlotsPerEpoch)
+	roots, err := s.cfg.BeaconDB.BlockRoots(ctx, filter)
 	if err != nil {
-		return errors.Wrap(err, "error while retrieving block roots to verify weak subjectivity")
+		return err
 	}
 	for _, root := range roots {
-		if v.root == root {
-			log.Info("Weak subjectivity check has passed!!")
-			v.verified = true
+		if r == root {
+			log.Info("Weak subjectivity check has passed")
+			s.wsVerified = true
 			return nil
 		}
 	}

-	return errors.Wrap(errWSBlockNotFoundInEpoch, fmt.Sprintf("root=%#x, epoch=%d", v.root, v.epoch))
+	return fmt.Errorf("node does not have root in db corresponding to epoch: %#x %d", r, s.cfg.WeakSubjectivityCheckpt.Epoch)
 }
--- a/beacon-chain/blockchain/weak_subjectivity_checks_test.go
+++ b/beacon-chain/blockchain/weak_subjectivity_checks_test.go
@@ -4,87 +4,78 @@ import (
 	"context"
 	"testing"

-	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/blockchain/store"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-	"github.com/prysmaticlabs/prysm/time/slots"
+	ethpb "github.com/prysmaticlabs/prysm/proto/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/interfaces"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestService_VerifyWeakSubjectivityRoot(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)

-	b := util.NewBeaconBlock()
-	b.Block.Slot = 1792480
-	wsb, err := wrapper.WrappedSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(context.Background(), wsb))
+	b := testutil.NewBeaconBlock()
+	b.Block.Slot = 32
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), interfaces.WrappedPhase0SignedBeaconBlock(b)))
 	r, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-
-	blockEpoch := slots.ToEpoch(b.Block.Slot)
 	tests := []struct {
 		wsVerified     bool
-		disabled       bool
-		wantErr        error
+		wantErr        bool
 		checkpt        *ethpb.Checkpoint
 		finalizedEpoch types.Epoch
+		errString      string
 		name           string
 	}{
 		{
-			name:     "nil root and epoch",
-			disabled: true,
+			name:    "nil root and epoch",
+			wantErr: false,
+		},
+		{
+			name:           "already verified",
+			checkpt:        &ethpb.Checkpoint{Epoch: 2},
+			finalizedEpoch: 2,
+			wsVerified:     true,
+			wantErr:        false,
 		},
 		{
 			name:           "not yet to verify, ws epoch higher than finalized epoch",
-			checkpt:        &ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'a'}, 32), Epoch: blockEpoch},
-			finalizedEpoch: blockEpoch - 1,
+			checkpt:        &ethpb.Checkpoint{Epoch: 2},
+			finalizedEpoch: 1,
+			wantErr:        false,
 		},
 		{
 			name:           "can't find the block in DB",
-			checkpt:        &ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength), Epoch: 1},
-			finalizedEpoch: blockEpoch + 1,
-			wantErr:        errWSBlockNotFound,
+			checkpt:        &ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'a'}, 32), Epoch: 1},
+			finalizedEpoch: 3,
+			wantErr:        true,
+			errString:      "node does not have root in DB",
 		},
 		{
 			name:           "can't find the block corresponds to ws epoch in DB",
-			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: blockEpoch - 2}, // Root belongs in epoch 1.
-			finalizedEpoch: blockEpoch - 1,
-			wantErr:        errWSBlockNotFoundInEpoch,
+			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: 2}, // Root belongs in epoch 1.
+			finalizedEpoch: 3,
+			wantErr:        true,
+			errString:      "node does not have root in db corresponding to epoch",
 		},
 		{
 			name:           "can verify and pass",
-			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: blockEpoch},
-			finalizedEpoch: blockEpoch + 1,
-		},
-		{
-			name:           "equal epoch",
-			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: blockEpoch},
-			finalizedEpoch: blockEpoch,
+			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: 1},
+			finalizedEpoch: 3,
+			wantErr:        false,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			wv, err := NewWeakSubjectivityVerifier(tt.checkpt, beaconDB)
-			require.Equal(t, !tt.disabled, wv.enabled)
-			require.NoError(t, err)
 			s := &Service{
-				cfg:        &config{BeaconDB: beaconDB, WeakSubjectivityCheckpt: tt.checkpt},
-				store:      &store.Store{},
-				wsVerifier: wv,
+				cfg:              &Config{BeaconDB: beaconDB, WeakSubjectivityCheckpt: tt.checkpt},
+				wsVerified:       tt.wsVerified,
+				finalizedCheckpt: &ethpb.Checkpoint{Epoch: tt.finalizedEpoch},
 			}
-			s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: tt.finalizedEpoch})
-			err = s.wsVerifier.VerifyWeakSubjectivity(context.Background(), s.store.FinalizedCheckpt().Epoch)
-			if tt.wantErr == nil {
-				require.NoError(t, err)
-			} else {
-				require.Equal(t, true, errors.Is(err, tt.wantErr))
+			if err := s.VerifyWeakSubjectivityRoot(context.Background()); (err != nil) != tt.wantErr {
+				require.ErrorContains(t, tt.errString, err)
 			}
 		})
 	}
--- a/beacon-chain/cache/BUILD.bazel
+++ b/beacon-chain/cache/BUILD.bazel
@@ -1,48 +1,44 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+load("@prysm//tools/go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_test")

+# gazelle:exclude committee_disabled.go
+# gazelle:exclude proposer_indices_disabled.go
 go_library(
    name = "go_default_library",
    srcs = [
-        "active_balance.go",
-        "active_balance_disabled.go",  # keep
        "attestation_data.go",
        "checkpoint_state.go",
-        "committee.go",
-        "committee_disabled.go",  # keep
        "committees.go",
        "common.go",
        "doc.go",
-        "error.go",
-        "proposer_indices.go",
-        "proposer_indices_disabled.go",  # keep
        "proposer_indices_type.go",
        "skip_slot_cache.go",
        "subnet_ids.go",
-        "sync_committee.go",
-        "sync_committee_disabled.go",  # keep
-        "sync_committee_head_state.go",
-        "sync_subnet_ids.go",
-    ],
+    ] + select({
+        "//fuzz:fuzzing_enabled": [
+            "committee_disabled.go",
+            "proposer_indices_disabled.go",
+        ],
+        "//conditions:default": [
+            "committee.go",
+            "proposer_indices.go",
+        ],
+    }),
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/cache",
    visibility = [
        "//beacon-chain:__subpackages__",
+        "//fuzz:__pkg__",
        "//tools:__subpackages__",
    ],
    deps = [
-        "//beacon-chain/state:go_default_library",
-        "//cache/lru:go_default_library",
-        "//config/features:go_default_library",
-        "//config/params:go_default_library",
-        "//container/slice:go_default_library",
-        "//crypto/hash:go_default_library",
-        "//crypto/rand:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//math:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//runtime/version:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//proto/eth/v1alpha1:go_default_library",
+        "//shared/copyutil:go_default_library",
+        "//shared/hashutil:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/sliceutil:go_default_library",
        "@com_github_hashicorp_golang_lru//:go_default_library",
        "@com_github_patrickmn_go_cache//:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
@@ -55,7 +51,6 @@ go_test(
    name = "go_default_test",
    size = "small",
    srcs = [
-        "active_balance_test.go",
        "attestation_data_test.go",
        "cache_test.go",
        "checkpoint_state_test.go",
@@ -64,24 +59,17 @@ go_test(
        "proposer_indices_test.go",
        "skip_slot_cache_test.go",
        "subnet_ids_test.go",
-        "sync_committee_head_state_test.go",
-        "sync_committee_test.go",
-        "sync_subnet_ids_test.go",
    ],
    embed = [":go_default_library"],
    deps = [
-        "//beacon-chain/state:go_default_library",
-        "//beacon-chain/state/v1:go_default_library",
-        "//beacon-chain/state/v2:go_default_library",
-        "//beacon-chain/state/v3:go_default_library",
-        "//config/features:go_default_library",
-        "//config/fieldparams:go_default_library",
-        "//config/params:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-        "//testing/util:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
+        "//proto/beacon/p2p/v1:go_default_library",
+        "//proto/eth/v1alpha1:go_default_library",
+        "//shared/bytesutil:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
        "@com_github_google_gofuzz//:go_default_library",
        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@org_golang_google_protobuf//proto:go_default_library",
--- a/Show More
+++ b/Show More
@@ -1 +1 @@
 .0.0
 .7.0