revert delay

Merge branch 'develop' of https://github.com/prysmaticlabs/geth-sharding into fakeProposerBranch
increase time
2026-01-10 13:58:09 -05:00 · 2023-06-30 12:50:59 +08:00 · 2023-06-30 12:04:18 +08:00 · 2023-06-30 12:03:38 +08:00 · 2023-06-29 15:38:26 +00:00 · 2023-06-29 02:49:21 +00:00
668 changed files with 23731 additions and 12335 deletions
--- a/.bazelrc
+++ b/.bazelrc
@@ -3,6 +3,7 @@ import %workspace%/build/bazelrc/convenience.bazelrc
 import %workspace%/build/bazelrc/correctness.bazelrc
 import %workspace%/build/bazelrc/cross.bazelrc
 import %workspace%/build/bazelrc/debug.bazelrc
+import %workspace%/build/bazelrc/hermetic-cc.bazelrc
 import %workspace%/build/bazelrc/performance.bazelrc

 # E2E run with debug gotag
@@ -14,7 +15,7 @@ coverage --define=coverage_enabled=1
 # Stamp binaries with git information
 build --workspace_status_command=./hack/workspace_status.sh

-build --define blst_disabled=false
+build --define blst_disabled=false --define blst_modern=true
 run --define blst_disabled=false

 build:blst_disabled --define blst_disabled=true
@@ -27,30 +28,7 @@ build:minimal --@io_bazel_rules_go//go/config:tags=minimal
 build:release --compilation_mode=opt
 build:release --stamp

-# LLVM compiler for building C/C++ dependencies.
-build:llvm --define compiler=llvm
-build:llvm --copt -fno-sanitize=vptr,function
-build:llvm --linkopt -fno-sanitize=vptr,function
-# --incompatible_enable_cc_toolchain_resolution not needed after this issue is closed https://github.com/bazelbuild/bazel/issues/7260
-build:llvm --incompatible_enable_cc_toolchain_resolution
-
-build:asan --copt -fsanitize=address,undefined
-build:asan --copt -fno-omit-frame-pointer
-build:asan --linkopt -fsanitize=address,undefined
-build:asan --copt -fno-sanitize=vptr,function
-build:asan --linkopt -fno-sanitize=vptr,function
-build:asan --copt -DADDRESS_SANITIZER=1
-build:asan --copt -D__SANITIZE_ADDRESS__
-build:asan --linkopt -ldl
-
-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 binary with cgo symbolizer for debugging / profiling.
-build:cgo_symbolizer --config=llvm
 build:cgo_symbolizer --copt=-g
 build:cgo_symbolizer --define=USE_CGO_SYMBOLIZER=true
 build:cgo_symbolizer -c dbg
@@ -59,9 +37,13 @@ build:cgo_symbolizer --define=gotags=cgosymbolizer_enabled
 # toolchain build debug configs
 #------------------------------
 build:debug --sandbox_debug
-build:debug --toolchain_resolution_debug
+build:debug --toolchain_resolution_debug=".*"
 build:debug --verbose_failures
 build:debug -s

 # Set bazel gotag
 build --define gotags=bazel
+
+# Abseil requires c++14 or greater.
+build --cxxopt=-std=c++20
+build --host_cxxopt=-std=c++20
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-6.1.0
+6.2.1
--- a/.buildkite-bazelrc
+++ b/.buildkite-bazelrc
@@ -43,4 +43,12 @@ build --flaky_test_attempts=5

 # Better caching
 build:nostamp --nostamp
-build:nostamp --workspace_status_command=./hack/workspace_status_ci.sh
+
+# Build metadata
+build --build_metadata=ROLE=CI
+build --build_metadata=REPO_URL=https://github.com/prysmaticlabs/prysm.git
+build --workspace_status_command=./hack/workspace_status_ci.sh
+
+# Buildbuddy
+build --bes_results_url=https://app.buildbuddy.io/invocation/
+build --bes_backend=grpcs://remote.buildbuddy.io
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -26,14 +26,14 @@ jobs:
    steps:
      - name: Checkout
        uses: actions/checkout@v2
-      - name: Set up Go 1.19
+      - name: Set up Go 1.20
        uses: actions/setup-go@v3
        with:
-          go-version: 1.19
+          go-version: '1.20'
      - 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@v2.12.0
+          go install github.com/securego/gosec/v2/cmd/gosec@v2.15.0
          gosec -exclude=G307 -exclude-dir=crypto/bls/herumi ./...

  lint:
@@ -43,16 +43,16 @@ jobs:
      - name: Checkout
        uses: actions/checkout@v2

-      - name: Set up Go 1.19
+      - name: Set up Go 1.20
        uses: actions/setup-go@v3
        with:
-          go-version: 1.19
+          go-version: '1.20'
          id: go

      - name: Golangci-lint
        uses: golangci/golangci-lint-action@v3
        with:
-          version: v1.50.1
+          version: v1.52.2
          args: --config=.golangci.yml --out-${NO_FUTURE}format colored-line-number

  build:
@@ -62,7 +62,7 @@ jobs:
      - name: Set up Go 1.x
        uses: actions/setup-go@v2
        with:
-          go-version: 1.19
+          go-version: '1.20'
        id: go

      - name: Check out code into the Go module directory
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -17,6 +17,10 @@ linters:
    - errcheck
    - gosimple
    - gocognit
+    - dupword
+    - nilerr
+    - whitespace
+    - misspell

 linters-settings:
  gocognit:
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -3,7 +3,6 @@ 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("@bazel_skylib//rules:common_settings.bzl", "string_setting")

 prefix = "github.com/prysmaticlabs/prysm"
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,6 +1,6 @@
 # Contribution Guidelines

-Note: The latest and most up to date documenation can be found on our [docs portal](https://docs.prylabs.network/docs/contribute/contribution-guidelines).
+Note: The latest and most up-to-date documentation can be found on our [docs portal](https://docs.prylabs.network/docs/contribute/contribution-guidelines).

 Excited by our work and want to get involved in building out our sharding releases? Or maybe you haven't learned as much about the Ethereum protocol but are a savvy developer? 

@@ -10,9 +10,9 @@ You can explore our [Open Issues](https://github.com/prysmaticlabs/prysm/issues)

 **1. Set up Prysm following the instructions in README.md.**

-**2. Fork the prysm repo.**
+**2. Fork the Prysm repo.**

-Sign in to your Github account or create a new account if you do not have one already. Then navigate your browser to https://github.com/prysmaticlabs/prysm/. In the upper right hand corner of the page, click “fork”. This will create a copy of the Prysm repo in your account.
+Sign in to your GitHub account or create a new account if you do not have one already. Then navigate your browser to https://github.com/prysmaticlabs/prysm/. In the upper right hand corner of the page, click “fork”. This will create a copy of the Prysm repo in your account.

 **3. Create a local clone of Prysm.**

@@ -23,7 +23,7 @@ $ git clone https://github.com/prysmaticlabs/prysm.git
 $ cd $GOPATH/src/github.com/prysmaticlabs/prysm
 ```

-**4. Link your local clone to the fork on your Github repo.**
+**4. Link your local clone to the fork on your GitHub repo.**

 ```
 $ git remote add myprysmrepo https://github.com/<your_github_user_name>/prysm.git
@@ -68,7 +68,7 @@ $ go test <file_you_are_working_on>
 $ git add --all
 ```

-This command stages all of the files that you have changed. You can add individual files by specifying the file name or names and eliminating the “-- all”.
+This command stages all the files that you have changed. You can add individual files by specifying the file name or names and eliminating the “-- all”.

 **11. Commit the file or files.**

@@ -96,8 +96,7 @@ If there are conflicts between your edits and those made by others since you sta
 $ git status
 ```

-Open those files one at a time and you
-will see lines inserted by Git that identify the conflicts:
+Open those files one at a time, and you will see lines inserted by Git that identify the conflicts:

 ```
 <<<<<< HEAD
@@ -119,7 +118,7 @@ $ git push myrepo feature-in-progress-branch

 **15. Check to be sure your fork of the Prysm repo contains your feature branch with the latest edits.**

-Navigate to your fork of the repo on Github. On the upper left where the current branch is listed, change the branch to your feature-in-progress-branch. Open the files that you have worked on and check to make sure they include your changes.
+Navigate to your fork of the repo on GitHub. On the upper left where the current branch is listed, change the branch to your feature-in-progress-branch. Open the files that you have worked on and check to make sure they include your changes.

 **16. Create a pull request.**

@@ -151,7 +150,7 @@ pick 	hash 	fix a bug
 pick 	hash 	add a feature
 ```

-Replace the word pick with the word “squash” for every line but the first so you end with ….
+Replace the word pick with the word “squash” for every line but the first, so you end with ….

 ```
 pick    hash	do some work
@@ -178,7 +177,7 @@ We consider two types of contributions to our repo and categorize them as follow
 Anyone can become a part-time contributor and help out on implementing Ethereum consensus. 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
+-   Opening up GitHub issues to express interest in code to implement
 -   Opening up PRs referencing any open issue in the repo. PRs should include:
    -   Detailed context of what would be required for merge
    -   Tests that are consistent with how other tests are written in our implementation
@@ -188,12 +187,12 @@ Anyone can become a part-time contributor and help out on implementing Ethereum

 ### Core Contributors

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

 -   Stay up to date on the latest beacon chain specification
-   Monitor github issues and PR’s to make sure owner, labels, descriptions are correct
+-   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
+-   Participate in code review, ensure code quality is excellent, and ensure high code coverage
 -   Help with social media presence, write bi-weekly development update
 -   Represent Prysmatic Labs at events to help spread the word on scalability research and solutions

--- a/README.md
+++ b/README.md
@@ -4,14 +4,14 @@
 [![Go Report Card](https://goreportcard.com/badge/github.com/prysmaticlabs/prysm)](https://goreportcard.com/report/github.com/prysmaticlabs/prysm)
 [![Consensus_Spec_Version 1.3.0](https://img.shields.io/badge/Consensus%20Spec%20Version-v1.3.0-blue.svg)](https://github.com/ethereum/consensus-specs/tree/v1.3.0)
 [![Execution_API_Version 1.0.0-beta.2](https://img.shields.io/badge/Execution%20API%20Version-v1.0.0.beta.2-blue.svg)](https://github.com/ethereum/execution-apis/tree/v1.0.0-beta.2/src/engine)
-[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/CTYGPUJ)
+[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/prysmaticlabs)
 [![GitPOAP Badge](https://public-api.gitpoap.io/v1/repo/prysmaticlabs/prysm/badge)](https://www.gitpoap.io/gh/prysmaticlabs/prysm)

 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.

 ### Getting Started

-A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the [official documentation portal](https://docs.prylabs.network). If you still have questions, feel free to stop by our [Discord](https://discord.gg/CTYGPUJ).
+A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the [official documentation portal](https://docs.prylabs.network). If you still have questions, feel free to stop by our [Discord](https://discord.gg/prysmaticlabs).

 ### Staking on Mainnet

--- a/64
+++ b/64
@@ -16,27 +16,37 @@ load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")

 rules_pkg_dependencies()

+HERMETIC_CC_TOOLCHAIN_VERSION = "v2.0.0"
+
 http_archive(
-    name = "com_grail_bazel_toolchain",
-    sha256 = "b210fc8e58782ef171f428bfc850ed7179bdd805543ebd1aa144b9c93489134f",
-    strip_prefix = "bazel-toolchain-83e69ba9e4b4fdad0d1d057fcb87addf77c281c9",
-    urls = ["https://github.com/grailbio/bazel-toolchain/archive/83e69ba9e4b4fdad0d1d057fcb87addf77c281c9.tar.gz"],
+    name = "hermetic_cc_toolchain",
+    sha256 = "57f03a6c29793e8add7bd64186fc8066d23b5ffd06fe9cc6b0b8c499914d3a65",
+    urls = [
+        "https://mirror.bazel.build/github.com/uber/hermetic_cc_toolchain/releases/download/{0}/hermetic_cc_toolchain-{0}.tar.gz".format(HERMETIC_CC_TOOLCHAIN_VERSION),
+        "https://github.com/uber/hermetic_cc_toolchain/releases/download/{0}/hermetic_cc_toolchain-{0}.tar.gz".format(HERMETIC_CC_TOOLCHAIN_VERSION),
+    ],
 )

-load("@com_grail_bazel_toolchain//toolchain:deps.bzl", "bazel_toolchain_dependencies")
+load("@hermetic_cc_toolchain//toolchain:defs.bzl", zig_toolchains = "toolchains")

-bazel_toolchain_dependencies()
+zig_toolchains()

-load("@com_grail_bazel_toolchain//toolchain:rules.bzl", "llvm_toolchain")
-
-llvm_toolchain(
-    name = "llvm_toolchain",
-    llvm_version = "13.0.1",
+# Register zig sdk toolchains with support for Ubuntu 20.04 (Focal Fossa) which has an EOL date of April, 2025.
+# For ubuntu glibc support, see https://launchpad.net/ubuntu/+source/glibc
+register_toolchains(
+    "@zig_sdk//toolchain:linux_amd64_gnu.2.31",
+    "@zig_sdk//toolchain:linux_arm64_gnu.2.31",
+    # Hermetic cc toolchain is not yet supported on darwin. Sysroot needs to be provided.
+    # See https://github.com/uber/hermetic_cc_toolchain#osx-sysroot
+    #    "@zig_sdk//toolchain:darwin_amd64",
+    #    "@zig_sdk//toolchain:darwin_arm64",
+    # Windows builds are not supported yet.
+    #    "@zig_sdk//toolchain:windows_amd64",
 )

-load("@llvm_toolchain//:toolchains.bzl", "llvm_register_toolchains")
+load("@prysm//tools/cross-toolchain:darwin_cc_hack.bzl", "configure_nonhermetic_darwin")

-llvm_register_toolchains()
+configure_nonhermetic_darwin()

 load("@prysm//tools/cross-toolchain:prysm_toolchains.bzl", "configure_prysm_toolchains")

@@ -86,10 +96,10 @@ http_archive(
        # Expose internals of go_test for custom build transitions.
        "//third_party:io_bazel_rules_go_test.patch",
    ],
-    sha256 = "dd926a88a564a9246713a9c00b35315f54cbd46b31a26d5d8fb264c07045f05d",
+    sha256 = "6b65cb7917b4d1709f9410ffe00ecf3e160edf674b78c54a894471320862184f",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.38.1/rules_go-v0.38.1.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.38.1/rules_go-v0.38.1.zip",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.39.0/rules_go-v0.39.0.zip",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.39.0/rules_go-v0.39.0.zip",
    ],
 )

@@ -164,7 +174,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()

 go_register_toolchains(
-    go_version = "1.19.7",
+    go_version = "1.20.3",
    nogo = "@//:nogo",
 )

@@ -205,7 +215,7 @@ filegroup(
    url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )

-consensus_spec_version = "v1.3.0-rc.5"
+consensus_spec_version = "v1.4.0-alpha.1"

 bls_test_version = "v0.1.1"

@@ -221,7 +231,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "266006512e71e62396e8f31be01639560c9d59a93c38220fd8f51fabefc8f5f3",
+    sha256 = "1118a663be4a00ba00f0635eb20287157f2b2f993aed64335bfbcd04af424c2b",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )

@@ -237,7 +247,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "2ebf483830165909cb7961562fd369dedf079997a4832cc215a543898a73aa46",
+    sha256 = "acde6e10940d14f22277eda5b55b65a24623ac88e4c7a2e34134a6069f5eea82",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )

@@ -253,7 +263,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "333718ba5c907e0a99580caa8d28dd710543b3b271e4251581006d0e101fbce9",
+    sha256 = "49c022f3a3478cea849ba8f877a9f7e4c1ded549edddc09993550bbc5bb192e1",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )

@@ -268,7 +278,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "78b6925b5a4208e32385fa4387d2c27b381a8ddd18d66d5a7787e7846b86bfc8",
+    sha256 = "c3e246ff01f6b7b9e9e41939954a6ff89dfca7297415f88781809165fa83267c",
    strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
    url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )
@@ -311,11 +321,13 @@ http_archive(
    url = "https://github.com/bazelbuild/buildtools/archive/f2aed9ee205d62d45c55cfabbfd26342f8526862.zip",
 )

-git_repository(
+http_archive(
    name = "com_google_protobuf",
-    commit = "436bd7880e458532901c58f4d9d1ea23fa7edd52",
-    remote = "https://github.com/protocolbuffers/protobuf",
-    shallow_since = "1617835118 -0700",
+    sha256 = "4e176116949be52b0408dfd24f8925d1eb674a781ae242a75296b17a1c721395",
+    strip_prefix = "protobuf-23.3",
+    urls = [
+        "https://github.com/protocolbuffers/protobuf/archive/v23.3.tar.gz",
+    ],
 )

 # Group the sources of the library so that CMake rule have access to it
--- a/api/client/BUILD.bazel
+++ b/api/client/BUILD.bazel
@@ -0,0 +1,20 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "client.go",
+        "errors.go",
+        "options.go",
+    ],
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/client",
+    visibility = ["//visibility:public"],
+    deps = ["@com_github_pkg_errors//:go_default_library"],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["client_test.go"],
+    embed = [":go_default_library"],
+    deps = ["//testing/require:go_default_library"],
+)
--- a/api/client/beacon/BUILD.bazel
+++ b/api/client/beacon/BUILD.bazel
@@ -6,11 +6,11 @@ go_library(
        "checkpoint.go",
        "client.go",
        "doc.go",
-        "errors.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/v4/api/client/beacon",
    visibility = ["//visibility:public"],
    deps = [
+        "//api/client:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
        "//beacon-chain/rpc/apimiddleware:go_default_library",
        "//beacon-chain/state:go_default_library",
@@ -39,6 +39,7 @@ go_test(
    ],
    embed = [":go_default_library"],
    deps = [
+        "//api/client:go_default_library",
        "//beacon-chain/state:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/blocks:go_default_library",
--- a/api/client/beacon/checkpoint.go
+++ b/api/client/beacon/checkpoint.go
@@ -6,10 +6,12 @@ import (
 	"path"

 	"github.com/pkg/errors"
+	base "github.com/prysmaticlabs/prysm/v4/api/client"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v4/encoding/ssz/detect"
 	"github.com/prysmaticlabs/prysm/v4/io/file"
 	"github.com/prysmaticlabs/prysm/v4/runtime/version"
@@ -18,6 +20,8 @@ import (
 	"golang.org/x/mod/semver"
 )

+var errCheckpointBlockMismatch = errors.New("mismatch between checkpoint sync state and block")
+
 // OriginData represents the BeaconState and ReadOnlySignedBeaconBlock necessary to start an empty Beacon Node
 // using Checkpoint Sync.
 type OriginData struct {
@@ -74,37 +78,40 @@ func DownloadFinalizedData(ctx context.Context, client *Client) (*OriginData, er
 	if err != nil {
 		return nil, errors.Wrap(err, "error unmarshaling finalized state to correct version")
 	}
-	if s.Slot() != s.LatestBlockHeader().Slot {
-		return nil, fmt.Errorf("finalized state slot does not match latest block header slot %d != %d", s.Slot(), s.LatestBlockHeader().Slot)
-	}

-	sr, err := s.HashTreeRoot(ctx)
+	slot := s.LatestBlockHeader().Slot
+	bb, err := client.GetBlock(ctx, IdFromSlot(slot))
 	if err != nil {
-		return nil, errors.Wrapf(err, "failed to compute htr for finalized state at slot=%d", s.Slot())
-	}
-	header := s.LatestBlockHeader()
-	header.StateRoot = sr[:]
-	br, err := header.HashTreeRoot()
-	if err != nil {
-		return nil, errors.Wrap(err, "error while computing block root using state data")
-	}
-
-	bb, err := client.GetBlock(ctx, IdFromRoot(br))
-	if err != nil {
-		return nil, errors.Wrapf(err, "error requesting block by root = %#x", br)
+		return nil, errors.Wrapf(err, "error requesting block by slot = %d", slot)
 	}
 	b, err := vu.UnmarshalBeaconBlock(bb)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to unmarshal block to a supported type using the detected fork schedule")
 	}
-	realBlockRoot, err := b.Block().HashTreeRoot()
+	br, err := b.Block().HashTreeRoot()
 	if err != nil {
 		return nil, errors.Wrap(err, "error computing hash_tree_root of retrieved block")
 	}
+	bodyRoot, err := b.Block().Body().HashTreeRoot()
+	if err != nil {
+		return nil, errors.Wrap(err, "error computing hash_tree_root of retrieved block body")
+	}

-	log.Printf("BeaconState slot=%d, Block slot=%d", s.Slot(), b.Block().Slot())
-	log.Printf("BeaconState htr=%#x, Block state_root=%#x", sr, b.Block().StateRoot())
-	log.Printf("BeaconState latest_block_header htr=%#x, block htr=%#x", br, realBlockRoot)
+	sbr := bytesutil.ToBytes32(s.LatestBlockHeader().BodyRoot)
+	if sbr != bodyRoot {
+		return nil, errors.Wrapf(errCheckpointBlockMismatch, "state body root = %#x, block body root = %#x", sbr, bodyRoot)
+	}
+	sr, err := s.HashTreeRoot(ctx)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to compute htr for finalized state at slot=%d", s.Slot())
+	}
+
+	log.
+		WithField("block_slot", b.Block().Slot()).
+		WithField("state_slot", s.Slot()).
+		WithField("state_root", sr).
+		WithField("block_root", br).
+		Info("Downloaded checkpoint sync state and block.")
 	return &OriginData{
 		st: s,
 		b:  b,
@@ -126,7 +133,7 @@ type WeakSubjectivityData struct {
 }

 // CheckpointString returns the standard string representation of a Checkpoint.
-// The format is a a hex-encoded block root, followed by the epoch of the block, separated by a colon. For example:
+// The format is a hex-encoded block root, followed by the epoch of the block, separated by a colon. For example:
 // "0x1c35540cac127315fabb6bf29181f2ae0de1a3fc909d2e76ba771e61312cc49a:74888"
 func (wsd *WeakSubjectivityData) CheckpointString() string {
 	return fmt.Sprintf("%#x:%d", wsd.BlockRoot, wsd.Epoch)
@@ -140,7 +147,7 @@ func ComputeWeakSubjectivityCheckpoint(ctx context.Context, client *Client) (*We
 	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) {
+		if !errors.Is(err, base.ErrNotOK) {
 			return nil, errors.Wrap(err, "unexpected API response for prysm-only weak subjectivity checkpoint API")
 		}
 		// fall back to vanilla Beacon Node API method
--- a/api/client/beacon/checkpoint_test.go
+++ b/api/client/beacon/checkpoint_test.go
@@ -7,9 +7,9 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
 	"testing"

+	"github.com/prysmaticlabs/prysm/v4/api/client"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	blocktest "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks/testing"
@@ -66,11 +66,7 @@ func TestMarshalToEnvelope(t *testing.T) {
 }

 func TestFallbackVersionCheck(t *testing.T) {
-	c := &Client{
-		hc:      &http.Client{},
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
-	c.hc.Transport = &testRT{rt: func(req *http.Request) (*http.Response, error) {
+	trans := &testRT{rt: func(req *http.Request) (*http.Response, error) {
 		res := &http.Response{Request: req}
 		switch req.URL.Path {
 		case getNodeVersionPath:
@@ -88,12 +84,13 @@ func TestFallbackVersionCheck(t *testing.T) {
 		case getWeakSubjectivityPath:
 			res.StatusCode = http.StatusNotFound
 		}
-
 		return res, nil
 	}}

+	c, err := NewClient("http://localhost:3500", client.WithRoundTripper(trans))
+	require.NoError(t, err)
 	ctx := context.Background()
-	_, err := ComputeWeakSubjectivityCheckpoint(ctx, c)
+	_, err = ComputeWeakSubjectivityCheckpoint(ctx, c)
 	require.ErrorIs(t, err, errUnsupportedPrysmCheckpointVersion)
 }

@@ -131,6 +128,7 @@ func TestDownloadWeakSubjectivityCheckpoint(t *testing.T) {
 	wst, err := util.NewBeaconState()
 	require.NoError(t, err)
 	fork, err := forkForEpoch(cfg, epoch)
+	require.NoError(t, err)
 	require.NoError(t, wst.SetFork(fork))

 	// set up checkpoint block
@@ -170,44 +168,41 @@ func TestDownloadWeakSubjectivityCheckpoint(t *testing.T) {
 		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))
+	trans := &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,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
+		return res, nil
+	}}
+
+	c, err := NewClient("http://localhost:3500", client.WithRoundTripper(trans))
+	require.NoError(t, err)

 	wsd, err := ComputeWeakSubjectivityCheckpoint(ctx, c)
 	require.NoError(t, err)
@@ -232,6 +227,7 @@ func TestDownloadBackwardsCompatibleCombined(t *testing.T) {
 	wst, err := util.NewBeaconState()
 	require.NoError(t, err)
 	fork, err := forkForEpoch(cfg, cfg.GenesisEpoch)
+	require.NoError(t, err)
 	require.NoError(t, wst.SetFork(fork))

 	// set up checkpoint block
@@ -266,42 +262,39 @@ func TestDownloadBackwardsCompatibleCombined(t *testing.T) {
 	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))
+	trans := &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,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
+		return res, nil
+	}}
+
+	c, err := NewClient("http://localhost:3500", client.WithRoundTripper(trans))
+	require.NoError(t, err)

 	wsPub, err := ComputeWeakSubjectivityCheckpoint(ctx, c)
 	require.NoError(t, err)
@@ -315,21 +308,16 @@ 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,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
+	trans := &testRT{rt: func(req *http.Request) (*http.Response, error) {
+		res := &http.Response{Request: req}
+		if req.URL.Path == renderGetStatePath(IdHead) {
+			res.StatusCode = http.StatusOK
+			res.Body = io.NopCloser(bytes.NewBuffer(serialized))
+		}
+		return res, nil
+	}}
+	c, err := NewClient("http://localhost:3500", client.WithRoundTripper(trans))
+	require.NoError(t, err)
 	actualEpoch, err := getWeakSubjectivityEpochFromHead(context.Background(), c)
 	require.NoError(t, err)
 	require.Equal(t, expectedEpoch, actualEpoch)
@@ -413,6 +401,7 @@ func TestDownloadFinalizedData(t *testing.T) {
 	st, err := util.NewBeaconState()
 	require.NoError(t, err)
 	fork, err := forkForEpoch(cfg, epoch)
+	require.NoError(t, err)
 	require.NoError(t, st.SetFork(fork))
 	require.NoError(t, st.SetSlot(slot))

@@ -448,29 +437,24 @@ func TestDownloadFinalizedData(t *testing.T) {
 	ms, 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(IdFinalized):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(ms))
-			case renderGetBlockPath(IdFromRoot(br)):
-				res.StatusCode = http.StatusOK
-				res.Body = io.NopCloser(bytes.NewBuffer(mb))
-			default:
-				res.StatusCode = http.StatusInternalServerError
-				res.Body = io.NopCloser(bytes.NewBufferString(""))
-			}
-
-			return res, nil
-		}},
-	}
-	c := &Client{
-		hc:      hc,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
+	trans := &testRT{rt: func(req *http.Request) (*http.Response, error) {
+		res := &http.Response{Request: req}
+		switch req.URL.Path {
+		case renderGetStatePath(IdFinalized):
+			res.StatusCode = http.StatusOK
+			res.Body = io.NopCloser(bytes.NewBuffer(ms))
+		case renderGetBlockPath(IdFromSlot(b.Block().Slot())):
+			res.StatusCode = http.StatusOK
+			res.Body = io.NopCloser(bytes.NewBuffer(mb))
+		default:
+			res.StatusCode = http.StatusInternalServerError
+			res.Body = io.NopCloser(bytes.NewBufferString(""))
+		}

+		return res, nil
+	}}
+	c, err := NewClient("http://localhost:3500", client.WithRoundTripper(trans))
+	require.NoError(t, err)
 	// sanity check before we go through checkpoint
 	// make sure we can download the state and unmarshal it with the VersionedUnmarshaler
 	sb, err := c.GetState(ctx, IdFinalized)
--- a/api/client/beacon/client.go
+++ b/api/client/beacon/client.go
@@ -5,8 +5,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io"
-	"net"
 	"net/http"
 	"net/url"
 	"path"
@@ -14,8 +12,8 @@ import (
 	"sort"
 	"strconv"
 	"text/template"
-	"time"

+	"github.com/prysmaticlabs/prysm/v4/api/client"
 	"github.com/prysmaticlabs/prysm/v4/network/forks"
 	v1 "github.com/prysmaticlabs/prysm/v4/proto/eth/v1"

@@ -54,8 +52,6 @@ const (
 	IdFinalized StateOrBlockId = "finalized"
 )

-var ErrMalformedHostname = errors.New("hostname must include port, separated by one colon, like example.com:3500")
-
 // 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 {
@@ -85,96 +81,22 @@ func idTemplate(ts string) func(StateOrBlockId) string {
 	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
-	}
+func renderGetBlockPath(id StateOrBlockId) string {
+	return path.Join(getSignedBlockPath, string(id))
 }

 // Client provides a collection of helper methods for calling the Eth Beacon Node API endpoints.
 type Client struct {
-	hc      *http.Client
-	baseURL *url.URL
+	*client.Client
 }

-// 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) {
-	u, err := urlForHost(host)
+// NewClient returns a new Client that includes functions for rest calls to Beacon API.
+func NewClient(host string, opts ...client.ClientOpt) (*Client, error) {
+	c, err := client.NewClient(host, opts...)
 	if err != nil {
 		return nil, err
 	}
-	c := &Client{
-		hc:      &http.Client{},
-		baseURL: u,
-	}
-	for _, o := range opts {
-		o(c)
-	}
-	return c, nil
-}
-
-func urlForHost(h string) (*url.URL, error) {
-	// try to parse as url (being permissive)
-	u, err := url.Parse(h)
-	if err == nil && u.Host != "" {
-		return u, nil
-	}
-	// try to parse as host:port
-	host, port, err := net.SplitHostPort(h)
-	if err != nil {
-		return nil, ErrMalformedHostname
-	}
-	return &url.URL{Host: fmt.Sprintf("%s:%s", host, port), Scheme: "http"}, nil
-}
-
-// NodeURL returns a human-readable string representation of the beacon node base url.
-func (c *Client) NodeURL() string {
-	return c.baseURL.String()
-}
-
-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.baseURL.ResolveReference(&url.URL{Path: path})
-	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))
+	return &Client{c}, nil
 }

 // GetBlock retrieves the SignedBeaconBlock for the given block id.
@@ -184,7 +106,7 @@ func renderGetBlockPath(id StateOrBlockId) string {
 // 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())
+	b, err := c.Get(ctx, blockPath, client.WithSSZEncoding())
 	if err != nil {
 		return nil, errors.Wrapf(err, "error requesting state by id = %s", blockId)
 	}
@@ -199,7 +121,7 @@ var getBlockRootTpl = idTemplate(getBlockRootPath)
 // 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)
+	b, err := c.Get(ctx, rootPath)
 	if err != nil {
 		return [32]byte{}, errors.Wrapf(err, "error requesting block root by id = %s", blockId)
 	}
@@ -222,7 +144,7 @@ var getForkTpl = idTemplate(getForkForStatePath)
 // <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))
+	body, err := c.Get(ctx, getForkTpl(stateId))
 	if err != nil {
 		return nil, errors.Wrapf(err, "error requesting fork by state id = %s", stateId)
 	}
@@ -238,7 +160,7 @@ func (c *Client) GetFork(ctx context.Context, stateId StateOrBlockId) (*ethpb.Fo

 // 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)
+	body, err := c.Get(ctx, getForkSchedulePath)
 	if err != nil {
 		return nil, errors.Wrap(err, "error requesting fork schedule")
 	}
@@ -256,7 +178,7 @@ func (c *Client) GetForkSchedule(ctx context.Context) (forks.OrderedSchedule, er

 // GetConfigSpec retrieve the current configs of the network used by the beacon node.
 func (c *Client) GetConfigSpec(ctx context.Context) (*v1.SpecResponse, error) {
-	body, err := c.get(ctx, getConfigSpecPath)
+	body, err := c.Get(ctx, getConfigSpecPath)
 	if err != nil {
 		return nil, errors.Wrap(err, "error requesting configSpecPath")
 	}
@@ -279,7 +201,7 @@ var versionRE = regexp.MustCompile(`^(\w+)/(v\d+\.\d+\.\d+[-a-zA-Z0-9]*)\s*/?(.*
 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 nil, errors.Wrapf(client.ErrInvalidNodeVersion, "could not be parsed: %s", v)
 	}
 	return &NodeVersion{
 		implementation: groups[1],
@@ -291,7 +213,7 @@ func parseNodeVersion(v string) (*NodeVersion, error) {
 // 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)
+	b, err := c.Get(ctx, getNodeVersionPath)
 	if err != nil {
 		return nil, errors.Wrap(err, "error requesting node version")
 	}
@@ -318,7 +240,7 @@ func renderGetStatePath(id StateOrBlockId) string {
 // 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())
+	b, err := c.Get(ctx, statePath, client.WithSSZEncoding())
 	if err != nil {
 		return nil, errors.Wrapf(err, "error requesting state by id = %s", stateId)
 	}
@@ -331,7 +253,7 @@ func (c *Client) GetState(ctx context.Context, stateId StateOrBlockId) ([]byte,
 // - 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)
+	body, err := c.Get(ctx, getWeakSubjectivityPath)
 	if err != nil {
 		return nil, err
 	}
@@ -362,7 +284,7 @@ func (c *Client) GetWeakSubjectivity(ctx context.Context) (*WeakSubjectivityData
 // SubmitChangeBLStoExecution calls a beacon API endpoint to set the withdrawal addresses based on the given signed messages.
 // If the API responds with something other than OK there will be failure messages associated to the corresponding request message.
 func (c *Client) SubmitChangeBLStoExecution(ctx context.Context, request []*apimiddleware.SignedBLSToExecutionChangeJson) error {
-	u := c.baseURL.ResolveReference(&url.URL{Path: changeBLStoExecutionPath})
+	u := c.BaseURL().ResolveReference(&url.URL{Path: changeBLStoExecutionPath})
 	body, err := json.Marshal(request)
 	if err != nil {
 		return errors.Wrap(err, "failed to marshal JSON")
@@ -372,7 +294,7 @@ func (c *Client) SubmitChangeBLStoExecution(ctx context.Context, request []*apim
 		return errors.Wrap(err, "invalid format, failed to create new POST request object")
 	}
 	req.Header.Set("Content-Type", "application/json")
-	resp, err := c.hc.Do(req)
+	resp, err := c.Do(req)
 	if err != nil {
 		return err
 	}
@@ -401,7 +323,7 @@ func (c *Client) SubmitChangeBLStoExecution(ctx context.Context, request []*apim
 // GetBLStoExecutionChanges gets all the set withdrawal messages in the node's operation pool.
 // Returns a struct representation of json response.
 func (c *Client) GetBLStoExecutionChanges(ctx context.Context) (*apimiddleware.BLSToExecutionChangesPoolResponseJson, error) {
-	body, err := c.get(ctx, changeBLStoExecutionPath)
+	body, err := c.Get(ctx, changeBLStoExecutionPath)
 	if err != nil {
 		return nil, err
 	}
@@ -413,23 +335,6 @@ func (c *Client) GetBLStoExecutionChanges(ctx context.Context) (*apimiddleware.B
 	return poolResponse, nil
 }

-func non200Err(response *http.Response) error {
-	bodyBytes, err := io.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"`
--- a/api/client/beacon/client_test.go
+++ b/api/client/beacon/client_test.go
@@ -4,6 +4,7 @@ import (
 	"net/url"
 	"testing"

+	"github.com/prysmaticlabs/prysm/v4/api/client"
 	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

@@ -17,17 +18,17 @@ func TestParseNodeVersion(t *testing.T) {
 		{
 			name: "empty string",
 			v:    "",
-			err:  ErrInvalidNodeVersion,
+			err:  client.ErrInvalidNodeVersion,
 		},
 		{
 			name: "Prysm as the version string",
 			v:    "Prysm",
-			err:  ErrInvalidNodeVersion,
+			err:  client.ErrInvalidNodeVersion,
 		},
 		{
 			name: "semver only",
 			v:    "v2.0.6",
-			err:  ErrInvalidNodeVersion,
+			err:  client.ErrInvalidNodeVersion,
 		},
 		{
 			name: "complete version",
@@ -91,7 +92,7 @@ func TestValidHostname(t *testing.T) {
 		{
 			name:    "hostname without port",
 			hostArg: "mydomain.org",
-			err:     ErrMalformedHostname,
+			err:     client.ErrMalformedHostname,
 		},
 		{
 			name:    "hostname with port",
@@ -132,7 +133,7 @@ func TestValidHostname(t *testing.T) {
 				return
 			}
 			require.NoError(t, err)
-			require.Equal(t, c.joined, cl.baseURL.ResolveReference(&url.URL{Path: c.path}).String())
+			require.Equal(t, c.joined, cl.BaseURL().ResolveReference(&url.URL{Path: c.path}).String())
 		})
 	}
 }
--- 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/client/builder/BUILD.bazel
+++ b/api/client/builder/BUILD.bazel
@@ -11,10 +11,12 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/v4/api/client/builder",
    visibility = ["//visibility:public"],
    deps = [
+        "//consensus-types:go_default_library",
        "//consensus-types/blocks:go_default_library",
        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//encoding/bytesutil:go_default_library",
+        "//math:go_default_library",
        "//monitoring/tracing:go_default_library",
        "//network:go_default_library",
        "//network/authorization:go_default_library",
--- a/api/client/builder/bid.go
+++ b/api/client/builder/bid.go
@@ -4,9 +4,11 @@ import (
 	"math/big"

 	ssz "github.com/prysmaticlabs/fastssz"
+	consensus_types "github.com/prysmaticlabs/prysm/v4/consensus-types"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v4/math"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v4/runtime/version"
 )
@@ -38,7 +40,7 @@ type signedBuilderBid struct {
 func WrappedSignedBuilderBid(p *ethpb.SignedBuilderBid) (SignedBid, error) {
 	w := signedBuilderBid{p: p}
 	if w.IsNil() {
-		return nil, blocks.ErrNilObjectWrapped
+		return nil, consensus_types.ErrNilObjectWrapped
 	}
 	return w, nil
 }
@@ -71,7 +73,7 @@ type signedBuilderBidCapella struct {
 func WrappedSignedBuilderBidCapella(p *ethpb.SignedBuilderBidCapella) (SignedBid, error) {
 	w := signedBuilderBidCapella{p: p}
 	if w.IsNil() {
-		return nil, blocks.ErrNilObjectWrapped
+		return nil, consensus_types.ErrNilObjectWrapped
 	}
 	return w, nil
 }
@@ -104,7 +106,7 @@ type builderBid struct {
 func WrappedBuilderBid(p *ethpb.BuilderBid) (Bid, error) {
 	w := builderBid{p: p}
 	if w.IsNil() {
-		return nil, blocks.ErrNilObjectWrapped
+		return nil, consensus_types.ErrNilObjectWrapped
 	}
 	return w, nil
 }
@@ -152,7 +154,7 @@ type builderBidCapella struct {
 func WrappedBuilderBidCapella(p *ethpb.BuilderBidCapella) (Bid, error) {
 	w := builderBidCapella{p: p}
 	if w.IsNil() {
-		return nil, blocks.ErrNilObjectWrapped
+		return nil, consensus_types.ErrNilObjectWrapped
 	}
 	return w, nil
 }
@@ -160,8 +162,8 @@ func WrappedBuilderBidCapella(p *ethpb.BuilderBidCapella) (Bid, error) {
 // Header returns the execution data interface.
 func (b builderBidCapella) Header() (interfaces.ExecutionData, error) {
 	// We have to convert big endian to little endian because the value is coming from the execution layer.
-	v := bytesutil.ReverseByteOrder(b.p.Value)
-	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header, big.NewInt(0).SetBytes(v))
+	v := big.NewInt(0).SetBytes(bytesutil.ReverseByteOrder(b.p.Value))
+	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header, math.WeiToGwei(v))
 }

 // Version --
--- a/api/client/builder/client.go
+++ b/api/client/builder/client.go
@@ -6,13 +6,11 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"math/big"
 	"net"
 	"net/http"
 	"net/url"
 	"strings"
 	"text/template"
-	"time"

 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
@@ -37,7 +35,6 @@ const (
 var errMalformedHostname = errors.New("hostname must include port, separated by one colon, like example.com:3500")
 var errMalformedRequest = errors.New("required request data are missing")
 var errNotBlinded = errors.New("submitted block is not blinded")
-var submitBlindedBlockTimeout = 3 * time.Second

 // ClientOpt is a functional option for the Client type (http.Client wrapper)
 type ClientOpt func(*Client)
@@ -157,6 +154,7 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea
 	if err != nil {
 		return
 	}
+	req.Header.Add("User-Agent", version.BuildData())
 	for _, o := range opts {
 		o(req)
 	}
@@ -245,7 +243,6 @@ func (c *Client) GetHeader(ctx context.Context, slot primitives.Slot, parentHash
 	default:
 		return nil, fmt.Errorf("unsupported header version %s", strings.ToLower(v.Version))
 	}
-
 }

 // RegisterValidator encodes the SignedValidatorRegistrationV1 message to json (including hex-encoding the byte
@@ -293,8 +290,6 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 			return nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockBellatrix value body in SubmitBlindedBlock")
 		}

-		ctx, cancel := context.WithTimeout(ctx, submitBlindedBlockTimeout)
-		defer cancel()
 		versionOpt := func(r *http.Request) {
 			r.Header.Add("Eth-Consensus-Version", version.String(version.Bellatrix))
 		}
@@ -307,6 +302,9 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 		if err := json.Unmarshal(rb, ep); err != nil {
 			return nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlock response")
 		}
+		if strings.ToLower(ep.Version) != version.String(version.Bellatrix) {
+			return nil, errors.New("not a bellatrix payload")
+		}
 		p, err := ep.ToProto()
 		if err != nil {
 			return nil, errors.Wrapf(err, "could not extract proto message from payload")
@@ -323,8 +321,6 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 			return nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockCapella value body in SubmitBlindedBlockCapella")
 		}

-		ctx, cancel := context.WithTimeout(ctx, submitBlindedBlockTimeout)
-		defer cancel()
 		versionOpt := func(r *http.Request) {
 			r.Header.Add("Eth-Consensus-Version", version.String(version.Capella))
 		}
@@ -337,11 +333,14 @@ func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlyS
 		if err := json.Unmarshal(rb, ep); err != nil {
 			return nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlockCapella response")
 		}
+		if strings.ToLower(ep.Version) != version.String(version.Capella) {
+			return nil, errors.New("not a capella payload")
+		}
 		p, err := ep.ToProto()
 		if err != nil {
 			return nil, errors.Wrapf(err, "could not extract proto message from payload")
 		}
-		return blocks.WrappedExecutionPayloadCapella(p, big.NewInt(0))
+		return blocks.WrappedExecutionPayloadCapella(p, 0)
 	default:
 		return nil, fmt.Errorf("unsupported block version %s", version.String(sb.Version()))
 	}
--- a/api/client/builder/client_test.go
+++ b/api/client/builder/client_test.go
@@ -313,6 +313,26 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
 		assert.Equal(t, uint64(1), withdrawals[0].Amount)
 	})
+	t.Run("mismatched versions, expected bellatrix got capella", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayloadCapella)), // send a Capella payload
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
+		require.NoError(t, err)
+		_, err = c.SubmitBlindedBlock(ctx, sbbb)
+		require.ErrorContains(t, "not a bellatrix payload", err)
+	})
 	t.Run("not blinded", func(t *testing.T) {
 		sbb, err := blocks.NewSignedBeaconBlock(&eth.SignedBeaconBlockBellatrix{Block: &eth.BeaconBlockBellatrix{Body: &eth.BeaconBlockBodyBellatrix{}}})
 		require.NoError(t, err)
--- a/api/client/builder/types.go
+++ b/api/client/builder/types.go
@@ -14,14 +14,17 @@ import (
 	eth "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 )

+// SignedValidatorRegistration a struct for signed validator registrations.
 type SignedValidatorRegistration struct {
 	*eth.SignedValidatorRegistrationV1
 }

+// ValidatorRegistration a struct for validator registrations.
 type ValidatorRegistration struct {
 	*eth.ValidatorRegistrationV1
 }

+// MarshalJSON returns a json representation copy of signed validator registration.
 func (r *SignedValidatorRegistration) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Message   *ValidatorRegistration `json:"message"`
@@ -32,6 +35,7 @@ func (r *SignedValidatorRegistration) MarshalJSON() ([]byte, error) {
 	})
 }

+// UnmarshalJSON returns a byte representation of signed validator registration from json.
 func (r *SignedValidatorRegistration) UnmarshalJSON(b []byte) error {
 	if r.SignedValidatorRegistrationV1 == nil {
 		r.SignedValidatorRegistrationV1 = &eth.SignedValidatorRegistrationV1{}
@@ -48,6 +52,7 @@ func (r *SignedValidatorRegistration) UnmarshalJSON(b []byte) error {
 	return nil
 }

+// MarshalJSON returns a json representation copy of validator registration.
 func (r *ValidatorRegistration) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		FeeRecipient hexutil.Bytes `json:"fee_recipient"`
@@ -62,6 +67,7 @@ func (r *ValidatorRegistration) MarshalJSON() ([]byte, error) {
 	})
 }

+// UnmarshalJSON returns a byte representation of validator registration from json.
 func (r *ValidatorRegistration) UnmarshalJSON(b []byte) error {
 	if r.ValidatorRegistrationV1 == nil {
 		r.ValidatorRegistrationV1 = &eth.ValidatorRegistrationV1{}
@@ -92,6 +98,7 @@ func (r *ValidatorRegistration) UnmarshalJSON(b []byte) error {
 var errInvalidUint256 = errors.New("invalid Uint256")
 var errDecodeUint256 = errors.New("unable to decode into Uint256")

+// Uint256 a wrapper representation of big.Int
 type Uint256 struct {
 	*big.Int
 }
@@ -118,7 +125,7 @@ func sszBytesToUint256(b []byte) (Uint256, error) {
 	return Uint256{Int: bi}, nil
 }

-// SSZBytes creates an ssz-style (little-endian byte slice) representation of the Uint256
+// SSZBytes creates an ssz-style (little-endian byte slice) representation of the Uint256.
 func (s Uint256) SSZBytes() []byte {
 	if !isValidUint256(s.Int) {
 		return []byte{}
@@ -126,18 +133,19 @@ func (s Uint256) SSZBytes() []byte {
 	return bytesutil.PadTo(bytesutil.ReverseByteOrder(s.Int.Bytes()), 32)
 }

+// UnmarshalJSON takes in a byte array and unmarshals the value in Uint256
 func (s *Uint256) UnmarshalJSON(t []byte) error {
-	start := 0
 	end := len(t)
-	if t[0] == '"' {
-		start += 1
+	if len(t) < 2 {
+		return errors.Errorf("provided Uint256 json string is too short: %s", string(t))
 	}
-	if t[end-1] == '"' {
-		end -= 1
+	if t[0] != '"' || t[end-1] != '"' {
+		return errors.Errorf("provided Uint256 json string is malformed: %s", string(t))
 	}
-	return s.UnmarshalText(t[start:end])
+	return s.UnmarshalText(t[1 : end-1])
 }

+// UnmarshalText takes in a byte array and unmarshals the text in Uint256
 func (s *Uint256) UnmarshalText(t []byte) error {
 	if s.Int == nil {
 		s.Int = big.NewInt(0)
@@ -153,6 +161,7 @@ func (s *Uint256) UnmarshalText(t []byte) error {
 	return nil
 }

+// MarshalJSON returns a json byte representation of Uint256.
 func (s Uint256) MarshalJSON() ([]byte, error) {
 	t, err := s.MarshalText()
 	if err != nil {
@@ -163,6 +172,7 @@ func (s Uint256) MarshalJSON() ([]byte, error) {
 	return t, nil
 }

+// MarshalText returns a text byte representation of Uint256.
 func (s Uint256) MarshalText() ([]byte, error) {
 	if !isValidUint256(s.Int) {
 		return nil, errors.Wrapf(errInvalidUint256, "value=%s", s.Int)
@@ -170,22 +180,27 @@ func (s Uint256) MarshalText() ([]byte, error) {
 	return []byte(s.String()), nil
 }

+// Uint64String is a custom type that allows marshalling from text to uint64 and vice versa.
 type Uint64String uint64

+// UnmarshalText takes a byte array and unmarshals the text in Uint64String.
 func (s *Uint64String) UnmarshalText(t []byte) error {
 	u, err := strconv.ParseUint(string(t), 10, 64)
 	*s = Uint64String(u)
 	return err
 }

+// MarshalText returns a byte representation of the text from Uint64String.
 func (s Uint64String) MarshalText() ([]byte, error) {
 	return []byte(fmt.Sprintf("%d", s)), nil
 }

+// VersionResponse is a JSON representation of a field in the builder API header response.
 type VersionResponse struct {
 	Version string `json:"version"`
 }

+// ExecHeaderResponse is a JSON representation of  the builder API header response for Bellatrix.
 type ExecHeaderResponse struct {
 	Version string `json:"version"`
 	Data    struct {
@@ -194,6 +209,7 @@ type ExecHeaderResponse struct {
 	} `json:"data"`
 }

+// ToProto returns a SignedBuilderBid from ExecHeaderResponse for Bellatrix.
 func (ehr *ExecHeaderResponse) ToProto() (*eth.SignedBuilderBid, error) {
 	bb, err := ehr.Data.Message.ToProto()
 	if err != nil {
@@ -205,6 +221,7 @@ func (ehr *ExecHeaderResponse) ToProto() (*eth.SignedBuilderBid, error) {
 	}, nil
 }

+// ToProto returns a BuilderBid Proto for Bellatrix.
 func (bb *BuilderBid) ToProto() (*eth.BuilderBid, error) {
 	header, err := bb.Header.ToProto()
 	if err != nil {
@@ -217,31 +234,34 @@ func (bb *BuilderBid) ToProto() (*eth.BuilderBid, error) {
 	}, nil
 }

+// ToProto returns a ExecutionPayloadHeader for Bellatrix.
 func (h *ExecutionPayloadHeader) ToProto() (*v1.ExecutionPayloadHeader, error) {
 	return &v1.ExecutionPayloadHeader{
-		ParentHash:       h.ParentHash,
-		FeeRecipient:     h.FeeRecipient,
-		StateRoot:        h.StateRoot,
-		ReceiptsRoot:     h.ReceiptsRoot,
-		LogsBloom:        h.LogsBloom,
-		PrevRandao:       h.PrevRandao,
+		ParentHash:       bytesutil.SafeCopyBytes(h.ParentHash),
+		FeeRecipient:     bytesutil.SafeCopyBytes(h.FeeRecipient),
+		StateRoot:        bytesutil.SafeCopyBytes(h.StateRoot),
+		ReceiptsRoot:     bytesutil.SafeCopyBytes(h.ReceiptsRoot),
+		LogsBloom:        bytesutil.SafeCopyBytes(h.LogsBloom),
+		PrevRandao:       bytesutil.SafeCopyBytes(h.PrevRandao),
 		BlockNumber:      uint64(h.BlockNumber),
 		GasLimit:         uint64(h.GasLimit),
 		GasUsed:          uint64(h.GasUsed),
 		Timestamp:        uint64(h.Timestamp),
-		ExtraData:        h.ExtraData,
-		BaseFeePerGas:    h.BaseFeePerGas.SSZBytes(),
-		BlockHash:        h.BlockHash,
-		TransactionsRoot: h.TransactionsRoot,
+		ExtraData:        bytesutil.SafeCopyBytes(h.ExtraData),
+		BaseFeePerGas:    bytesutil.SafeCopyBytes(h.BaseFeePerGas.SSZBytes()),
+		BlockHash:        bytesutil.SafeCopyBytes(h.BlockHash),
+		TransactionsRoot: bytesutil.SafeCopyBytes(h.TransactionsRoot),
 	}, nil
 }

+// BuilderBid is part of ExecHeaderResponse for Bellatrix.
 type BuilderBid struct {
 	Header *ExecutionPayloadHeader `json:"header"`
 	Value  Uint256                 `json:"value"`
 	Pubkey hexutil.Bytes           `json:"pubkey"`
 }

+// ExecutionPayloadHeader is a field in BuilderBid.
 type ExecutionPayloadHeader struct {
 	ParentHash       hexutil.Bytes `json:"parent_hash"`
 	FeeRecipient     hexutil.Bytes `json:"fee_recipient"`
@@ -260,6 +280,7 @@ type ExecutionPayloadHeader struct {
 	*v1.ExecutionPayloadHeader
 }

+// MarshalJSON returns the JSON bytes representation of ExecutionPayloadHeader.
 func (h *ExecutionPayloadHeader) MarshalJSON() ([]byte, error) {
 	type MarshalCaller ExecutionPayloadHeader
 	baseFeePerGas, err := sszBytesToUint256(h.ExecutionPayloadHeader.BaseFeePerGas)
@@ -284,6 +305,7 @@ func (h *ExecutionPayloadHeader) MarshalJSON() ([]byte, error) {
 	})
 }

+// UnmarshalJSON takes in a JSON byte array and sets ExecutionPayloadHeader.
 func (h *ExecutionPayloadHeader) UnmarshalJSON(b []byte) error {
 	type UnmarshalCaller ExecutionPayloadHeader
 	uc := &UnmarshalCaller{}
@@ -297,11 +319,13 @@ func (h *ExecutionPayloadHeader) UnmarshalJSON(b []byte) error {
 	return err
 }

+// ExecPayloadResponse is the builder API /eth/v1/builder/blinded_blocks for Bellatrix.
 type ExecPayloadResponse struct {
 	Version string           `json:"version"`
 	Data    ExecutionPayload `json:"data"`
 }

+// ExecutionPayload is a field of ExecPayloadResponse
 type ExecutionPayload struct {
 	ParentHash    hexutil.Bytes   `json:"parent_hash"`
 	FeeRecipient  hexutil.Bytes   `json:"fee_recipient"`
@@ -319,33 +343,104 @@ type ExecutionPayload struct {
 	Transactions  []hexutil.Bytes `json:"transactions"`
 }

+// ToProto returns a ExecutionPayload Proto from ExecPayloadResponse
 func (r *ExecPayloadResponse) ToProto() (*v1.ExecutionPayload, error) {
 	return r.Data.ToProto()
 }

+// ToProto returns a ExecutionPayload Proto
 func (p *ExecutionPayload) ToProto() (*v1.ExecutionPayload, error) {
 	txs := make([][]byte, len(p.Transactions))
 	for i := range p.Transactions {
-		txs[i] = p.Transactions[i]
+		txs[i] = bytesutil.SafeCopyBytes(p.Transactions[i])
 	}
 	return &v1.ExecutionPayload{
-		ParentHash:    p.ParentHash,
-		FeeRecipient:  p.FeeRecipient,
-		StateRoot:     p.StateRoot,
-		ReceiptsRoot:  p.ReceiptsRoot,
-		LogsBloom:     p.LogsBloom,
-		PrevRandao:    p.PrevRandao,
+		ParentHash:    bytesutil.SafeCopyBytes(p.ParentHash),
+		FeeRecipient:  bytesutil.SafeCopyBytes(p.FeeRecipient),
+		StateRoot:     bytesutil.SafeCopyBytes(p.StateRoot),
+		ReceiptsRoot:  bytesutil.SafeCopyBytes(p.ReceiptsRoot),
+		LogsBloom:     bytesutil.SafeCopyBytes(p.LogsBloom),
+		PrevRandao:    bytesutil.SafeCopyBytes(p.PrevRandao),
 		BlockNumber:   uint64(p.BlockNumber),
 		GasLimit:      uint64(p.GasLimit),
 		GasUsed:       uint64(p.GasUsed),
 		Timestamp:     uint64(p.Timestamp),
-		ExtraData:     p.ExtraData,
-		BaseFeePerGas: p.BaseFeePerGas.SSZBytes(),
-		BlockHash:     p.BlockHash,
+		ExtraData:     bytesutil.SafeCopyBytes(p.ExtraData),
+		BaseFeePerGas: bytesutil.SafeCopyBytes(p.BaseFeePerGas.SSZBytes()),
+		BlockHash:     bytesutil.SafeCopyBytes(p.BlockHash),
 		Transactions:  txs,
 	}, nil
 }

+// FromProto converts a proto execution payload type to our builder
+// compatible payload type.
+func FromProto(payload *v1.ExecutionPayload) (ExecutionPayload, error) {
+	bFee, err := sszBytesToUint256(payload.BaseFeePerGas)
+	if err != nil {
+		return ExecutionPayload{}, err
+	}
+	txs := make([]hexutil.Bytes, len(payload.Transactions))
+	for i := range payload.Transactions {
+		txs[i] = bytesutil.SafeCopyBytes(payload.Transactions[i])
+	}
+	return ExecutionPayload{
+		ParentHash:    bytesutil.SafeCopyBytes(payload.ParentHash),
+		FeeRecipient:  bytesutil.SafeCopyBytes(payload.FeeRecipient),
+		StateRoot:     bytesutil.SafeCopyBytes(payload.StateRoot),
+		ReceiptsRoot:  bytesutil.SafeCopyBytes(payload.ReceiptsRoot),
+		LogsBloom:     bytesutil.SafeCopyBytes(payload.LogsBloom),
+		PrevRandao:    bytesutil.SafeCopyBytes(payload.PrevRandao),
+		BlockNumber:   Uint64String(payload.BlockNumber),
+		GasLimit:      Uint64String(payload.GasLimit),
+		GasUsed:       Uint64String(payload.GasUsed),
+		Timestamp:     Uint64String(payload.Timestamp),
+		ExtraData:     bytesutil.SafeCopyBytes(payload.ExtraData),
+		BaseFeePerGas: bFee,
+		BlockHash:     bytesutil.SafeCopyBytes(payload.BlockHash),
+		Transactions:  txs,
+	}, nil
+}
+
+// FromProtoCapella converts a proto execution payload type for capella to our
+// builder compatible payload type.
+func FromProtoCapella(payload *v1.ExecutionPayloadCapella) (ExecutionPayloadCapella, error) {
+	bFee, err := sszBytesToUint256(payload.BaseFeePerGas)
+	if err != nil {
+		return ExecutionPayloadCapella{}, err
+	}
+	txs := make([]hexutil.Bytes, len(payload.Transactions))
+	for i := range payload.Transactions {
+		txs[i] = bytesutil.SafeCopyBytes(payload.Transactions[i])
+	}
+	withdrawals := make([]Withdrawal, len(payload.Withdrawals))
+	for i, w := range payload.Withdrawals {
+		withdrawals[i] = Withdrawal{
+			Index:          Uint256{Int: big.NewInt(0).SetUint64(w.Index)},
+			ValidatorIndex: Uint256{Int: big.NewInt(0).SetUint64(uint64(w.ValidatorIndex))},
+			Address:        bytesutil.SafeCopyBytes(w.Address),
+			Amount:         Uint256{Int: big.NewInt(0).SetUint64(w.Amount)},
+		}
+	}
+	return ExecutionPayloadCapella{
+		ParentHash:    bytesutil.SafeCopyBytes(payload.ParentHash),
+		FeeRecipient:  bytesutil.SafeCopyBytes(payload.FeeRecipient),
+		StateRoot:     bytesutil.SafeCopyBytes(payload.StateRoot),
+		ReceiptsRoot:  bytesutil.SafeCopyBytes(payload.ReceiptsRoot),
+		LogsBloom:     bytesutil.SafeCopyBytes(payload.LogsBloom),
+		PrevRandao:    bytesutil.SafeCopyBytes(payload.PrevRandao),
+		BlockNumber:   Uint64String(payload.BlockNumber),
+		GasLimit:      Uint64String(payload.GasLimit),
+		GasUsed:       Uint64String(payload.GasUsed),
+		Timestamp:     Uint64String(payload.Timestamp),
+		ExtraData:     bytesutil.SafeCopyBytes(payload.ExtraData),
+		BaseFeePerGas: bFee,
+		BlockHash:     bytesutil.SafeCopyBytes(payload.BlockHash),
+		Transactions:  txs,
+		Withdrawals:   withdrawals,
+	}, nil
+}
+
+// ExecHeaderResponseCapella is the response of builder API /eth/v1/builder/header/{slot}/{parent_hash}/{pubkey} for Capella.
 type ExecHeaderResponseCapella struct {
 	Data struct {
 		Signature hexutil.Bytes      `json:"signature"`
@@ -353,6 +448,7 @@ type ExecHeaderResponseCapella struct {
 	} `json:"data"`
 }

+// ToProto returns a SignedBuilderBidCapella Proto from ExecHeaderResponseCapella.
 func (ehr *ExecHeaderResponseCapella) ToProto() (*eth.SignedBuilderBidCapella, error) {
 	bb, err := ehr.Data.Message.ToProto()
 	if err != nil {
@@ -360,10 +456,11 @@ func (ehr *ExecHeaderResponseCapella) ToProto() (*eth.SignedBuilderBidCapella, e
 	}
 	return &eth.SignedBuilderBidCapella{
 		Message:   bb,
-		Signature: ehr.Data.Signature,
+		Signature: bytesutil.SafeCopyBytes(ehr.Data.Signature),
 	}, nil
 }

+// ToProto returns a BuilderBidCapella Proto.
 func (bb *BuilderBidCapella) ToProto() (*eth.BuilderBidCapella, error) {
 	header, err := bb.Header.ToProto()
 	if err != nil {
@@ -371,37 +468,40 @@ func (bb *BuilderBidCapella) ToProto() (*eth.BuilderBidCapella, error) {
 	}
 	return &eth.BuilderBidCapella{
 		Header: header,
-		Value:  bb.Value.SSZBytes(),
-		Pubkey: bb.Pubkey,
+		Value:  bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
+		Pubkey: bytesutil.SafeCopyBytes(bb.Pubkey),
 	}, nil
 }

+// ToProto returns a ExecutionPayloadHeaderCapella Proto
 func (h *ExecutionPayloadHeaderCapella) ToProto() (*v1.ExecutionPayloadHeaderCapella, error) {
 	return &v1.ExecutionPayloadHeaderCapella{
-		ParentHash:       h.ParentHash,
-		FeeRecipient:     h.FeeRecipient,
-		StateRoot:        h.StateRoot,
-		ReceiptsRoot:     h.ReceiptsRoot,
-		LogsBloom:        h.LogsBloom,
-		PrevRandao:       h.PrevRandao,
+		ParentHash:       bytesutil.SafeCopyBytes(h.ParentHash),
+		FeeRecipient:     bytesutil.SafeCopyBytes(h.FeeRecipient),
+		StateRoot:        bytesutil.SafeCopyBytes(h.StateRoot),
+		ReceiptsRoot:     bytesutil.SafeCopyBytes(h.ReceiptsRoot),
+		LogsBloom:        bytesutil.SafeCopyBytes(h.LogsBloom),
+		PrevRandao:       bytesutil.SafeCopyBytes(h.PrevRandao),
 		BlockNumber:      uint64(h.BlockNumber),
 		GasLimit:         uint64(h.GasLimit),
 		GasUsed:          uint64(h.GasUsed),
 		Timestamp:        uint64(h.Timestamp),
-		ExtraData:        h.ExtraData,
-		BaseFeePerGas:    h.BaseFeePerGas.SSZBytes(),
-		BlockHash:        h.BlockHash,
-		TransactionsRoot: h.TransactionsRoot,
-		WithdrawalsRoot:  h.WithdrawalsRoot,
+		ExtraData:        bytesutil.SafeCopyBytes(h.ExtraData),
+		BaseFeePerGas:    bytesutil.SafeCopyBytes(h.BaseFeePerGas.SSZBytes()),
+		BlockHash:        bytesutil.SafeCopyBytes(h.BlockHash),
+		TransactionsRoot: bytesutil.SafeCopyBytes(h.TransactionsRoot),
+		WithdrawalsRoot:  bytesutil.SafeCopyBytes(h.WithdrawalsRoot),
 	}, nil
 }

+// BuilderBidCapella is field of ExecHeaderResponseCapella.
 type BuilderBidCapella struct {
 	Header *ExecutionPayloadHeaderCapella `json:"header"`
 	Value  Uint256                        `json:"value"`
 	Pubkey hexutil.Bytes                  `json:"pubkey"`
 }

+// ExecutionPayloadHeaderCapella is a field in BuilderBidCapella.
 type ExecutionPayloadHeaderCapella struct {
 	ParentHash       hexutil.Bytes `json:"parent_hash"`
 	FeeRecipient     hexutil.Bytes `json:"fee_recipient"`
@@ -421,6 +521,7 @@ type ExecutionPayloadHeaderCapella struct {
 	*v1.ExecutionPayloadHeaderCapella
 }

+// MarshalJSON returns a JSON byte representation of ExecutionPayloadHeaderCapella.
 func (h *ExecutionPayloadHeaderCapella) MarshalJSON() ([]byte, error) {
 	type MarshalCaller ExecutionPayloadHeaderCapella
 	baseFeePerGas, err := sszBytesToUint256(h.ExecutionPayloadHeaderCapella.BaseFeePerGas)
@@ -446,6 +547,7 @@ func (h *ExecutionPayloadHeaderCapella) MarshalJSON() ([]byte, error) {
 	})
 }

+// UnmarshalJSON takes a JSON byte array and sets ExecutionPayloadHeaderCapella.
 func (h *ExecutionPayloadHeaderCapella) UnmarshalJSON(b []byte) error {
 	type UnmarshalCaller ExecutionPayloadHeaderCapella
 	uc := &UnmarshalCaller{}
@@ -459,11 +561,13 @@ func (h *ExecutionPayloadHeaderCapella) UnmarshalJSON(b []byte) error {
 	return err
 }

+// ExecPayloadResponseCapella is the builder API /eth/v1/builder/blinded_blocks for Capella.
 type ExecPayloadResponseCapella struct {
 	Version string                  `json:"version"`
 	Data    ExecutionPayloadCapella `json:"data"`
 }

+// ExecutionPayloadCapella is a field of ExecPayloadResponseCapella.
 type ExecutionPayloadCapella struct {
 	ParentHash    hexutil.Bytes   `json:"parent_hash"`
 	FeeRecipient  hexutil.Bytes   `json:"fee_recipient"`
@@ -482,43 +586,46 @@ type ExecutionPayloadCapella struct {
 	Withdrawals   []Withdrawal    `json:"withdrawals"`
 }

+// ToProto returns a ExecutionPayloadCapella Proto.
 func (r *ExecPayloadResponseCapella) ToProto() (*v1.ExecutionPayloadCapella, error) {
 	return r.Data.ToProto()
 }

+// ToProto returns a ExecutionPayloadCapella Proto.
 func (p *ExecutionPayloadCapella) ToProto() (*v1.ExecutionPayloadCapella, error) {
 	txs := make([][]byte, len(p.Transactions))
 	for i := range p.Transactions {
-		txs[i] = p.Transactions[i]
+		txs[i] = bytesutil.SafeCopyBytes(p.Transactions[i])
 	}
 	withdrawals := make([]*v1.Withdrawal, len(p.Withdrawals))
 	for i, w := range p.Withdrawals {
 		withdrawals[i] = &v1.Withdrawal{
 			Index:          w.Index.Uint64(),
 			ValidatorIndex: types.ValidatorIndex(w.ValidatorIndex.Uint64()),
-			Address:        w.Address,
+			Address:        bytesutil.SafeCopyBytes(w.Address),
 			Amount:         w.Amount.Uint64(),
 		}
 	}
 	return &v1.ExecutionPayloadCapella{
-		ParentHash:    p.ParentHash,
-		FeeRecipient:  p.FeeRecipient,
-		StateRoot:     p.StateRoot,
-		ReceiptsRoot:  p.ReceiptsRoot,
-		LogsBloom:     p.LogsBloom,
-		PrevRandao:    p.PrevRandao,
+		ParentHash:    bytesutil.SafeCopyBytes(p.ParentHash),
+		FeeRecipient:  bytesutil.SafeCopyBytes(p.FeeRecipient),
+		StateRoot:     bytesutil.SafeCopyBytes(p.StateRoot),
+		ReceiptsRoot:  bytesutil.SafeCopyBytes(p.ReceiptsRoot),
+		LogsBloom:     bytesutil.SafeCopyBytes(p.LogsBloom),
+		PrevRandao:    bytesutil.SafeCopyBytes(p.PrevRandao),
 		BlockNumber:   uint64(p.BlockNumber),
 		GasLimit:      uint64(p.GasLimit),
 		GasUsed:       uint64(p.GasUsed),
 		Timestamp:     uint64(p.Timestamp),
-		ExtraData:     p.ExtraData,
-		BaseFeePerGas: p.BaseFeePerGas.SSZBytes(),
-		BlockHash:     p.BlockHash,
+		ExtraData:     bytesutil.SafeCopyBytes(p.ExtraData),
+		BaseFeePerGas: bytesutil.SafeCopyBytes(p.BaseFeePerGas.SSZBytes()),
+		BlockHash:     bytesutil.SafeCopyBytes(p.BlockHash),
 		Transactions:  txs,
 		Withdrawals:   withdrawals,
 	}, nil
 }

+// Withdrawal is a field of ExecutionPayloadCapella.
 type Withdrawal struct {
 	Index          Uint256       `json:"index"`
 	ValidatorIndex Uint256       `json:"validator_index"`
@@ -526,18 +633,22 @@ type Withdrawal struct {
 	Amount         Uint256       `json:"amount"`
 }

+// SignedBlindedBeaconBlockBellatrix is the request object for builder API /eth/v1/builder/blinded_blocks.
 type SignedBlindedBeaconBlockBellatrix struct {
 	*eth.SignedBlindedBeaconBlockBellatrix
 }

+// BlindedBeaconBlockBellatrix is a field in SignedBlindedBeaconBlockBellatrix.
 type BlindedBeaconBlockBellatrix struct {
 	*eth.BlindedBeaconBlockBellatrix
 }

+// BlindedBeaconBlockBodyBellatrix is a field in BlindedBeaconBlockBellatrix.
 type BlindedBeaconBlockBodyBellatrix struct {
 	*eth.BlindedBeaconBlockBodyBellatrix
 }

+// MarshalJSON returns a JSON byte array representation of SignedBlindedBeaconBlockBellatrix.
 func (r *SignedBlindedBeaconBlockBellatrix) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Message   *BlindedBeaconBlockBellatrix `json:"message"`
@@ -548,6 +659,7 @@ func (r *SignedBlindedBeaconBlockBellatrix) MarshalJSON() ([]byte, error) {
 	})
 }

+// MarshalJSON returns a JSON byte array representation of BlindedBeaconBlockBellatrix.
 func (b *BlindedBeaconBlockBellatrix) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Slot          string                           `json:"slot"`
@@ -564,10 +676,12 @@ func (b *BlindedBeaconBlockBellatrix) MarshalJSON() ([]byte, error) {
 	})
 }

+// ProposerSlashing is a field in BlindedBeaconBlockBodyCapella.
 type ProposerSlashing struct {
 	*eth.ProposerSlashing
 }

+// MarshalJSON returns a JSON byte array representation of ProposerSlashing.
 func (s *ProposerSlashing) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		SignedHeader1 *SignedBeaconBlockHeader `json:"signed_header_1"`
@@ -578,10 +692,12 @@ func (s *ProposerSlashing) MarshalJSON() ([]byte, error) {
 	})
 }

+// SignedBeaconBlockHeader is a field of ProposerSlashing.
 type SignedBeaconBlockHeader struct {
 	*eth.SignedBeaconBlockHeader
 }

+// MarshalJSON returns a JSON byte array representation of SignedBeaconBlockHeader.
 func (h *SignedBeaconBlockHeader) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Header    *BeaconBlockHeader `json:"message"`
@@ -592,10 +708,12 @@ func (h *SignedBeaconBlockHeader) MarshalJSON() ([]byte, error) {
 	})
 }

+// BeaconBlockHeader is a field of SignedBeaconBlockHeader.
 type BeaconBlockHeader struct {
 	*eth.BeaconBlockHeader
 }

+// MarshalJSON returns a JSON byte array representation of BeaconBlockHeader.
 func (h *BeaconBlockHeader) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Slot          string        `json:"slot"`
@@ -612,10 +730,12 @@ func (h *BeaconBlockHeader) MarshalJSON() ([]byte, error) {
 	})
 }

+// IndexedAttestation is a field of AttesterSlashing.
 type IndexedAttestation struct {
 	*eth.IndexedAttestation
 }

+// MarshalJSON returns a JSON byte array representation of IndexedAttestation.
 func (a *IndexedAttestation) MarshalJSON() ([]byte, error) {
 	indices := make([]string, len(a.IndexedAttestation.AttestingIndices))
 	for i := range a.IndexedAttestation.AttestingIndices {
@@ -632,10 +752,12 @@ func (a *IndexedAttestation) MarshalJSON() ([]byte, error) {
 	})
 }

+// AttesterSlashing is a field of a Beacon Block Body.
 type AttesterSlashing struct {
 	*eth.AttesterSlashing
 }

+// MarshalJSON returns a JSON byte array representation of AttesterSlashing.
 func (s *AttesterSlashing) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Attestation1 *IndexedAttestation `json:"attestation_1"`
@@ -646,10 +768,12 @@ func (s *AttesterSlashing) MarshalJSON() ([]byte, error) {
 	})
 }

+// Checkpoint is a field of AttestationData.
 type Checkpoint struct {
 	*eth.Checkpoint
 }

+// MarshalJSON returns a JSON byte array representation of Checkpoint.
 func (c *Checkpoint) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Epoch string        `json:"epoch"`
@@ -660,10 +784,12 @@ func (c *Checkpoint) MarshalJSON() ([]byte, error) {
 	})
 }

+// AttestationData is a field of IndexedAttestation.
 type AttestationData struct {
 	*eth.AttestationData
 }

+// MarshalJSON returns a JSON byte array representation of AttestationData.
 func (a *AttestationData) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Slot            string        `json:"slot"`
@@ -680,10 +806,12 @@ func (a *AttestationData) MarshalJSON() ([]byte, error) {
 	})
 }

+// Attestation is a field of Beacon Block Body.
 type Attestation struct {
 	*eth.Attestation
 }

+// MarshalJSON returns a JSON byte array representation of Attestation.
 func (a *Attestation) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		AggregationBits hexutil.Bytes    `json:"aggregation_bits"`
@@ -696,10 +824,12 @@ func (a *Attestation) MarshalJSON() ([]byte, error) {
 	})
 }

+// DepositData is a field of Deposit.
 type DepositData struct {
 	*eth.Deposit_Data
 }

+// MarshalJSON returns a JSON byte array representation of DepositData.
 func (d *DepositData) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		PublicKey             hexutil.Bytes `json:"pubkey"`
@@ -714,10 +844,12 @@ func (d *DepositData) MarshalJSON() ([]byte, error) {
 	})
 }

+// Deposit is a field of Beacon Block Body.
 type Deposit struct {
 	*eth.Deposit
 }

+// MarshalJSON returns a JSON byte array representation of Deposit.
 func (d *Deposit) MarshalJSON() ([]byte, error) {
 	proof := make([]hexutil.Bytes, len(d.Proof))
 	for i := range d.Proof {
@@ -732,10 +864,12 @@ func (d *Deposit) MarshalJSON() ([]byte, error) {
 	})
 }

+// SignedVoluntaryExit is a field of Beacon Block Body.
 type SignedVoluntaryExit struct {
 	*eth.SignedVoluntaryExit
 }

+// MarshalJSON returns a JSON byte array representation of SignedVoluntaryExit.
 func (sve *SignedVoluntaryExit) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Message   *VoluntaryExit `json:"message"`
@@ -746,10 +880,12 @@ func (sve *SignedVoluntaryExit) MarshalJSON() ([]byte, error) {
 	})
 }

+// VoluntaryExit is a field in SignedVoluntaryExit
 type VoluntaryExit struct {
 	*eth.VoluntaryExit
 }

+// MarshalJSON returns a JSON byte array representation of VoluntaryExit
 func (ve *VoluntaryExit) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Epoch          string `json:"epoch"`
@@ -760,10 +896,12 @@ func (ve *VoluntaryExit) MarshalJSON() ([]byte, error) {
 	})
 }

+// SyncAggregate is a field of Beacon Block Body.
 type SyncAggregate struct {
 	*eth.SyncAggregate
 }

+// MarshalJSON returns a JSON byte array representation of SyncAggregate.
 func (s *SyncAggregate) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		SyncCommitteeBits      hexutil.Bytes `json:"sync_committee_bits"`
@@ -774,10 +912,12 @@ func (s *SyncAggregate) MarshalJSON() ([]byte, error) {
 	})
 }

+// Eth1Data is a field of Beacon Block Body.
 type Eth1Data struct {
 	*eth.Eth1Data
 }

+// MarshalJSON returns a JSON byte array representation of Eth1Data.
 func (e *Eth1Data) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		DepositRoot  hexutil.Bytes `json:"deposit_root"`
@@ -790,6 +930,7 @@ func (e *Eth1Data) MarshalJSON() ([]byte, error) {
 	})
 }

+// MarshalJSON returns a JSON byte array representation of BlindedBeaconBlockBodyBellatrix.
 func (b *BlindedBeaconBlockBodyBellatrix) MarshalJSON() ([]byte, error) {
 	sve := make([]*SignedVoluntaryExit, len(b.BlindedBeaconBlockBodyBellatrix.VoluntaryExits))
 	for i := range b.BlindedBeaconBlockBodyBellatrix.VoluntaryExits {
@@ -836,10 +977,12 @@ func (b *BlindedBeaconBlockBodyBellatrix) MarshalJSON() ([]byte, error) {
 	})
 }

+// SignedBLSToExecutionChange is a field in Beacon Block Body for capella and above.
 type SignedBLSToExecutionChange struct {
 	*eth.SignedBLSToExecutionChange
 }

+// MarshalJSON returns a JSON byte array representation of SignedBLSToExecutionChange.
 func (ch *SignedBLSToExecutionChange) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Message   *BLSToExecutionChange `json:"message"`
@@ -850,10 +993,12 @@ func (ch *SignedBLSToExecutionChange) MarshalJSON() ([]byte, error) {
 	})
 }

+// BLSToExecutionChange is a field in SignedBLSToExecutionChange.
 type BLSToExecutionChange struct {
 	*eth.BLSToExecutionChange
 }

+// MarshalJSON returns a JSON byte array representation of BLSToExecutionChange.
 func (ch *BLSToExecutionChange) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		ValidatorIndex     string        `json:"validator_index"`
@@ -866,18 +1011,22 @@ func (ch *BLSToExecutionChange) MarshalJSON() ([]byte, error) {
 	})
 }

+// SignedBlindedBeaconBlockCapella is part of the request object sent to builder API /eth/v1/builder/blinded_blocks for Capella.
 type SignedBlindedBeaconBlockCapella struct {
 	*eth.SignedBlindedBeaconBlockCapella
 }

+// BlindedBeaconBlockCapella is a field in SignedBlindedBeaconBlockCapella.
 type BlindedBeaconBlockCapella struct {
 	*eth.BlindedBeaconBlockCapella
 }

+// BlindedBeaconBlockBodyCapella is a field in BlindedBeaconBlockCapella.
 type BlindedBeaconBlockBodyCapella struct {
 	*eth.BlindedBeaconBlockBodyCapella
 }

+// MarshalJSON returns a JSON byte array representation of SignedBlindedBeaconBlockCapella.
 func (b *SignedBlindedBeaconBlockCapella) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Message   *BlindedBeaconBlockCapella `json:"message"`
@@ -888,6 +1037,7 @@ func (b *SignedBlindedBeaconBlockCapella) MarshalJSON() ([]byte, error) {
 	})
 }

+// MarshalJSON returns a JSON byte array representation of BlindedBeaconBlockCapella
 func (b *BlindedBeaconBlockCapella) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Slot          string                         `json:"slot"`
@@ -904,6 +1054,7 @@ func (b *BlindedBeaconBlockCapella) MarshalJSON() ([]byte, error) {
 	})
 }

+// MarshalJSON returns a JSON byte array representation of BlindedBeaconBlockBodyCapella
 func (b *BlindedBeaconBlockBodyCapella) MarshalJSON() ([]byte, error) {
 	sve := make([]*SignedVoluntaryExit, len(b.VoluntaryExits))
 	for i := range b.VoluntaryExits {
@@ -956,6 +1107,7 @@ func (b *BlindedBeaconBlockBodyCapella) MarshalJSON() ([]byte, error) {
 	})
 }

+// ErrorMessage is a JSON representation of the builder API's returned error message.
 type ErrorMessage struct {
 	Code        int      `json:"code"`
 	Message     string   `json:"message"`
--- a/api/client/builder/types_test.go
+++ b/api/client/builder/types_test.go
@@ -1156,6 +1156,14 @@ func TestUint256Unmarshal(t *testing.T) {
 	require.Equal(t, expected, string(m))
 }

+func TestUint256Unmarshal_BadData(t *testing.T) {
+	var bigNum Uint256
+
+	assert.ErrorContains(t, "provided Uint256 json string is too short", bigNum.UnmarshalJSON([]byte{'"'}))
+	assert.ErrorContains(t, "provided Uint256 json string is malformed", bigNum.UnmarshalJSON([]byte{'"', '1', '2'}))
+
+}
+
 func TestUint256UnmarshalNegative(t *testing.T) {
 	m := "-1"
 	var value Uint256
--- a/api/client/client.go
+++ b/api/client/client.go
@@ -0,0 +1,97 @@
+package client
+
+import (
+	"context"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+
+	"github.com/pkg/errors"
+)
+
+// Client is a wrapper object around the HTTP client.
+type Client struct {
+	hc      *http.Client
+	baseURL *url.URL
+	token   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) {
+	u, err := urlForHost(host)
+	if err != nil {
+		return nil, err
+	}
+	c := &Client{
+		hc:      &http.Client{},
+		baseURL: u,
+	}
+	for _, o := range opts {
+		o(c)
+	}
+	return c, nil
+}
+
+// Token returns the bearer token used for jwt authentication
+func (c *Client) Token() string {
+	return c.token
+}
+
+// BaseURL returns the base url of the client
+func (c *Client) BaseURL() *url.URL {
+	return c.baseURL
+}
+
+// Do execute the request against the http client
+func (c *Client) Do(req *http.Request) (*http.Response, error) {
+	return c.hc.Do(req)
+}
+
+func urlForHost(h string) (*url.URL, error) {
+	// try to parse as url (being permissive)
+	u, err := url.Parse(h)
+	if err == nil && u.Host != "" {
+		return u, nil
+	}
+	// try to parse as host:port
+	host, port, err := net.SplitHostPort(h)
+	if err != nil {
+		return nil, ErrMalformedHostname
+	}
+	return &url.URL{Host: net.JoinHostPort(host, port), Scheme: "http"}, nil
+}
+
+// NodeURL returns a human-readable string representation of the beacon node base url.
+func (c *Client) NodeURL() string {
+	return c.baseURL.String()
+}
+
+// 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.baseURL.ResolveReference(&url.URL{Path: path})
+	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")
+	}
+	return b, nil
+}
--- a/api/client/client_test.go
+++ b/api/client/client_test.go
@@ -0,0 +1,48 @@
+package client
+
+import (
+	"net/url"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+)
+
+func TestValidHostname(t *testing.T) {
+	cases := []struct {
+		name    string
+		hostArg string
+		path    string
+		joined  string
+		err     error
+	}{
+		{
+			name:    "hostname without port",
+			hostArg: "mydomain.org",
+			err:     ErrMalformedHostname,
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			cl, err := NewClient(c.hostArg)
+			if c.err != nil {
+				require.ErrorIs(t, err, c.err)
+				return
+			}
+			require.NoError(t, err)
+			require.Equal(t, c.joined, cl.BaseURL().ResolveReference(&url.URL{Path: c.path}).String())
+		})
+	}
+}
+
+func TestWithAuthenticationToken(t *testing.T) {
+	cl, err := NewClient("https://www.offchainlabs.com:3500", WithAuthenticationToken("my token"))
+	require.NoError(t, err)
+	require.Equal(t, cl.Token(), "my token")
+}
+
+func TestBaseURL(t *testing.T) {
+	cl, err := NewClient("https://www.offchainlabs.com:3500")
+	require.NoError(t, err)
+	require.Equal(t, "www.offchainlabs.com", cl.BaseURL().Hostname())
+	require.Equal(t, "3500", cl.BaseURL().Port())
+}
--- a/api/client/errors.go
+++ b/api/client/errors.go
@@ -0,0 +1,40 @@
+package client
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/pkg/errors"
+)
+
+// ErrMalformedHostname is used to indicate if a host name's format is incorrect.
+var ErrMalformedHostname = errors.New("hostname must include port, separated by one colon, like example.com:3500")
+
+// ErrNotOK is used to indicate when an HTTP request to the 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")
+
+// Non200Err is a function that parses an HTTP response to handle responses that are not 200 with a formatted error.
+func Non200Err(response *http.Response) error {
+	bodyBytes, err := io.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)
+	}
+}
--- a/api/client/options.go
+++ b/api/client/options.go
@@ -0,0 +1,48 @@
+package client
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+)
+
+// ReqOption is a request functional option.
+type ReqOption func(*http.Request)
+
+// WithSSZEncoding is a request functional option that adds SSZ encoding header.
+func WithSSZEncoding() ReqOption {
+	return func(req *http.Request) {
+		req.Header.Set("Accept", "application/octet-stream")
+	}
+}
+
+// WithAuthorizationToken is a request functional option that adds header for authorization token.
+func WithAuthorizationToken(token string) ReqOption {
+	return func(req *http.Request) {
+		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
+	}
+}
+
+// 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
+	}
+}
+
+// WithRoundTripper replaces the underlying HTTP's transport with a custom one.
+func WithRoundTripper(t http.RoundTripper) ClientOpt {
+	return func(c *Client) {
+		c.hc.Transport = t
+	}
+}
+
+// WithAuthenticationToken sets an oauth token to be used.
+func WithAuthenticationToken(token string) ClientOpt {
+	return func(c *Client) {
+		c.token = token
+	}
+}
--- a/api/client/validator/BUILD.bazel
+++ b/api/client/validator/BUILD.bazel
@@ -0,0 +1,13 @@
+load("@prysm//tools/go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["client.go"],
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/client/validator",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//api/client:go_default_library",
+        "//validator/rpc/apimiddleware:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+    ],
+)
--- a/api/client/validator/client.go
+++ b/api/client/validator/client.go
@@ -0,0 +1,121 @@
+package validator
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v4/api/client"
+	"github.com/prysmaticlabs/prysm/v4/validator/rpc/apimiddleware"
+)
+
+const (
+	localKeysPath    = "/eth/v1/keystores"
+	remoteKeysPath   = "/eth/v1/remotekeys"
+	feeRecipientPath = "/eth/v1/validator/{pubkey}/feerecipient"
+)
+
+// Client provides a collection of helper methods for calling the Keymanager API endpoints.
+type Client struct {
+	*client.Client
+}
+
+// NewClient returns a new Client that includes functions for REST calls to keymanager APIs.
+func NewClient(host string, opts ...client.ClientOpt) (*Client, error) {
+	c, err := client.NewClient(host, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return &Client{c}, nil
+}
+
+// GetValidatorPubKeys gets the current list of web3signer or the local validator public keys in hex format.
+func (c *Client) GetValidatorPubKeys(ctx context.Context) ([]string, error) {
+	jsonlocal, err := c.GetLocalValidatorKeys(ctx)
+	if err != nil {
+		return nil, err
+	}
+	jsonremote, err := c.GetRemoteValidatorKeys(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if len(jsonlocal.Keystores) == 0 && len(jsonremote.Keystores) == 0 {
+		return nil, errors.New("there are no local keys or remote keys on the validator")
+	}
+
+	hexKeys := make(map[string]bool)
+
+	for index := range jsonlocal.Keystores {
+		hexKeys[jsonlocal.Keystores[index].ValidatingPubkey] = true
+	}
+	for index := range jsonremote.Keystores {
+		hexKeys[jsonremote.Keystores[index].Pubkey] = true
+	}
+	keys := make([]string, 0)
+	for k := range hexKeys {
+		keys = append(keys, k)
+	}
+	return keys, nil
+}
+
+// GetLocalValidatorKeys calls the keymanager APIs for local validator keys
+func (c *Client) GetLocalValidatorKeys(ctx context.Context) (*apimiddleware.ListKeystoresResponseJson, error) {
+	localBytes, err := c.Get(ctx, localKeysPath, client.WithAuthorizationToken(c.Token()))
+	if err != nil {
+		return nil, err
+	}
+	jsonlocal := &apimiddleware.ListKeystoresResponseJson{}
+	if err := json.Unmarshal(localBytes, jsonlocal); err != nil {
+		return nil, errors.Wrap(err, "failed to parse local keystore list")
+	}
+	return jsonlocal, nil
+}
+
+// GetRemoteValidatorKeys calls the keymanager APIs for web3signer validator keys
+func (c *Client) GetRemoteValidatorKeys(ctx context.Context) (*apimiddleware.ListRemoteKeysResponseJson, error) {
+	remoteBytes, err := c.Get(ctx, remoteKeysPath, client.WithAuthorizationToken(c.Token()))
+	if err != nil {
+		if !strings.Contains(err.Error(), "Prysm Wallet is not of type Web3Signer") {
+			return nil, err
+		}
+	}
+	jsonremote := &apimiddleware.ListRemoteKeysResponseJson{}
+	if len(remoteBytes) != 0 {
+		if err := json.Unmarshal(remoteBytes, jsonremote); err != nil {
+			return nil, errors.Wrap(err, "failed to parse remote keystore list")
+		}
+	}
+	return jsonremote, nil
+}
+
+// GetFeeRecipientAddresses takes a list of validators in hex format and returns an equal length list of fee recipients in hex format.
+func (c *Client) GetFeeRecipientAddresses(ctx context.Context, validators []string) ([]string, error) {
+	feeRecipients := make([]string, len(validators))
+	for index, validator := range validators {
+		feejson, err := c.GetFeeRecipientAddress(ctx, validator)
+		if err != nil {
+			return nil, errors.Wrap(err, fmt.Sprintf("keymanager API failed to retrieve fee recipient for validator %s", validators[index]))
+		}
+		if feejson.Data == nil {
+			continue
+		}
+		feeRecipients[index] = feejson.Data.Ethaddress
+	}
+	return feeRecipients, nil
+}
+
+// GetFeeRecipientAddress takes a public key and calls the keymanager API to return its fee recipient.
+func (c *Client) GetFeeRecipientAddress(ctx context.Context, pubkey string) (*apimiddleware.GetFeeRecipientByPubkeyResponseJson, error) {
+	path := strings.Replace(feeRecipientPath, "{pubkey}", pubkey, 1)
+	b, err := c.Get(ctx, path, client.WithAuthorizationToken(c.Token()))
+	if err != nil {
+		return nil, err
+	}
+	feejson := &apimiddleware.GetFeeRecipientByPubkeyResponseJson{}
+	if err := json.Unmarshal(b, feejson); err != nil {
+		return nil, errors.Wrap(err, "failed to parse fee recipient")
+	}
+	return feejson, nil
+}
--- a/async/event/feed.go
+++ b/async/event/feed.go
@@ -144,6 +144,7 @@ func (f *Feed) Send(value interface{}) (nsent int) {

 	if !f.typecheck(rvalue.Type()) {
 		f.sendLock <- struct{}{}
+		f.mu.Unlock()
 		panic(feedTypeError{op: "Send", got: rvalue.Type(), want: f.etype})
 	}
 	f.mu.Unlock()
--- a/async/event/feed_test.go
+++ b/async/event/feed_test.go
@@ -32,6 +32,8 @@ func TestFeedPanics(t *testing.T) {
 		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)) }))
+		// Validate it doesn't deadlock.
+		assert.NoError(t, checkPanic(want, func() { f.Send(uint64(2)) }))
 	}
 	{
 		var f Feed
--- a/async/scatter.go
+++ b/async/scatter.go
@@ -14,7 +14,7 @@ type WorkerResults struct {

 // Scatter scatters a computation across multiple goroutines.
 // This breaks the task in to a number of chunks and executes those chunks in parallel with the function provided.
-// Results returned are collected and presented a a set of WorkerResults, which can be reassembled by the calling function.
+// Results returned are collected and presented as a set of WorkerResults, which can be reassembled by the calling function.
 // Any error that occurs in the workers will be passed back to the calling function.
 func Scatter(inputLen int, sFunc func(int, int, *sync.RWMutex) (interface{}, error)) ([]*WorkerResults, error) {
 	if inputLen <= 0 {
--- a/beacon-chain/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -58,11 +58,13 @@ go_library(
        "//beacon-chain/operations/slashings:go_default_library",
        "//beacon-chain/operations/voluntaryexits:go_default_library",
        "//beacon-chain/p2p:go_default_library",
+        "//beacon-chain/startup:go_default_library",
        "//beacon-chain/state:go_default_library",
        "//beacon-chain/state/stategen:go_default_library",
        "//config/features:go_default_library",
        "//config/fieldparams:go_default_library",
        "//config/params:go_default_library",
+        "//consensus-types:go_default_library",
        "//consensus-types/blocks:go_default_library",
        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/payload-attribute:go_default_library",
@@ -118,6 +120,7 @@ go_test(
        "receive_attestation_test.go",
        "receive_block_test.go",
        "service_test.go",
+        "setup_test.go",
        "weak_subjectivity_checks_test.go",
    ],
    embed = [":go_default_library"],
@@ -167,6 +170,7 @@ go_test(
        "mock_test.go",
        "receive_block_test.go",
        "service_norace_test.go",
+        "setup_test.go",
    ],
    embed = [":go_default_library"],
    gc_goopts = [
--- a/beacon-chain/blockchain/chain_info.go
+++ b/beacon-chain/blockchain/chain_info.go
@@ -8,6 +8,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
@@ -85,6 +86,12 @@ type ForkFetcher interface {
 	TimeFetcher
 }

+// TemporalOracle is like ForkFetcher minus CurrentFork()
+type TemporalOracle interface {
+	GenesisFetcher
+	TimeFetcher
+}
+
 // CanonicalFetcher retrieves the current chain's canonical information.
 type CanonicalFetcher interface {
 	IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error)
@@ -96,7 +103,7 @@ type FinalizationFetcher interface {
 	FinalizedCheckpt() *ethpb.Checkpoint
 	CurrentJustifiedCheckpt() *ethpb.Checkpoint
 	PreviousJustifiedCheckpt() *ethpb.Checkpoint
-	UnrealizedJustifiedPayloadBlockHash() ([32]byte, error)
+	UnrealizedJustifiedPayloadBlockHash() [32]byte
 	FinalizedBlockHash() [32]byte
 	InForkchoice([32]byte) bool
 	IsFinalized(ctx context.Context, blockRoot [32]byte) bool
@@ -327,13 +334,19 @@ func (s *Service) HeadValidatorIndexToPublicKey(_ context.Context, index primiti
 }

 // IsOptimistic returns true if the current head is optimistic.
-func (s *Service) IsOptimistic(ctx context.Context) (bool, error) {
+func (s *Service) IsOptimistic(_ context.Context) (bool, error) {
 	if slots.ToEpoch(s.CurrentSlot()) < params.BeaconConfig().BellatrixForkEpoch {
 		return false, nil
 	}
 	s.headLock.RLock()
 	headRoot := s.head.root
+	headSlot := s.head.slot
+	headOptimistic := s.head.optimistic
 	s.headLock.RUnlock()
+	// we trust the head package for recent head slots, otherwise fallback to forkchoice
+	if headSlot+2 >= s.CurrentSlot() {
+		return headOptimistic, nil
+	}

 	s.cfg.ForkChoiceStore.RLock()
 	defer s.cfg.ForkChoiceStore.RUnlock()
@@ -374,6 +387,14 @@ func (s *Service) InForkchoice(root [32]byte) bool {
 	return s.cfg.ForkChoiceStore.HasNode(root)
 }

+// IsViableForkCheckpoint returns whether the given checkpoint is a checkpoint in any
+// chain known to forkchoice
+func (s *Service) IsViableForCheckpoint(cp *forkchoicetypes.Checkpoint) (bool, error) {
+	s.cfg.ForkChoiceStore.RLock()
+	defer s.cfg.ForkChoiceStore.RUnlock()
+	return s.cfg.ForkChoiceStore.IsViableForCheckpoint(cp)
+}
+
 // IsOptimisticForRoot takes the root as argument instead of the current head
 // and returns true if it is optimistic.
 func (s *Service) IsOptimisticForRoot(ctx context.Context, root [32]byte) (bool, error) {
--- a/beacon-chain/blockchain/chain_info_forkchoice.go
+++ b/beacon-chain/blockchain/chain_info_forkchoice.go
@@ -80,7 +80,7 @@ func (s *Service) ChainHeads() ([][32]byte, []primitives.Slot) {
 }

 // UnrealizedJustifiedPayloadBlockHash returns unrealized justified payload block hash from forkchoice.
-func (s *Service) UnrealizedJustifiedPayloadBlockHash() ([32]byte, error) {
+func (s *Service) UnrealizedJustifiedPayloadBlockHash() [32]byte {
 	s.cfg.ForkChoiceStore.RLock()
 	defer s.cfg.ForkChoiceStore.RUnlock()
 	return s.cfg.ForkChoiceStore.UnrealizedJustifiedPayloadBlockHash()
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -10,7 +10,6 @@ import (
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	state_native "github.com/prysmaticlabs/prysm/v4/beacon-chain/state/state-native"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
@@ -72,16 +71,8 @@ func TestHeadRoot_Nil(t *testing.T) {
 }

 func TestFinalizedCheckpt_GenesisRootOk(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(fcs),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, fcs := tr.ctx, tr.fcs

 	gs, _ := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -97,16 +88,8 @@ func TestFinalizedCheckpt_GenesisRootOk(t *testing.T) {
 }

 func TestCurrentJustifiedCheckpt_CanRetrieve(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(fcs),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs

 	jroot := [32]byte{'j'}
 	cp := &forkchoicetypes.Checkpoint{Epoch: 6, Root: jroot}
@@ -120,16 +103,8 @@ func TestCurrentJustifiedCheckpt_CanRetrieve(t *testing.T) {
 }

 func TestFinalizedBlockHash(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(fcs),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs

 	r := [32]byte{'f'}
 	cp := &forkchoicetypes.Checkpoint{Epoch: 6, Root: r}
@@ -153,8 +128,7 @@ func TestUnrealizedJustifiedBlockHash(t *testing.T) {
 	service.cfg.ForkChoiceStore.SetBalancesByRooter(func(_ context.Context, _ [32]byte) ([]uint64, error) { return []uint64{}, nil })
 	require.NoError(t, service.cfg.ForkChoiceStore.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{Epoch: 6, Root: [32]byte{'j'}}))

-	h, err := service.UnrealizedJustifiedPayloadBlockHash()
-	require.NoError(t, err)
+	h := service.UnrealizedJustifiedPayloadBlockHash()
 	require.Equal(t, params.BeaconConfig().ZeroHash, h)
 	require.Equal(t, [32]byte{'j'}, service.cfg.ForkChoiceStore.JustifiedCheckpoint().Root)
 }
@@ -171,16 +145,9 @@ func TestHeadSlot_CanRetrieve(t *testing.T) {
 }

 func TestHeadRoot_CanRetrieve(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(fcs),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+
 	gs, _ := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))

@@ -190,16 +157,8 @@ func TestHeadRoot_CanRetrieve(t *testing.T) {
 }

 func TestHeadRoot_UseDB(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(fcs),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

 	service.head = &head{root: params.BeaconConfig().ZeroHash}
 	b := util.NewBeaconBlock()
@@ -463,6 +422,12 @@ func TestService_IsOptimistic(t *testing.T) {

 	opt, err := c.IsOptimistic(ctx)
 	require.NoError(t, err)
+	require.Equal(t, primitives.Slot(0), c.CurrentSlot())
+	require.Equal(t, false, opt)
+
+	c.SetGenesisTime(time.Now().Add(-time.Second * time.Duration(4*params.BeaconConfig().SecondsPerSlot)))
+	opt, err = c.IsOptimistic(ctx)
+	require.NoError(t, err)
 	require.Equal(t, true, opt)
 }

--- a/beacon-chain/blockchain/error.go
+++ b/beacon-chain/blockchain/error.go
@@ -25,8 +25,11 @@ var (
 	errWSBlockNotFound = errors.New("weak subjectivity root not found in db")
 	// errWSBlockNotFoundInEpoch is returned when a block is not found in the WS cache or DB within epoch.
 	errWSBlockNotFoundInEpoch = errors.New("weak subjectivity root not found in db within epoch")
-	// errNotDescendantOfFinalized is returned when a block is not a descendant of the finalized checkpoint
+	// ErrNotDescendantOfFinalized is returned when a block is not a descendant of the finalized checkpoint
 	ErrNotDescendantOfFinalized = invalidBlock{error: errors.New("not descendant of finalized checkpoint")}
+	// ErrNotCheckpoint is returned when a given checkpoint is not a
+	// checkpoint in any chain known to forkchoice
+	ErrNotCheckpoint = errors.New("not a checkpoint in forkchoice")
 )

 // An invalid block is the block that fails state transition based on the core protocol rules.
@@ -38,13 +41,15 @@ var (
 type invalidBlock struct {
 	invalidAncestorRoots [][32]byte
 	error
-	root [32]byte
+	root          [32]byte
+	lastValidHash [32]byte
 }

 type invalidBlockError interface {
 	Error() string
 	InvalidAncestorRoots() [][32]byte
 	BlockRoot() [32]byte
+	LastValidHash() [32]byte
 }

 // BlockRoot returns the invalid block root.
@@ -52,6 +57,11 @@ func (e invalidBlock) BlockRoot() [32]byte {
 	return e.root
 }

+// LastValidHash returns the last valid hash root.
+func (e invalidBlock) LastValidHash() [32]byte {
+	return e.lastValidHash
+}
+
 // InvalidAncestorRoots returns an optional list of invalid roots of the invalid block which leads up last valid root.
 func (e invalidBlock) InvalidAncestorRoots() [][32]byte {
 	return e.invalidAncestorRoots
@@ -69,6 +79,19 @@ func IsInvalidBlock(e error) bool {
 	return true
 }

+// InvalidBlockLVH returns the invalid block last valid hash root. If the error
+// doesn't have a last valid hash, [32]byte{} is returned.
+func InvalidBlockLVH(e error) [32]byte {
+	if e == nil {
+		return [32]byte{}
+	}
+	d, ok := e.(invalidBlockError)
+	if !ok {
+		return [32]byte{}
+	}
+	return d.LastValidHash()
+}
+
 // InvalidBlockRoot returns the invalid block root. If the error
 // doesn't have an invalid blockroot. [32]byte{} is returned.
 func InvalidBlockRoot(e error) [32]byte {
--- a/beacon-chain/blockchain/execution_engine.go
+++ b/beacon-chain/blockchain/execution_engine.go
@@ -12,6 +12,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db/kv"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/execution"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
@@ -61,11 +62,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *notifyForkcho
 		return nil, nil
 	}
 	finalizedHash := s.cfg.ForkChoiceStore.FinalizedPayloadBlockHash()
-	justifiedHash, err := s.cfg.ForkChoiceStore.UnrealizedJustifiedPayloadBlockHash()
-	if err != nil {
-		log.WithError(err).Error("Could not get unrealized justified payload block hash")
-		justifiedHash = finalizedHash
-	}
+	justifiedHash := s.cfg.ForkChoiceStore.UnrealizedJustifiedPayloadBlockHash()
 	fcs := &enginev1.ForkchoiceState{
 		HeadBlockHash:      headPayload.BlockHash(),
 		SafeBlockHash:      justifiedHash[:],
@@ -73,8 +70,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *notifyForkcho
 	}

 	nextSlot := s.CurrentSlot() + 1 // Cache payload ID for next slot proposer.
-	hasAttr, attr, proposerId := s.getPayloadAttribute(ctx, arg.headState, nextSlot)
-
+	hasAttr, attr, proposerId := s.getPayloadAttribute(ctx, arg.headState, nextSlot, arg.headRoot[:])
 	payloadID, lastValidHash, err := s.cfg.ExecutionEngineCaller.ForkchoiceUpdated(ctx, fcs, attr)
 	if err != nil {
 		switch err {
@@ -157,7 +153,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *notifyForkcho
 		var pId [8]byte
 		copy(pId[:], payloadID[:])
 		s.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(nextSlot, proposerId, pId, arg.headRoot)
-	} else if hasAttr && payloadID == nil {
+	} else if hasAttr && payloadID == nil && !features.Get().PrepareAllPayloads {
 		log.WithFields(logrus.Fields{
 			"blockHash": fmt.Sprintf("%#x", headPayload.BlockHash()),
 			"slot":      headBlk.Slot(),
@@ -223,51 +219,56 @@ func (s *Service) notifyNewPayload(ctx context.Context, postStateVersion int,
 		}).Info("Called new payload with optimistic block")
 		return false, nil
 	case execution.ErrInvalidPayloadStatus:
-		newPayloadInvalidNodeCount.Inc()
-		root, err := blk.Block().HashTreeRoot()
-		if err != nil {
-			return false, err
-		}
-		invalidRoots, err := s.cfg.ForkChoiceStore.SetOptimisticToInvalid(ctx, root, blk.Block().ParentRoot(), bytesutil.ToBytes32(lastValidHash))
-		if err != nil {
-			return false, err
-		}
-		if err := s.removeInvalidBlockAndState(ctx, invalidRoots); err != nil {
-			return false, err
-		}
-		log.WithFields(logrus.Fields{
-			"slot":                 blk.Block().Slot(),
-			"blockRoot":            fmt.Sprintf("%#x", root),
-			"invalidChildrenCount": len(invalidRoots),
-		}).Warn("Pruned invalid blocks")
+		lvh := bytesutil.ToBytes32(lastValidHash)
 		return false, invalidBlock{
-			invalidAncestorRoots: invalidRoots,
-			error:                ErrInvalidPayload,
+			error:         ErrInvalidPayload,
+			lastValidHash: lvh,
 		}
-	case execution.ErrInvalidBlockHashPayloadStatus:
-		newPayloadInvalidNodeCount.Inc()
-		return false, ErrInvalidBlockHashPayloadStatus
 	default:
 		return false, errors.WithMessage(ErrUndefinedExecutionEngineError, err.Error())
 	}
 }

+// reportInvalidBlock deals with the event that an invalid block was detected by the execution layer
+func (s *Service) reportInvalidBlock(ctx context.Context, root, parentRoot, lvh [32]byte) error {
+	newPayloadInvalidNodeCount.Inc()
+	invalidRoots, err := s.cfg.ForkChoiceStore.SetOptimisticToInvalid(ctx, root, parentRoot, lvh)
+	if err != nil {
+		return err
+	}
+	if err := s.removeInvalidBlockAndState(ctx, invalidRoots); err != nil {
+		return err
+	}
+	log.WithFields(logrus.Fields{
+		"blockRoot":            fmt.Sprintf("%#x", root),
+		"invalidChildrenCount": len(invalidRoots),
+	}).Warn("Pruned invalid blocks")
+	return invalidBlock{
+		invalidAncestorRoots: invalidRoots,
+		error:                ErrInvalidPayload,
+		lastValidHash:        lvh,
+	}
+}
+
 // getPayloadAttributes returns the payload attributes for the given state and slot.
 // The attribute is required to initiate a payload build process in the context of an `engine_forkchoiceUpdated` call.
-func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState, slot primitives.Slot) (bool, payloadattribute.Attributer, primitives.ValidatorIndex) {
+func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState, slot primitives.Slot, headRoot []byte) (bool, payloadattribute.Attributer, primitives.ValidatorIndex) {
 	emptyAttri := payloadattribute.EmptyWithVersion(st.Version())
 	// Root is `[32]byte{}` since we are retrieving proposer ID of a given slot. During insertion at assignment the root was not known.
 	proposerID, _, ok := s.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(slot, [32]byte{} /* root */)
-	if !ok { // There's no need to build attribute if there is no proposer for slot.
+	if !ok && !features.Get().PrepareAllPayloads { // There's no need to build attribute if there is no proposer for slot.
 		return false, emptyAttri, 0
 	}

 	// Get previous randao.
 	st = st.Copy()
-	st, err := transition.ProcessSlotsIfPossible(ctx, st, slot)
-	if err != nil {
-		log.WithError(err).Error("Could not process slots to get payload attribute")
-		return false, emptyAttri, 0
+	if slot > st.Slot() {
+		var err error
+		st, err = transition.ProcessSlotsUsingNextSlotCache(ctx, st, headRoot, slot)
+		if err != nil {
+			log.WithError(err).Error("Could not process slots to get payload attribute")
+			return false, emptyAttri, 0
+		}
 	}
 	prevRando, err := helpers.RandaoMix(st, time.CurrentEpoch(st))
 	if err != nil {
--- a/beacon-chain/blockchain/execution_engine_test.go
+++ b/beacon-chain/blockchain/execution_engine_test.go
@@ -9,14 +9,12 @@ import (
 	gethtypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
-	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/execution"
 	mockExecution "github.com/prysmaticlabs/prysm/v4/beacon-chain/execution/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
 	bstate "github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	state_native "github.com/prysmaticlabs/prysm/v4/beacon-chain/state/state-native"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
 	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
@@ -32,23 +30,16 @@ import (
 )

 func Test_NotifyForkchoiceUpdate_GetPayloadAttrErrorCanContinue(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs
+
 	altairBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockAltair())
 	altairBlkRoot, err := altairBlk.Block().HashTreeRoot()
 	require.NoError(t, err)
 	bellatrixBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockBellatrix())
 	bellatrixBlkRoot, err := bellatrixBlk.Block().HashTreeRoot()
 	require.NoError(t, err)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+
 	st, _ := util.DeterministicGenesisState(t, 10)
 	service.head = &head{
 		state: st,
@@ -95,23 +86,15 @@ func Test_NotifyForkchoiceUpdate_GetPayloadAttrErrorCanContinue(t *testing.T) {
 }

 func Test_NotifyForkchoiceUpdate(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs
+
 	altairBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockAltair())
 	altairBlkRoot, err := altairBlk.Block().HashTreeRoot()
 	require.NoError(t, err)
 	bellatrixBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockBellatrix())
 	bellatrixBlkRoot, err := bellatrixBlk.Block().HashTreeRoot()
 	require.NoError(t, err)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	st, _ := util.DeterministicGenesisState(t, 10)
 	service.head = &head{
 		state: st,
@@ -263,8 +246,8 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 }

 func Test_NotifyForkchoiceUpdate_NIlLVH(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs

 	// Prepare blocks
 	ba := util.NewBeaconBlockBellatrix()
@@ -296,12 +279,6 @@ func Test_NotifyForkchoiceUpdate_NIlLVH(t *testing.T) {
 	brd, err := wbd.Block().HashTreeRoot()
 	require.NoError(t, err)

-	// Insert blocks into forkchoice
-	service := setupBeaconChain(t, beaconDB)
-	fcs := doublylinkedtree.New()
-	service.cfg.ForkChoiceStore = fcs
-	service.cfg.ProposerSlotIndexCache = cache.NewProposerPayloadIDsCache()
-
 	fcs.SetBalancesByRooter(func(context.Context, [32]byte) ([]uint64, error) { return []uint64{50, 100, 200}, nil })
 	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{}))
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
@@ -357,8 +334,8 @@ func Test_NotifyForkchoiceUpdate_NIlLVH(t *testing.T) {
 // 3. the blockchain package calls fcu to obtain heads G -> F -> D.

 func Test_NotifyForkchoiceUpdateRecursive_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs

 	// Prepare blocks
 	ba := util.NewBeaconBlockBellatrix()
@@ -413,12 +390,6 @@ func Test_NotifyForkchoiceUpdateRecursive_DoublyLinkedTree(t *testing.T) {
 	brg, err := wbg.Block().HashTreeRoot()
 	require.NoError(t, err)

-	// Insert blocks into forkchoice
-	service := setupBeaconChain(t, beaconDB)
-	fcs := doublylinkedtree.New()
-	service.cfg.ForkChoiceStore = fcs
-	service.cfg.ProposerSlotIndexCache = cache.NewProposerPayloadIDsCache()
-
 	fcs.SetBalancesByRooter(func(context.Context, [32]byte) ([]uint64, error) { return []uint64{50, 100, 200}, nil })
 	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{}))
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
@@ -496,15 +467,9 @@ func Test_NotifyNewPayload(t *testing.T) {
 	cfg := params.BeaconConfig()
 	cfg.TerminalTotalDifficulty = "2"
 	params.OverrideBeaconConfig(cfg)
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx, fcs := tr.ctx, tr.fcs

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
 	phase0State, _ := util.DeterministicGenesisState(t, 1)
 	altairState, _ := util.DeterministicGenesisStateAltair(t, 1)
 	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
@@ -535,8 +500,6 @@ func Test_NotifyNewPayload(t *testing.T) {
 	}
 	bellatrixBlk, err := consensusblocks.NewSignedBeaconBlock(util.HydrateSignedBeaconBlockBellatrix(blk))
 	require.NoError(t, err)
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	st := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epochsSinceFinalitySaveHotStateDB))
 	service.genesisTime = time.Now().Add(time.Duration(-1*int64(st)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)
 	r, err := bellatrixBlk.Block().HashTreeRoot()
@@ -743,14 +706,10 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	cfg := params.BeaconConfig()
 	cfg.TerminalTotalDifficulty = "2"
 	params.OverrideBeaconConfig(cfg)
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
+
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx := tr.ctx
+
 	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
 	blk := &ethpb.SignedBeaconBlockBellatrix{
 		Block: &ethpb.BeaconBlockBellatrix{
@@ -763,8 +722,6 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	}
 	bellatrixBlk, err := consensusblocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	e := &mockExecution.EngineClient{BlockByHashMap: map[[32]byte]*v1.ExecutionBlock{}}
 	e.BlockByHashMap[[32]byte{'a'}] = &v1.ExecutionBlock{
 		Header: gethtypes.Header{
@@ -786,20 +743,43 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	require.Equal(t, true, validated)
 }

-func Test_GetPayloadAttribute(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-
-	// Cache miss
-	service, err := NewService(ctx, opts...)
+func Test_reportInvalidBlock(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	params.OverrideBeaconConfig(params.MainnetConfig())
+	service, tr := minimalTestService(t)
+	ctx, _, fcs := tr.ctx, tr.db, tr.fcs
+	jcp := &ethpb.Checkpoint{}
+	st, root, err := prepareForkchoiceState(ctx, 0, [32]byte{'A'}, [32]byte{}, [32]byte{'a'}, jcp, jcp)
 	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, st, root))
+	st, root, err = prepareForkchoiceState(ctx, 1, [32]byte{'B'}, [32]byte{'A'}, [32]byte{'b'}, jcp, jcp)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, st, root))
+	st, root, err = prepareForkchoiceState(ctx, 2, [32]byte{'C'}, [32]byte{'B'}, [32]byte{'c'}, jcp, jcp)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, st, root))
+
+	st, root, err = prepareForkchoiceState(ctx, 3, [32]byte{'D'}, [32]byte{'C'}, [32]byte{'d'}, jcp, jcp)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, st, root))
+
+	require.NoError(t, fcs.SetOptimisticToValid(ctx, [32]byte{'A'}))
+	err = service.reportInvalidBlock(ctx, [32]byte{'D'}, [32]byte{'C'}, [32]byte{'a'})
+	require.Equal(t, IsInvalidBlock(err), true)
+	require.Equal(t, InvalidBlockLVH(err), [32]byte{'a'})
+	invalidRoots := InvalidAncestorRoots(err)
+	require.Equal(t, 3, len(invalidRoots))
+	require.Equal(t, [32]byte{'D'}, invalidRoots[0])
+	require.Equal(t, [32]byte{'C'}, invalidRoots[1])
+	require.Equal(t, [32]byte{'B'}, invalidRoots[2])
+}
+
+func Test_GetPayloadAttribute(t *testing.T) {
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx := tr.ctx
+
 	st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
-	hasPayload, _, vId := service.getPayloadAttribute(ctx, st, 0)
+	hasPayload, _, vId := service.getPayloadAttribute(ctx, st, 0, []byte{})
 	require.Equal(t, false, hasPayload)
 	require.Equal(t, primitives.ValidatorIndex(0), vId)

@@ -808,7 +788,7 @@ func Test_GetPayloadAttribute(t *testing.T) {
 	slot := primitives.Slot(1)
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
 	hook := logTest.NewGlobal()
-	hasPayload, attr, vId := service.getPayloadAttribute(ctx, st, slot)
+	hasPayload, attr, vId := service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
 	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedVid, vId)
 	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
@@ -818,26 +798,36 @@ func Test_GetPayloadAttribute(t *testing.T) {
 	suggestedAddr := common.HexToAddress("123")
 	require.NoError(t, service.cfg.BeaconDB.SaveFeeRecipientsByValidatorIDs(ctx, []primitives.ValidatorIndex{suggestedVid}, []common.Address{suggestedAddr}))
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
-	hasPayload, attr, vId = service.getPayloadAttribute(ctx, st, slot)
+	hasPayload, attr, vId = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
 	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedVid, vId)
 	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
 }

-func Test_GetPayloadAttributeV2(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
+func Test_GetPayloadAttribute_PrepareAllPayloads(t *testing.T) {
+	hook := logTest.NewGlobal()
+	resetCfg := features.InitWithReset(&features.Flags{
+		PrepareAllPayloads: true,
+	})
+	defer resetCfg()
+
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx := tr.ctx
+
+	st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
+	hasPayload, attr, vId := service.getPayloadAttribute(ctx, st, 0, []byte{})
+	require.Equal(t, true, hasPayload)
+	require.Equal(t, primitives.ValidatorIndex(0), vId)
+	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
+	require.LogsContain(t, hook, "Fee recipient is currently using the burn address")
+}
+
+func Test_GetPayloadAttributeV2(t *testing.T) {
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx := tr.ctx

-	// Cache miss
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	st, _ := util.DeterministicGenesisStateCapella(t, 1)
-	hasPayload, _, vId := service.getPayloadAttribute(ctx, st, 0)
+	hasPayload, _, vId := service.getPayloadAttribute(ctx, st, 0, []byte{})
 	require.Equal(t, false, hasPayload)
 	require.Equal(t, primitives.ValidatorIndex(0), vId)

@@ -846,7 +836,7 @@ func Test_GetPayloadAttributeV2(t *testing.T) {
 	slot := primitives.Slot(1)
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
 	hook := logTest.NewGlobal()
-	hasPayload, attr, vId := service.getPayloadAttribute(ctx, st, slot)
+	hasPayload, attr, vId := service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
 	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedVid, vId)
 	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
@@ -859,7 +849,7 @@ func Test_GetPayloadAttributeV2(t *testing.T) {
 	suggestedAddr := common.HexToAddress("123")
 	require.NoError(t, service.cfg.BeaconDB.SaveFeeRecipientsByValidatorIDs(ctx, []primitives.ValidatorIndex{suggestedVid}, []common.Address{suggestedAddr}))
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
-	hasPayload, attr, vId = service.getPayloadAttribute(ctx, st, slot)
+	hasPayload, attr, vId = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
 	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedVid, vId)
 	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
@@ -871,18 +861,9 @@ func Test_GetPayloadAttributeV2(t *testing.T) {
 func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	params.OverrideBeaconConfig(params.MainnetConfig())
+	service, tr := minimalTestService(t)
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	stateGen := stategen.New(beaconDB, fcs)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stateGen),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	var genesisStateRoot [32]byte
 	genesisBlk := blocks.NewGenesisBlock(genesisStateRoot[:])
 	util.SaveBlock(t, ctx, beaconDB, genesisBlk)
@@ -987,16 +968,8 @@ func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
 }

 func TestService_removeInvalidBlockAndState(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	// Deleting unknown block should not error.
 	require.NoError(t, service.removeInvalidBlockAndState(ctx, [][32]byte{{'a'}, {'b'}, {'c'}}))
@@ -1040,18 +1013,10 @@ func TestService_removeInvalidBlockAndState(t *testing.T) {
 }

 func TestService_getPayloadHash(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

-	_, err = service.getPayloadHash(ctx, []byte{})
+	_, err := service.getPayloadHash(ctx, []byte{})
 	require.ErrorIs(t, errBlockNotFoundInCacheOrDB, err)

 	b := util.NewBeaconBlock()
--- a/beacon-chain/blockchain/forkchoice_update_execution.go
+++ b/beacon-chain/blockchain/forkchoice_update_execution.go
@@ -14,11 +14,12 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 	"github.com/sirupsen/logrus"
+	"go.opencensus.io/trace"
 )

 func (s *Service) isNewProposer(slot primitives.Slot) bool {
 	_, _, ok := s.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(slot, [32]byte{} /* root */)
-	return ok
+	return ok || features.Get().PrepareAllPayloads
 }

 func (s *Service) isNewHead(r [32]byte) bool {
@@ -49,21 +50,27 @@ func (s *Service) getStateAndBlock(ctx context.Context, r [32]byte) (state.Beaco
 }

 // fockchoiceUpdateWithExecution is a wrapper around notifyForkchoiceUpdate. It decides whether a new call to FCU should be made.
-func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, newHeadRoot [32]byte, proposingSlot primitives.Slot) error {
+// it returns true if the new head is updated
+func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, newHeadRoot [32]byte, proposingSlot primitives.Slot) (bool, error) {
+	_, span := trace.StartSpan(ctx, "beacon-chain.blockchain.forkchoiceUpdateWithExecution")
+	defer span.End()
+	// Note: Use the service context here to avoid the parent context being ended during a forkchoice update.
+	ctx = trace.NewContext(s.ctx, span)
+
 	isNewHead := s.isNewHead(newHeadRoot)
 	if !isNewHead {
-		return nil
+		return false, nil
 	}
 	isNewProposer := s.isNewProposer(proposingSlot)
 	if isNewProposer && !features.Get().DisableReorgLateBlocks {
 		if s.shouldOverrideFCU(newHeadRoot, proposingSlot) {
-			return nil
+			return false, nil
 		}
 	}
 	headState, headBlock, err := s.getStateAndBlock(ctx, newHeadRoot)
 	if err != nil {
 		log.WithError(err).Error("Could not get forkchoice update argument")
-		return nil
+		return false, nil
 	}

 	_, err = s.notifyForkchoiceUpdate(ctx, &notifyForkchoiceUpdateArg{
@@ -72,7 +79,7 @@ func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, newHeadRoot
 		headBlock: headBlock.Block(),
 	})
 	if err != nil {
-		return errors.Wrap(err, "could not notify forkchoice update")
+		return false, errors.Wrap(err, "could not notify forkchoice update")
 	}

 	if err := s.saveHead(ctx, newHeadRoot, headBlock, headState); err != nil {
@@ -83,7 +90,7 @@ func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, newHeadRoot
 	if err := s.pruneAttsFromPool(headBlock); err != nil {
 		log.WithError(err).Error("could not prune attestations from pool")
 	}
-	return nil
+	return true, nil
 }

 // shouldOverrideFCU checks whether the incoming block is still subject to being
--- a/beacon-chain/blockchain/forkchoice_update_execution_test.go
+++ b/beacon-chain/blockchain/forkchoice_update_execution_test.go
@@ -8,8 +8,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
 	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
 	mockExecution "github.com/prysmaticlabs/prysm/v4/beacon-chain/execution/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
@@ -76,7 +74,8 @@ func TestService_forkchoiceUpdateWithExecution_exceptionalCases(t *testing.T) {
 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)
 	service.cfg.ProposerSlotIndexCache = cache.NewProposerPayloadIDsCache()
-	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, service.headRoot(), service.CurrentSlot()+1))
+	_, err = service.forkchoiceUpdateWithExecution(ctx, service.headRoot(), service.CurrentSlot()+1)
+	require.NoError(t, err)
 	hookErr := "could not notify forkchoice update"
 	invalidStateErr := "could not get state summary: could not find block in DB"
 	require.LogsDoNotContain(t, hook, invalidStateErr)
@@ -84,7 +83,8 @@ func TestService_forkchoiceUpdateWithExecution_exceptionalCases(t *testing.T) {
 	gb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlock())
 	require.NoError(t, err)
 	require.NoError(t, service.saveInitSyncBlock(ctx, [32]byte{'a'}, gb))
-	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, [32]byte{'a'}, service.CurrentSlot()+1))
+	_, err = service.forkchoiceUpdateWithExecution(ctx, [32]byte{'a'}, service.CurrentSlot()+1)
+	require.NoError(t, err)
 	require.LogsContain(t, hook, invalidStateErr)

 	hook.Reset()
@@ -108,7 +108,8 @@ func TestService_forkchoiceUpdateWithExecution_exceptionalCases(t *testing.T) {
 		state: st,
 	}
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(2, 1, [8]byte{1}, [32]byte{2})
-	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, r1, service.CurrentSlot()))
+	_, err = service.forkchoiceUpdateWithExecution(ctx, r1, service.CurrentSlot())
+	require.NoError(t, err)
 	require.LogsDoNotContain(t, hook, invalidStateErr)
 	require.LogsDoNotContain(t, hook, hookErr)

@@ -125,7 +126,8 @@ func TestService_forkchoiceUpdateWithExecution_exceptionalCases(t *testing.T) {
 		state: st,
 	}
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(2, 1, [8]byte{1}, [32]byte{2})
-	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, r1, service.CurrentSlot()+1))
+	_, err = service.forkchoiceUpdateWithExecution(ctx, r1, service.CurrentSlot()+1)
+	require.NoError(t, err)
 	require.LogsDoNotContain(t, hook, invalidStateErr)
 	require.LogsDoNotContain(t, hook, hookErr)
 	vId, payloadID, has := service.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(2, [32]byte{2})
@@ -135,28 +137,21 @@ func TestService_forkchoiceUpdateWithExecution_exceptionalCases(t *testing.T) {

 	// Test zero headRoot returns immediately.
 	headRoot := service.headRoot()
-	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, [32]byte{}, service.CurrentSlot()+1))
+	_, err = service.forkchoiceUpdateWithExecution(ctx, [32]byte{}, service.CurrentSlot()+1)
+	require.NoError(t, err)
 	require.Equal(t, service.headRoot(), headRoot)
 }

 func TestService_forkchoiceUpdateWithExecution_SameHeadRootNewProposer(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t)
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs
+
 	altairBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockAltair())
 	altairBlkRoot, err := altairBlk.Block().HashTreeRoot()
 	require.NoError(t, err)
 	bellatrixBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockBellatrix())
 	bellatrixBlkRoot, err := bellatrixBlk.Block().HashTreeRoot()
 	require.NoError(t, err)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	st, _ := util.DeterministicGenesisState(t, 10)
 	service.head = &head{
 		state: st,
@@ -188,24 +183,17 @@ func TestService_forkchoiceUpdateWithExecution_SameHeadRootNewProposer(t *testin
 	service.head.block = sb
 	service.head.state = st
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(service.CurrentSlot()+1, 0, [8]byte{}, [32]byte{} /* root */)
-	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, r, service.CurrentSlot()+1))
+	_, err = service.forkchoiceUpdateWithExecution(ctx, r, service.CurrentSlot()+1)
+	require.NoError(t, err)

 }

 func TestShouldOverrideFCU(t *testing.T) {
 	hook := logTest.NewGlobal()
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
+	service, tr := minimalTestService(t)
+	ctx, fcs := tr.ctx, tr.fcs
+
 	service.SetGenesisTime(time.Now().Add(-time.Duration(2*params.BeaconConfig().SecondsPerSlot) * time.Second))
-	require.NoError(t, err)
 	headRoot := [32]byte{'b'}
 	parentRoot := [32]byte{'a'}
 	ojc := &ethpb.Checkpoint{}
--- a/beacon-chain/blockchain/head.go
+++ b/beacon-chain/blockchain/head.go
@@ -47,14 +47,16 @@ func (s *Service) UpdateAndSaveHeadWithBalances(ctx context.Context) error {

 // This defines the current chain service's view of head.
 type head struct {
-	root  [32]byte                             // current head root.
-	block interfaces.ReadOnlySignedBeaconBlock // current head block.
-	state state.BeaconState                    // current head state.
+	root       [32]byte                             // current head root.
+	block      interfaces.ReadOnlySignedBeaconBlock // current head block.
+	state      state.BeaconState                    // current head state.
+	slot       primitives.Slot                      // the head block slot number
+	optimistic bool                                 // optimistic status when saved head
 }

 // This saves head info to the local service cache, it also saves the
 // new head root to the DB.
-// Caller of the method MUST aqcuire a lock on forkchoice.
+// Caller of the method MUST acquire a lock on forkchoice.
 func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock interfaces.ReadOnlySignedBeaconBlock, headState state.BeaconState) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.saveHead")
 	defer span.End()
@@ -89,13 +91,17 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 	newHeadSlot := headBlock.Block().Slot()
 	newStateRoot := headBlock.Block().StateRoot()

-	// A chain re-org occurred, so we fire an event notifying the rest of the services.
 	r, err := s.HeadRoot(ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not get old head root")
 	}
 	oldHeadRoot := bytesutil.ToBytes32(r)
+	isOptimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(newHeadRoot)
+	if err != nil {
+		log.WithError(err).Error("could not check if node is optimistically synced")
+	}
 	if headBlock.Block().ParentRoot() != oldHeadRoot {
+		// A chain re-org occurred, so we fire an event notifying the rest of the services.
 		commonRoot, forkSlot, err := s.cfg.ForkChoiceStore.CommonAncestor(ctx, oldHeadRoot, newHeadRoot)
 		if err != nil {
 			log.WithError(err).Error("Could not find common ancestor root")
@@ -125,10 +131,6 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 		reorgDistance.Observe(float64(dis))
 		reorgDepth.Observe(float64(dep))

-		isOptimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(newHeadRoot)
-		if err != nil {
-			return errors.Wrap(err, "could not check if node is optimistically synced")
-		}
 		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.Reorg,
 			Data: &ethpbv1.EventChainReorg{
@@ -150,7 +152,14 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 	}

 	// Cache the new head info.
-	if err := s.setHead(newHeadRoot, headBlock, headState); err != nil {
+	newHead := &head{
+		root:       newHeadRoot,
+		block:      headBlock,
+		state:      headState,
+		optimistic: isOptimistic,
+		slot:       headBlock.Block().Slot(),
+	}
+	if err := s.setHead(newHead); err != nil {
 		return errors.Wrap(err, "could not set head")
 	}

@@ -195,20 +204,22 @@ func (s *Service) saveHeadNoDB(ctx context.Context, b interfaces.ReadOnlySignedB
 	return nil
 }

-// 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 interfaces.ReadOnlySignedBeaconBlock, state state.BeaconState) error {
+// This sets head view object which is used to track the head slot, root, block, state and optimistic status
+func (s *Service) setHead(newHead *head) error {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

 	// This does a full copy of the block and state.
-	bCp, err := block.Copy()
+	bCp, err := newHead.block.Copy()
 	if err != nil {
 		return err
 	}
 	s.head = &head{
-		root:  root,
-		block: bCp,
-		state: state.Copy(),
+		root:       newHead.root,
+		block:      bCp,
+		state:      newHead.state.Copy(),
+		optimistic: newHead.optimistic,
+		slot:       newHead.slot,
 	}
 	return nil
 }
@@ -403,6 +414,19 @@ func (s *Service) saveOrphanedOperations(ctx context.Context, orphanedRoot [32]b
 			}
 			saveOrphanedAttCount.Inc()
 		}
+		for _, as := range orphanedBlk.Block().Body().AttesterSlashings() {
+			if err := s.cfg.SlashingPool.InsertAttesterSlashing(ctx, s.headStateReadOnly(ctx), as); err != nil {
+				log.WithError(err).Error("Could not insert reorg attester slashing")
+			}
+		}
+		for _, vs := range orphanedBlk.Block().Body().ProposerSlashings() {
+			if err := s.cfg.SlashingPool.InsertProposerSlashing(ctx, s.headStateReadOnly(ctx), vs); err != nil {
+				log.WithError(err).Error("Could not insert reorg proposer slashing")
+			}
+		}
+		for _, v := range orphanedBlk.Block().Body().VoluntaryExits() {
+			s.cfg.ExitPool.InsertVoluntaryExit(v)
+		}
 		if orphanedBlk.Version() >= version.Capella {
 			changes, err := orphanedBlk.Block().Body().BLSToExecutionChanges()
 			if err != nil {
--- a/beacon-chain/blockchain/head_sync_committee_info.go
+++ b/beacon-chain/blockchain/head_sync_committee_info.go
@@ -53,7 +53,7 @@ func (s *Service) HeadSyncContributionProofDomain(ctx context.Context, slot prim

 // 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.
+// across EPOCHS_PER_SYNC_COMMITTEE_PERIOD then the validator 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.
@@ -157,7 +157,11 @@ func (s *Service) getSyncCommitteeHeadState(ctx context.Context, slot primitives
 		if headState == nil || headState.IsNil() {
 			return nil, errors.New("nil state")
 		}
-		headState, err = transition.ProcessSlotsIfPossible(ctx, headState, slot)
+		headRoot, err := s.HeadRoot(ctx)
+		if err != nil {
+			return nil, err
+		}
+		headState, err = transition.ProcessSlotsUsingNextSlotCache(ctx, headState, headRoot, slot)
 		if err != nil {
 			return nil, err
 		}
--- a/beacon-chain/blockchain/head_sync_committee_info_test.go
+++ b/beacon-chain/blockchain/head_sync_committee_info_test.go
@@ -6,6 +6,7 @@ import (

 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/signing"
+	dbTest "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v4/testing/require"
@@ -15,7 +16,7 @@ import (

 func TestService_HeadSyncCommitteeIndices(t *testing.T) {
 	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
+	c := &Service{cfg: &config{BeaconDB: dbTest.SetupDB(t)}}
 	c.head = &head{state: s}

 	// Current period
@@ -38,7 +39,7 @@ func TestService_HeadSyncCommitteeIndices(t *testing.T) {

 func TestService_headCurrentSyncCommitteeIndices(t *testing.T) {
 	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
+	c := &Service{cfg: &config{BeaconDB: dbTest.SetupDB(t)}}
 	c.head = &head{state: s}

 	// Process slot up to `EpochsPerSyncCommitteePeriod` so it can `ProcessSyncCommitteeUpdates`.
@@ -66,7 +67,7 @@ func TestService_headNextSyncCommitteeIndices(t *testing.T) {

 func TestService_HeadSyncCommitteePubKeys(t *testing.T) {
 	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
+	c := &Service{cfg: &config{BeaconDB: dbTest.SetupDB(t)}}
 	c.head = &head{state: s}

 	// Process slot up to 2 * `EpochsPerSyncCommitteePeriod` so it can run `ProcessSyncCommitteeUpdates` twice.
@@ -81,7 +82,7 @@ func TestService_HeadSyncCommitteePubKeys(t *testing.T) {

 func TestService_HeadSyncCommitteeDomain(t *testing.T) {
 	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
-	c := &Service{}
+	c := &Service{cfg: &config{BeaconDB: dbTest.SetupDB(t)}}
 	c.head = &head{state: s}

 	wanted, err := signing.Domain(s.Fork(), slots.ToEpoch(s.Slot()), params.BeaconConfig().DomainSyncCommittee, s.GenesisValidatorsRoot())
--- a/beacon-chain/blockchain/head_test.go
+++ b/beacon-chain/blockchain/head_test.go
@@ -9,10 +9,8 @@ import (

 	mock "github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain/testing"
 	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/blstoexec"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
@@ -326,6 +324,88 @@ func TestSaveOrphanedAtts(t *testing.T) {
 	require.DeepEqual(t, wantAtts, atts)
 }

+func TestSaveOrphanedOps(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	config := params.BeaconConfig()
+	config.ShardCommitteePeriod = 0
+	params.OverrideBeaconConfig(config)
+
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+	service.genesisTime = time.Now().Add(time.Duration(-10*int64(1)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)
+
+	// Chain setup
+	// 0 -- 1 -- 2 -- 3
+	//  \-4
+	st, keys := util.DeterministicGenesisState(t, 64)
+	service.head = &head{state: st}
+	blkG, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 0)
+	assert.NoError(t, err)
+
+	util.SaveBlock(t, ctx, service.cfg.BeaconDB, blkG)
+	rG, err := blkG.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blk1, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 1)
+	assert.NoError(t, err)
+	blk1.Block.ParentRoot = rG[:]
+	r1, err := blk1.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blk2, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 2)
+	assert.NoError(t, err)
+	blk2.Block.ParentRoot = r1[:]
+	r2, err := blk2.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blkConfig := util.DefaultBlockGenConfig()
+	blkConfig.NumBLSChanges = 5
+	blkConfig.NumProposerSlashings = 1
+	blkConfig.NumAttesterSlashings = 1
+	blkConfig.NumVoluntaryExits = 1
+	blk3, err := util.GenerateFullBlock(st, keys, blkConfig, 3)
+	assert.NoError(t, err)
+	blk3.Block.ParentRoot = r2[:]
+	r3, err := blk3.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	blk4 := util.NewBeaconBlock()
+	blk4.Block.Slot = 4
+	blk4.Block.ParentRoot = rG[:]
+	r4, err := blk4.Block.HashTreeRoot()
+	require.NoError(t, err)
+	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+
+	for _, blk := range []*ethpb.SignedBeaconBlock{blkG, blk1, blk2, blk3, blk4} {
+		r, err := blk.Block.HashTreeRoot()
+		require.NoError(t, err)
+		state, blkRoot, err := prepareForkchoiceState(ctx, blk.Block.Slot, r, bytesutil.ToBytes32(blk.Block.ParentRoot), [32]byte{}, ojc, ofc)
+		require.NoError(t, err)
+		require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
+		util.SaveBlock(t, ctx, beaconDB, blk)
+	}
+
+	require.NoError(t, service.saveOrphanedOperations(ctx, r3, r4))
+	require.Equal(t, 3, service.cfg.AttPool.AggregatedAttestationCount())
+	wantAtts := []*ethpb.Attestation{
+		blk3.Block.Body.Attestations[0],
+		blk2.Block.Body.Attestations[0],
+		blk1.Block.Body.Attestations[0],
+	}
+	atts := service.cfg.AttPool.AggregatedAttestations()
+	sort.Slice(atts, func(i, j int) bool {
+		return atts[i].Data.Slot > atts[j].Data.Slot
+	})
+	require.DeepEqual(t, wantAtts, atts)
+	require.Equal(t, 1, len(service.cfg.SlashingPool.PendingProposerSlashings(ctx, st, false)))
+	require.Equal(t, 1, len(service.cfg.SlashingPool.PendingAttesterSlashings(ctx, st, false)))
+	exits, err := service.cfg.ExitPool.PendingExits()
+	require.NoError(t, err)
+	require.Equal(t, 1, len(exits))
+}
+
 func TestSaveOrphanedAtts_CanFilter(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
@@ -499,18 +579,9 @@ func TestSaveOrphanedAtts_CanFilter_DoublyLinkedTrie(t *testing.T) {
 }

 func TestUpdateHead_noSavedChanges(t *testing.T) {
-	ctx := context.Background()
+	service, tr := minimalTestService(t)
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs

-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	ojp := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	st, blkRoot, err := prepareForkchoiceState(ctx, 0, [32]byte{}, [32]byte{}, [32]byte{}, ojp, ojp)
 	require.NoError(t, err)
--- a/beacon-chain/blockchain/log.go
+++ b/beacon-chain/blockchain/log.go
@@ -8,7 +8,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
-	consensusBlocks "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	consensus_types "github.com/prysmaticlabs/prysm/v4/consensus-types"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
@@ -53,14 +53,13 @@ func logStateTransitionData(b interfaces.ReadOnlyBeaconBlock) error {
 		log = log.WithField("payloadHash", fmt.Sprintf("%#x", bytesutil.Trunc(p.BlockHash())))
 		txs, err := p.Transactions()
 		switch {
-		case errors.Is(err, consensusBlocks.ErrUnsupportedGetter):
+		case errors.Is(err, consensus_types.ErrUnsupportedField):
 		case err != nil:
 			return err
 		default:
 			log = log.WithField("txCount", len(txs))
 			txsPerSlotCount.Set(float64(len(txs)))
 		}
-
 	}
 	log.Info("Finished applying state transition")
 	return nil
@@ -121,7 +120,7 @@ func logPayload(block interfaces.ReadOnlyBeaconBlock) error {
 	fields := logrus.Fields{
 		"blockHash":   fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash())),
 		"parentHash":  fmt.Sprintf("%#x", bytesutil.Trunc(payload.ParentHash())),
-		"blockNumber": payload.BlockNumber,
+		"blockNumber": payload.BlockNumber(),
 		"gasUtilized": fmt.Sprintf("%.2f", gasUtilized),
 	}
 	if block.Version() >= version.Capella {
--- a/beacon-chain/blockchain/mock_test.go
+++ b/beacon-chain/blockchain/mock_test.go
@@ -5,16 +5,19 @@ import (

 	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/startup"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 )

 func testServiceOptsWithDB(t *testing.T) []Option {
 	beaconDB := testDB.SetupDB(t)
 	fcs := doublylinkedtree.New()
+	cs := startup.NewClockSynchronizer()
 	return []Option{
 		WithDatabase(beaconDB),
 		WithStateGen(stategen.New(beaconDB, fcs)),
 		WithForkChoiceStore(fcs),
+		WithClockSynchronizer(cs),
 	}
 }

@@ -22,5 +25,6 @@ func testServiceOptsWithDB(t *testing.T) []Option {
 // 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{}
+	cs := startup.NewClockSynchronizer()
+	return []Option{WithClockSynchronizer(cs)}
 }
--- a/beacon-chain/blockchain/options.go
+++ b/beacon-chain/blockchain/options.go
@@ -13,6 +13,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/slashings"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/p2p"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/startup"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
@@ -163,3 +164,18 @@ func WithFinalizedStateAtStartUp(st state.BeaconState) Option {
 		return nil
 	}
 }
+
+func WithClockSynchronizer(gs *startup.ClockSynchronizer) Option {
+	return func(s *Service) error {
+		s.clockSetter = gs
+		s.clockWaiter = gs
+		return nil
+	}
+}
+
+func WithSyncComplete(c chan struct{}) Option {
+	return func(s *Service) error {
+		s.syncComplete = c
+		return nil
+	}
+}
--- a/beacon-chain/blockchain/pow_block_test.go
+++ b/beacon-chain/blockchain/pow_block_test.go
@@ -1,17 +1,13 @@
 package blockchain

 import (
-	"context"
 	"fmt"
 	"math/big"
 	"testing"

 	gethtypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/holiman/uint256"
-	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
 	mocks "github.com/prysmaticlabs/prysm/v4/beacon-chain/execution/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
@@ -108,16 +104,8 @@ func Test_validateMergeBlock(t *testing.T) {
 	cfg.TerminalTotalDifficulty = "2"
 	params.OverrideBeaconConfig(cfg)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	engine := &mocks.EngineClient{BlockByHashMap: map[[32]byte]*enginev1.ExecutionBlock{}}
 	service.cfg.ExecutionEngineCaller = engine
@@ -158,16 +146,8 @@ func Test_validateMergeBlock(t *testing.T) {
 }

 func Test_getBlkParentHashAndTD(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	engine := &mocks.EngineClient{BlockByHashMap: map[[32]byte]*enginev1.ExecutionBlock{}}
 	service.cfg.ExecutionEngineCaller = engine
@@ -239,14 +219,9 @@ func Test_validateTerminalBlockHash(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, true, ok)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+
 	blk, err := blocks.NewSignedBeaconBlock(util.HydrateSignedBeaconBlockBellatrix(&ethpb.SignedBeaconBlockBellatrix{}))
 	require.NoError(t, err)
 	blk.SetSlot(1)
--- a/beacon-chain/blockchain/process_attestation_helpers.go
+++ b/beacon-chain/blockchain/process_attestation_helpers.go
@@ -8,6 +8,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/async"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
@@ -18,7 +19,17 @@ import (
 )

 // 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) (state.ReadOnlyBeaconState, error) {
+	// If the attestation is recent and canonical we can use the head state to compute the shuffling.
+	headEpoch := slots.ToEpoch(s.HeadSlot())
+	if c.Epoch == headEpoch {
+		targetSlot, err := s.cfg.ForkChoiceStore.Slot([32]byte(c.Root))
+		if err == nil && slots.ToEpoch(targetSlot)+1 >= headEpoch {
+			if s.cfg.ForkChoiceStore.IsCanonical([32]byte(c.Root)) {
+				return s.HeadStateReadOnly(ctx)
+			}
+		}
+	}
 	// 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 */)
@@ -32,7 +43,36 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (stat
 	if cachedState != nil && !cachedState.IsNil() {
 		return cachedState, nil
 	}
+	// Try the next slot cache for the early epoch calls, this should mostly have been covered already
+	// but is cheap
+	slot, err := slots.EpochStart(c.Epoch)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not compute epoch start")
+	}
+	cachedState = transition.NextSlotState(c.Root, slot)
+	if cachedState != nil && !cachedState.IsNil() {
+		if cachedState.Slot() != slot {
+			cachedState, err = transition.ProcessSlots(ctx, cachedState, slot)
+			if err != nil {
+				return nil, errors.Wrap(err, "could not process slots")
+			}
+		}
+		if err := s.checkpointStateCache.AddCheckpointState(c, cachedState); err != nil {
+			return nil, errors.Wrap(err, "could not save checkpoint state to cache")
+		}
+		return cachedState, nil
+	}

+	// Do not process attestations for old non viable checkpoints otherwise
+	ok, err := s.cfg.ForkChoiceStore.IsViableForCheckpoint(&forkchoicetypes.Checkpoint{Root: [32]byte(c.Root), Epoch: c.Epoch})
+	if err != nil {
+		return nil, errors.Wrap(err, "could not check checkpoint condition in forkchoice")
+	}
+	if !ok {
+		return nil, errors.Wrap(ErrNotCheckpoint, fmt.Sprintf("epoch %d root %#x", c.Epoch, c.Root))
+	}
+
+	// Fallback to state regeneration.
 	baseState, err := s.cfg.StateGen.StateByRoot(ctx, bytesutil.ToBytes32(c.Root))
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not get pre state for epoch %d", c.Epoch)
@@ -55,7 +95,6 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (stat
 		return nil, errors.Wrap(err, "could not save checkpoint state to cache")
 	}
 	return baseState, nil
-
 }

 // verifyAttTargetEpoch validates attestation is from the current or previous epoch.
--- a/beacon-chain/blockchain/process_attestation_test.go
+++ b/beacon-chain/blockchain/process_attestation_test.go
@@ -6,9 +6,6 @@ import (
 	"time"

 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
-	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
@@ -21,29 +18,29 @@ import (
 )

 func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(fc),
-		WithStateGen(stategen.New(beaconDB, fc)),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	_, err = blockTree1(t, beaconDB, []byte{'g'})
+	_, err := blockTree1(t, beaconDB, []byte{'g'})
 	require.NoError(t, err)

 	blkWithoutState := util.NewBeaconBlock()
 	blkWithoutState.Block.Slot = 0
 	util.SaveBlock(t, ctx, beaconDB, blkWithoutState)
-	BlkWithOutStateRoot, err := blkWithoutState.Block.HashTreeRoot()
+
+	cp := &ethpb.Checkpoint{}
+	st, blkRoot, err := prepareForkchoiceState(ctx, 0, [32]byte{}, [32]byte{}, params.BeaconConfig().ZeroHash, cp, cp)
 	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blkRoot))

 	blkWithStateBadAtt := util.NewBeaconBlock()
 	blkWithStateBadAtt.Block.Slot = 1
+	r, err := blkWithStateBadAtt.Block.HashTreeRoot()
+	require.NoError(t, err)
+	cp = &ethpb.Checkpoint{Root: r[:]}
+	st, blkRoot, err = prepareForkchoiceState(ctx, blkWithStateBadAtt.Block.Slot, r, [32]byte{}, params.BeaconConfig().ZeroHash, cp, cp)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blkRoot))
 	util.SaveBlock(t, ctx, beaconDB, blkWithStateBadAtt)
 	BlkWithStateBadAttRoot, err := blkWithStateBadAtt.Block.HashTreeRoot()
 	require.NoError(t, err)
@@ -54,7 +51,7 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot))

 	blkWithValidState := util.NewBeaconBlock()
-	blkWithValidState.Block.Slot = 2
+	blkWithValidState.Block.Slot = 32
 	util.SaveBlock(t, ctx, beaconDB, blkWithValidState)

 	blkWithValidStateRoot, err := blkWithValidState.Block.HashTreeRoot()
@@ -69,6 +66,10 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, blkWithValidStateRoot))

+	service.head = &head{
+		state: st,
+	}
+
 	tests := []struct {
 		name      string
 		a         *ethpb.Attestation
@@ -79,11 +80,6 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 			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,
@@ -128,17 +124,9 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 }

 func TestStore_OnAttestation_Ok_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		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))
@@ -158,15 +146,8 @@ func TestStore_OnAttestation_Ok_DoublyLinkedTree(t *testing.T) {
 }

 func TestStore_SaveCheckpointState(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	s, err := util.NewBeaconState()
 	require.NoError(t, err)
@@ -187,6 +168,9 @@ func TestStore_SaveCheckpointState(t *testing.T) {
 	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)}))

+	st, root, err := prepareForkchoiceState(ctx, 1, [32]byte(cp1.Root), [32]byte{}, [32]byte{'R'}, cp1, cp1)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, root))
 	s1, err := service.getAttPreState(ctx, cp1)
 	require.NoError(t, err)
 	assert.Equal(t, 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot(), "Unexpected state slot")
@@ -194,8 +178,17 @@ func TestStore_SaveCheckpointState(t *testing.T) {
 	cp2 := &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'B'}, fieldparams.RootLength)}
 	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)}))
+
 	s2, err := service.getAttPreState(ctx, cp2)
+	require.ErrorContains(t, "epoch 2 root 0x4200000000000000000000000000000000000000000000000000000000000000: not a checkpoint in forkchoice", err)
+
+	st, root, err = prepareForkchoiceState(ctx, 33, [32]byte(cp2.Root), [32]byte(cp1.Root), [32]byte{'R'}, cp2, cp2)
 	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, root))
+
+	s2, err = service.getAttPreState(ctx, cp2)
+	require.NoError(t, err)
+
 	assert.Equal(t, 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot(), "Unexpected state slot")

 	s1, err = service.getAttPreState(ctx, cp1)
@@ -214,26 +207,30 @@ func TestStore_SaveCheckpointState(t *testing.T) {
 	cp3 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'C'}, fieldparams.RootLength)}
 	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)}))
+	st, root, err = prepareForkchoiceState(ctx, 31, [32]byte(cp3.Root), [32]byte(cp2.Root), [32]byte{'P'}, cp2, cp2)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, root))
+
 	s3, err := service.getAttPreState(ctx, cp3)
 	require.NoError(t, err)
 	assert.Equal(t, s.Slot(), s3.Slot(), "Unexpected state slot")
 }

 func TestStore_UpdateCheckpointState(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+	baseState, _ := util.DeterministicGenesisState(t, 1)

 	epoch := primitives.Epoch(1)
-	baseState, _ := util.DeterministicGenesisState(t, 1)
-	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("hi"), fieldparams.RootLength)}
+	blk := util.NewBeaconBlock()
+	r1, err := blk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: r1[:]}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)))
+	st, blkRoot, err := prepareForkchoiceState(ctx, blk.Block.Slot, r1, [32]byte{}, params.BeaconConfig().ZeroHash, checkpoint, checkpoint)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blkRoot))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, r1))
 	returned, err := service.getAttPreState(ctx, checkpoint)
 	require.NoError(t, err)
 	assert.Equal(t, params.BeaconConfig().SlotsPerEpoch.Mul(uint64(checkpoint.Epoch)), returned.Slot(), "Incorrectly returned base state")
@@ -243,8 +240,16 @@ 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)}
+	blk = util.NewBeaconBlock()
+	blk.Block.Slot = 64
+	r2, err := blk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	newCheckpoint := &ethpb.Checkpoint{Epoch: epoch, Root: r2[:]}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(newCheckpoint.Root)))
+	st, blkRoot, err = prepareForkchoiceState(ctx, blk.Block.Slot, r2, r1, params.BeaconConfig().ZeroHash, newCheckpoint, newCheckpoint)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, blkRoot))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, st, r2))
 	returned, err = service.getAttPreState(ctx, newCheckpoint)
 	require.NoError(t, err)
 	s, err := slots.EpochStart(newCheckpoint.Epoch)
@@ -323,3 +328,22 @@ func TestVerifyBeaconBlock_OK(t *testing.T) {

 	assert.NoError(t, service.verifyBeaconBlock(ctx, d), "Did not receive the wanted error")
 }
+
+func TestGetAttPreState_HeadState(t *testing.T) {
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx
+	baseState, _ := util.DeterministicGenesisState(t, 1)
+
+	epoch := primitives.Epoch(1)
+	blk := util.NewBeaconBlock()
+	r1, err := blk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: r1[:]}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)))
+	require.NoError(t, transition.UpdateNextSlotCache(ctx, checkpoint.Root, baseState))
+	_, err = service.getAttPreState(ctx, checkpoint)
+	require.NoError(t, err)
+	st, err := service.checkpointStateCache.StateByCheckpoint(checkpoint)
+	require.NoError(t, err)
+	require.Equal(t, params.BeaconConfig().SlotsPerEpoch, st.Slot())
+}
--- a/beacon-chain/blockchain/process_block.go
+++ b/beacon-chain/blockchain/process_block.go
@@ -6,7 +6,6 @@ import (
 	"time"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v4/async/event"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed/state"
@@ -108,7 +107,8 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 	}

 	// Verify that the parent block is in forkchoice
-	if !s.cfg.ForkChoiceStore.HasNode(b.ParentRoot()) {
+	parentRoot := b.ParentRoot()
+	if !s.cfg.ForkChoiceStore.HasNode(parentRoot) {
 		return ErrNotDescendantOfFinalized
 	}

@@ -135,18 +135,21 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 	}
 	isValidPayload, err := s.notifyNewPayload(ctx, postStateVersion, postStateHeader, signed)
 	if err != nil {
+		if IsInvalidBlock(err) && InvalidBlockLVH(err) != [32]byte{} {
+			return s.reportInvalidBlock(ctx, blockRoot, parentRoot, InvalidBlockLVH(err))
+		}
 		return errors.Wrap(err, "could not validate new payload")
 	}
-	if isValidPayload {
+	if signed.Version() < version.Capella && isValidPayload {
 		if err := s.validateMergeTransitionBlock(ctx, preStateVersion, preStateHeader, signed); err != nil {
 			return err
 		}
 	}
+
 	if err := s.savePostStateInfo(ctx, blockRoot, signed, postState); err != nil {
 		return err
 	}
-
-	if err := s.insertBlockToForkchoiceStore(ctx, signed.Block(), blockRoot, postState); err != nil {
+	if err := s.cfg.ForkChoiceStore.InsertNode(ctx, postState, blockRoot); err != nil {
 		return errors.Wrapf(err, "could not insert block %d to fork choice store", signed.Block().Slot())
 	}
 	if err := s.handleBlockAttestations(ctx, signed.Block(), postState); err != nil {
@@ -186,7 +189,6 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 			}
 		}()
 	}
-
 	justified := s.cfg.ForkChoiceStore.JustifiedCheckpoint()
 	start := time.Now()
 	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx)
@@ -208,12 +210,24 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 			"headRoot":       fmt.Sprintf("%#x", headRoot),
 			"headWeight":     headWeight,
 		}).Debug("Head block is not the received block")
+	} else {
+		// 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")
+			}
+		}()
 	}
 	newBlockHeadElapsedTime.Observe(float64(time.Since(start).Milliseconds()))

 	// verify conditions for FCU, notifies FCU, and saves the new head.
 	// This function also prunes attestations, other similar operations happen in prunePostBlockOperationPools.
-	if err := s.forkchoiceUpdateWithExecution(ctx, headRoot, s.CurrentSlot()+1); err != nil {
+	if _, err := s.forkchoiceUpdateWithExecution(ctx, headRoot, s.CurrentSlot()+1); err != nil {
 		return err
 	}

@@ -228,18 +242,6 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 		},
 	})

-	// 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")
-		}
-	}()
-
 	// Save justified check point to db.
 	postStateJustifiedEpoch := postState.CurrentJustifiedCheckpoint().Epoch
 	if justified.Epoch > currStoreJustifiedEpoch || (justified.Epoch == postStateJustifiedEpoch && justified.Epoch > preStateJustifiedEpoch) {
@@ -257,10 +259,6 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 		if err := s.updateFinalized(ctx, &ethpb.Checkpoint{Epoch: finalized.Epoch, Root: finalized.Root[:]}); err != nil {
 			return err
 		}
-		isOptimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(finalized.Root)
-		if err != nil {
-			return errors.Wrap(err, "could not check if node is optimistically synced")
-		}
 		go func() {
 			// Send an event regarding the new finalized checkpoint over a common event feed.
 			stateRoot := signed.Block().StateRoot()
@@ -270,7 +268,7 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 					Epoch:               postState.FinalizedCheckpoint().Epoch,
 					Block:               postState.FinalizedCheckpoint().Root,
 					State:               stateRoot[:],
-					ExecutionOptimistic: isOptimistic,
+					ExecutionOptimistic: isValidPayload,
 				},
 			})

@@ -283,10 +281,9 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 				log.WithError(err).Error("Could not insert finalized deposits.")
 			}
 		}()
-
 	}
 	defer reportAttestationInclusion(b)
-	if err := s.handleEpochBoundary(ctx, postState); err != nil {
+	if err := s.handleEpochBoundary(ctx, postState, blockRoot[:]); err != nil {
 		return err
 	}
 	onBlockProcessingTime.Observe(float64(time.Since(startTime).Milliseconds()))
@@ -484,14 +481,14 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.ReadOnlySi
 }

 // Epoch boundary bookkeeping such as logging epoch summaries.
-func (s *Service) handleEpochBoundary(ctx context.Context, postState state.BeaconState) error {
+func (s *Service) handleEpochBoundary(ctx context.Context, postState state.BeaconState, blockRoot []byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.handleEpochBoundary")
 	defer span.End()

 	var err error
 	if postState.Slot()+1 == s.nextEpochBoundarySlot {
 		copied := postState.Copy()
-		copied, err := transition.ProcessSlots(ctx, copied, copied.Slot()+1)
+		copied, err := transition.ProcessSlotsUsingNextSlotCache(ctx, copied, blockRoot, copied.Slot()+1)
 		if err != nil {
 			return err
 		}
@@ -499,10 +496,32 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco
 		if err := helpers.UpdateCommitteeCache(ctx, copied, coreTime.CurrentEpoch(copied)); err != nil {
 			return err
 		}
-		if err := helpers.UpdateProposerIndicesInCache(ctx, copied); err != nil {
+		e := coreTime.CurrentEpoch(copied)
+		if err := helpers.UpdateProposerIndicesInCache(ctx, copied, e); err != nil {
 			return err
 		}
+		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 := helpers.UpdateProposerIndicesInCache(slotCtx, copied, e+1); err != nil {
+				log.WithError(err).Warn("Failed to cache next epoch proposers")
+			}
+		}()
 	} else if postState.Slot() >= s.nextEpochBoundarySlot {
+		postState = postState.Copy()
+		if s.nextEpochBoundarySlot != 0 {
+			ep := slots.ToEpoch(s.nextEpochBoundarySlot)
+			_, nextProposerIndexToSlots, err := helpers.CommitteeAssignments(ctx, postState, ep)
+			if err != nil {
+				return err
+			}
+			for k, v := range nextProposerIndexToSlots {
+				s.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(v[0], k, [8]byte{}, [32]byte{})
+			}
+		}
 		s.nextEpochBoundarySlot, err = slots.EpochStart(coreTime.NextEpoch(postState))
 		if err != nil {
 			return err
@@ -513,7 +532,7 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco
 		if err := helpers.UpdateCommitteeCache(ctx, postState, coreTime.CurrentEpoch(postState)); err != nil {
 			return err
 		}
-		if err := helpers.UpdateProposerIndicesInCache(ctx, postState); err != nil {
+		if err := helpers.UpdateProposerIndicesInCache(ctx, postState, coreTime.CurrentEpoch(postState)); err != nil {
 			return err
 		}

@@ -525,27 +544,9 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco
 			return err
 		}
 	}
-
 	return nil
 }

-// This feeds in the block to fork choice store. It's allows fork choice store
-// to gain information on the most current chain.
-func (s *Service) insertBlockToForkchoiceStore(ctx context.Context, blk interfaces.ReadOnlyBeaconBlock, root [32]byte, st state.BeaconState) error {
-	ctx, span := trace.StartSpan(ctx, "blockChain.insertBlockToForkchoiceStore")
-	defer span.End()
-
-	if !s.cfg.ForkChoiceStore.HasNode(blk.ParentRoot()) {
-		fCheckpoint := st.FinalizedCheckpoint()
-		jCheckpoint := st.CurrentJustifiedCheckpoint()
-		if err := s.fillInForkChoiceMissingBlocks(ctx, blk, fCheckpoint, jCheckpoint); err != nil {
-			return err
-		}
-	}
-
-	return s.cfg.ForkChoiceStore.InsertNode(ctx, st, root)
-}
-
 // This feeds in the attestations included in the block to fork choice store. It's allows fork choice store
 // to gain information on the most current chain.
 func (s *Service) handleBlockAttestations(ctx context.Context, blk interfaces.ReadOnlyBeaconBlock, st state.BeaconState) error {
@@ -652,66 +653,81 @@ func (s *Service) validateMergeTransitionBlock(ctx context.Context, stateVersion

 // This routine checks if there is a cached proposer payload ID available for the next slot proposer.
 // If there is not, it will call forkchoice updated with the correct payload attribute then cache the payload ID.
-func (s *Service) fillMissingPayloadIDRoutine(ctx context.Context, stateFeed *event.Feed) {
-	// Wait for state to be initialized.
-	stateChannel := make(chan *feed.Event, 1)
-	stateSub := stateFeed.Subscribe(stateChannel)
-	go func() {
+func (s *Service) runLateBlockTasks() {
+	if err := s.waitForSync(); err != nil {
+		log.WithError(err).Error("failed to wait for initial sync")
+		return
+	}
+
+	attThreshold := params.BeaconConfig().SecondsPerSlot / 3
+	ticker := slots.NewSlotTickerWithOffset(s.genesisTime, time.Duration(attThreshold)*time.Second, params.BeaconConfig().SecondsPerSlot)
+	for {
 		select {
+		case <-ticker.C():
+			s.lateBlockTasks(s.ctx)
 		case <-s.ctx.Done():
-			stateSub.Unsubscribe()
+			log.Debug("Context closed, exiting routine")
 			return
-		case <-stateChannel:
-			stateSub.Unsubscribe()
-			break
 		}
-
-		attThreshold := params.BeaconConfig().SecondsPerSlot / 3
-		ticker := slots.NewSlotTickerWithOffset(s.genesisTime, time.Duration(attThreshold)*time.Second, params.BeaconConfig().SecondsPerSlot)
-		for {
-			select {
-			case <-ticker.C():
-				if err := s.fillMissingBlockPayloadId(ctx); err != nil {
-					log.WithError(err).Error("Could not fill missing payload ID")
-				}
-
-			case <-ctx.Done():
-				log.Debug("Context closed, exiting routine")
-				return
-			}
-		}
-	}()
+	}
 }

-// fillMissingBlockPayloadId is called 4 seconds into the slot and calls FCU if we are proposing next slot
-// and the cache has been missed
-func (s *Service) fillMissingBlockPayloadId(ctx context.Context) error {
+// lateBlockTasks  is called 4 seconds into the slot and performs tasks
+// related to late blocks. It emits a MissedSlot state feed event.
+// It calls FCU and sets the right attributes if we are proposing next slot
+// it also updates the next slot cache to deal with skipped slots.
+func (s *Service) lateBlockTasks(ctx context.Context) {
 	if s.CurrentSlot() == s.HeadSlot() {
-		return nil
+		return
 	}
 	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 		Type: statefeed.MissedSlot,
 	})

+	headRoot := s.headRoot()
+	headState := s.headState(ctx)
+	lastRoot, lastState := transition.LastCachedState()
+	if lastState == nil {
+		lastRoot, lastState = headRoot[:], headState
+	}
+	// Copy all the field tries in our cached state in the event of late
+	// blocks.
+	lastState.CopyAllTries()
+	if err := transition.UpdateNextSlotCache(ctx, lastRoot, lastState); err != nil {
+		log.WithError(err).Debug("could not update next slot state cache")
+	}
+
 	// Head root should be empty when retrieving proposer index for the next slot.
 	_, id, has := s.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(s.CurrentSlot()+1, [32]byte{} /* head root */)
 	// There exists proposer for next slot, but we haven't called fcu w/ payload attribute yet.
-	if !has || id != [8]byte{} {
-		return nil
+	if (!has && !features.Get().PrepareAllPayloads) || id != [8]byte{} {
+		return
 	}
+
 	s.headLock.RLock()
 	headBlock, err := s.headBlock()
 	if err != nil {
 		s.headLock.RUnlock()
-		return err
+		log.WithError(err).Debug("could not perform late block tasks: failed to retrieve head block")
+		return
 	}
-	headState := s.headState(ctx)
-	headRoot := s.headRoot()
 	s.headLock.RUnlock()
 	_, err = s.notifyForkchoiceUpdate(ctx, &notifyForkchoiceUpdateArg{
 		headState: headState,
 		headRoot:  headRoot,
 		headBlock: headBlock.Block(),
 	})
-	return err
+	if err != nil {
+		log.WithError(err).Debug("could not perform late block tasks: failed to update forkchoice with engine")
+	}
+}
+
+// waitForSync blocks until the node is synced to the head.
+func (s *Service) waitForSync() error {
+	select {
+	case <-s.syncComplete:
+		return nil
+	case <-s.ctx.Done():
+		return errors.New("context closed, exiting goroutine")
+	}
 }
--- a/beacon-chain/blockchain/process_block_helpers.go
+++ b/beacon-chain/blockchain/process_block_helpers.go
@@ -64,7 +64,7 @@ func (s *Service) verifyBlkPreState(ctx context.Context, b interfaces.ReadOnlyBe
 	parentRoot := b.ParentRoot()
 	// Loosen the check to HasBlock because state summary gets saved in batches
 	// during initial syncing. There's no risk given a state summary object is just a
-	// a subset of the block object.
+	// subset of the block object.
 	if !s.cfg.BeaconDB.HasStateSummary(ctx, parentRoot) && !s.cfg.BeaconDB.HasBlock(ctx, parentRoot) {
 		return errors.New("could not reconstruct parent state")
 	}
@@ -230,7 +230,9 @@ func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) e
 	// to be included(rather than the last one to be processed). This was most likely
 	// done as the state cannot represent signed integers.
 	eth1DepositIndex -= 1
-	s.cfg.DepositCache.InsertFinalizedDeposits(ctx, int64(eth1DepositIndex))
+	if err = s.cfg.DepositCache.InsertFinalizedDeposits(ctx, int64(eth1DepositIndex)); err != nil {
+		return err
+	}
 	// Deposit proofs are only used during state transition and can be safely removed to save space.
 	if err = s.cfg.DepositCache.PruneProofs(ctx, int64(eth1DepositIndex)); err != nil {
 		return errors.Wrap(err, "could not prune deposit proofs")
--- a/beacon-chain/blockchain/process_block_test.go
+++ b/beacon-chain/blockchain/process_block_test.go
@@ -12,9 +12,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	gethtypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/pkg/errors"
-	mock "github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain/testing"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache/depositcache"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/signing"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
@@ -24,9 +22,8 @@ import (
 	mockExecution "github.com/prysmaticlabs/prysm/v4/beacon-chain/execution/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
 	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
@@ -45,18 +42,9 @@ import (
 )

 func TestStore_OnBlock(t *testing.T) {
-	ctx := context.Background()
+	service, tr := minimalTestService(t)
+	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs

-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	var genesisStateRoot [32]byte
 	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
 	util.SaveBlock(t, ctx, beaconDB, genesis)
@@ -151,17 +139,8 @@ func TestStore_OnBlock(t *testing.T) {
 }

 func TestStore_OnBlockBatch(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	st, keys := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, st))
@@ -184,7 +163,7 @@ func TestStore_OnBlockBatch(t *testing.T) {
 		blks = append(blks, wsb)
 		blkRoots = append(blkRoots, root)
 	}
-	err = service.onBlockBatch(ctx, blks, blkRoots[1:])
+	err := service.onBlockBatch(ctx, blks, blkRoots[1:])
 	require.ErrorIs(t, errWrongBlockCount, err)
 	err = service.onBlockBatch(ctx, blks, blkRoots)
 	require.NoError(t, err)
@@ -195,17 +174,9 @@ func TestStore_OnBlockBatch(t *testing.T) {
 }

 func TestStore_OnBlockBatch_NotifyNewPayload(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	st, keys := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, st))
 	bState := st.Copy()
@@ -226,22 +197,12 @@ func TestStore_OnBlockBatch_NotifyNewPayload(t *testing.T) {
 		blks = append(blks, wsb)
 		blkRoots = append(blkRoots, root)
 	}
-	err = service.onBlockBatch(ctx, blks, blkRoots)
-	require.NoError(t, err)
+	require.NoError(t, service.onBlockBatch(ctx, blks, blkRoots))
 }

 func TestCachedPreState_CanGetFromStateSummary(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

 	st, keys := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, st))
@@ -259,16 +220,8 @@ func TestCachedPreState_CanGetFromStateSummary(t *testing.T) {
 }

 func TestFillForkChoiceMissingBlocks_CanSave(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	service.cfg.ForkChoiceStore = doublylinkedtree.New()
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

 	st, _ := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, st))
@@ -308,16 +261,8 @@ func TestFillForkChoiceMissingBlocks_CanSave(t *testing.T) {
 }

 func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	service.cfg.ForkChoiceStore = doublylinkedtree.New()
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

 	st, _ := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, st))
@@ -359,16 +304,8 @@ func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
 }

 func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	service.cfg.ForkChoiceStore = doublylinkedtree.New()
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

 	var genesisStateRoot [32]byte
 	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
@@ -417,17 +354,8 @@ func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
 }

 func TestFillForkChoiceMissingBlocks_FinalizedSibling(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fc)),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	service.cfg.ForkChoiceStore = doublylinkedtree.New()
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

 	var genesisStateRoot [32]byte
 	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
@@ -565,17 +493,8 @@ func TestAncestorByDB_CtxErr(t *testing.T) {
 }

 func TestAncestor_HandleSkipSlot(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	beaconDB := tr.db

 	b1 := util.NewBeaconBlock()
 	b1.Block.Slot = 1
@@ -656,17 +575,8 @@ func TestAncestor_CanUseForkchoice(t *testing.T) {
 }

 func TestAncestor_CanUseDB(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, beaconDB := tr.ctx, tr.db

 	b1 := util.NewBeaconBlock()
 	b1.Block.Slot = 1
@@ -726,26 +636,13 @@ func TestHandleEpochBoundary_UpdateFirstSlot(t *testing.T) {
 	s, _ := util.DeterministicGenesisState(t, 1024)
 	service.head = &head{state: s}
 	require.NoError(t, s.SetSlot(2*params.BeaconConfig().SlotsPerEpoch))
-	require.NoError(t, service.handleEpochBoundary(ctx, s))
+	require.NoError(t, service.handleEpochBoundary(ctx, s, []byte{}))
 	require.Equal(t, 3*params.BeaconConfig().SlotsPerEpoch, service.nextEpochBoundarySlot)
 }

 func TestOnBlock_CanFinalize_WithOnTick(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithDepositCache(depositCache),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithAttestationPool(attestations.NewPool()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, fcs := tr.ctx, tr.fcs

 	gs, keys := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -781,21 +678,8 @@ func TestOnBlock_CanFinalize_WithOnTick(t *testing.T) {
 }

 func TestOnBlock_CanFinalize(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithDepositCache(depositCache),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithAttestationPool(attestations.NewPool()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	gs, keys := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -829,39 +713,15 @@ func TestOnBlock_CanFinalize(t *testing.T) {
 }

 func TestOnBlock_NilBlock(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithDepositCache(depositCache),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)

-	err = service.onBlock(ctx, nil, [32]byte{})
+	err := service.onBlock(tr.ctx, nil, [32]byte{})
 	require.Equal(t, true, IsInvalidBlock(err))
 }

 func TestOnBlock_InvalidSignature(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithDepositCache(depositCache),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	gs, keys := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -884,21 +744,8 @@ func TestOnBlock_CallNewPayloadAndForkchoiceUpdated(t *testing.T) {
 	config.BellatrixForkEpoch = 2
 	params.OverrideBeaconConfig(config)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithDepositCache(depositCache),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithAttestationPool(attestations.NewPool()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	gs, keys := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -917,13 +764,8 @@ func TestOnBlock_CallNewPayloadAndForkchoiceUpdated(t *testing.T) {
 }

 func TestInsertFinalizedDeposits(t *testing.T) {
-	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts = append(opts, WithDepositCache(depositCache))
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, depositCache := tr.ctx, tr.dc

 	gs, _ := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -951,13 +793,8 @@ func TestInsertFinalizedDeposits(t *testing.T) {
 }

 func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
-	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts = append(opts, WithDepositCache(depositCache))
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx, depositCache := tr.ctx, tr.dc

 	gs, _ := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -980,7 +817,7 @@ func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
 		}, Proof: [][]byte{root}}, 100+i, int64(i), bytesutil.ToBytes32(root)))
 	}
 	// Insert 3 deposits before hand.
-	depositCache.InsertFinalizedDeposits(ctx, 2)
+	require.NoError(t, depositCache.InsertFinalizedDeposits(ctx, 2))

 	assert.NoError(t, service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k'}))
 	fDeposits := depositCache.FinalizedDeposits(ctx)
@@ -1084,18 +921,8 @@ func Test_validateMergeTransitionBlock(t *testing.T) {
 	cfg.TerminalBlockHash = params.BeaconConfig().ZeroHash
 	params.OverrideBeaconConfig(cfg)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-		WithAttestationPool(attestations.NewPool()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t, WithProposerIdsCache(cache.NewProposerPayloadIDsCache()))
+	ctx := tr.ctx

 	aHash := common.BytesToHash([]byte("a"))
 	bHash := common.BytesToHash([]byte("b"))
@@ -1222,17 +1049,8 @@ func Test_validateMergeTransitionBlock(t *testing.T) {
 }

 func TestService_insertSlashingsToForkChoiceStore(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	beaconState, privKeys := util.DeterministicGenesisState(t, 100)
 	att1 := util.HydrateIndexedAttestation(&ethpb.IndexedAttestation{
@@ -1273,21 +1091,8 @@ func TestService_insertSlashingsToForkChoiceStore(t *testing.T) {
 }

 func TestOnBlock_ProcessBlocksParallel(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	depositCache, err := depositcache.New()
-	require.NoError(t, err)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-		WithDepositCache(depositCache),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithAttestationPool(attestations.NewPool()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	gs, keys := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
@@ -1352,17 +1157,8 @@ func TestOnBlock_ProcessBlocksParallel(t *testing.T) {
 }

 func Test_verifyBlkFinalizedSlot_invalidBlock(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	service, _ := minimalTestService(t)

-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	require.NoError(t, service.cfg.ForkChoiceStore.UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: 1}))
 	blk := util.HydrateBeaconBlock(&ethpb.BeaconBlock{Slot: 1})
 	wb, err := consensusblocks.NewBeaconBlock(blk)
@@ -1385,22 +1181,9 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 	config.BellatrixForkEpoch = 2
 	params.OverrideBeaconConfig(config)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
 	mockEngine := &mockExecution.EngineClient{ErrNewPayload: execution.ErrAcceptedSyncingPayloadStatus, ErrForkchoiceUpdated: execution.ErrAcceptedSyncingPayloadStatus}
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithAttestationPool(attestations.NewPool()),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithExecutionEngineCaller(mockEngine),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t, WithExecutionEngineCaller(mockEngine))
+	ctx := tr.ctx

 	st, keys := util.DeterministicGenesisState(t, 64)
 	stateRoot, err := st.HashTreeRoot(ctx)
@@ -1545,22 +1328,9 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 	config.BellatrixForkEpoch = 2
 	params.OverrideBeaconConfig(config)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
 	mockEngine := &mockExecution.EngineClient{ErrNewPayload: execution.ErrAcceptedSyncingPayloadStatus, ErrForkchoiceUpdated: execution.ErrAcceptedSyncingPayloadStatus}
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithAttestationPool(attestations.NewPool()),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithExecutionEngineCaller(mockEngine),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t, WithExecutionEngineCaller(mockEngine))
+	ctx := tr.ctx

 	st, keys := util.DeterministicGenesisState(t, 64)
 	stateRoot, err := st.HashTreeRoot(ctx)
@@ -1706,22 +1476,9 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	config.BellatrixForkEpoch = 2
 	params.OverrideBeaconConfig(config)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
 	mockEngine := &mockExecution.EngineClient{ErrNewPayload: execution.ErrAcceptedSyncingPayloadStatus, ErrForkchoiceUpdated: execution.ErrAcceptedSyncingPayloadStatus}
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithAttestationPool(attestations.NewPool()),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithExecutionEngineCaller(mockEngine),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t, WithExecutionEngineCaller(mockEngine))
+	ctx := tr.ctx

 	st, keys := util.DeterministicGenesisState(t, 64)
 	stateRoot, err := st.HashTreeRoot(ctx)
@@ -1914,27 +1671,9 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	config.BellatrixForkEpoch = 2
 	params.OverrideBeaconConfig(config)

-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
 	mockEngine := &mockExecution.EngineClient{ErrNewPayload: execution.ErrAcceptedSyncingPayloadStatus, ErrForkchoiceUpdated: execution.ErrAcceptedSyncingPayloadStatus}
-	attSrv, err := attestations.NewService(ctx, &attestations.Config{})
-	require.NoError(t, err)
-	newfc := doublylinkedtree.New()
-	newStateGen := stategen.New(beaconDB, newfc)
-	newfc.SetBalancesByRooter(newStateGen.ActiveNonSlashedBalancesByRoot)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithAttestationPool(attestations.NewPool()),
-		WithStateGen(newStateGen),
-		WithForkChoiceStore(newfc),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithExecutionEngineCaller(mockEngine),
-		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
-		WithAttestationService(attSrv),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t, WithExecutionEngineCaller(mockEngine))
+	ctx := tr.ctx

 	genesisState, keys := util.DeterministicGenesisState(t, 64)
 	stateRoot, err := genesisState.HashTreeRoot(ctx)
@@ -2083,18 +1822,8 @@ func TestNoViableHead_Reboot(t *testing.T) {
 }

 func TestOnBlock_HandleBlockAttestations(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithAttestationPool(attestations.NewPool()),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	st, keys := util.DeterministicGenesisState(t, 64)
 	stateRoot, err := st.HashTreeRoot(ctx)
@@ -2146,30 +1875,34 @@ func TestOnBlock_HandleBlockAttestations(t *testing.T) {
 	r3 := bytesutil.ToBytes32(a3.Data.BeaconBlockRoot)
 	require.Equal(t, false, service.cfg.ForkChoiceStore.HasNode(r3))

-	require.NoError(t, service.handleBlockAttestations(ctx, wsb.Block(), st)) // fine to use the same committe as st
+	require.NoError(t, service.handleBlockAttestations(ctx, wsb.Block(), st)) // fine to use the same committee as st
 	require.Equal(t, 0, service.cfg.AttPool.ForkchoiceAttestationCount())
-	require.NoError(t, service.handleBlockAttestations(ctx, wsb3.Block(), st3)) // fine to use the same committe as st
+	require.NoError(t, service.handleBlockAttestations(ctx, wsb3.Block(), st3)) // fine to use the same committee as st
 	require.Equal(t, 1, len(service.cfg.AttPool.BlockAttestations()))
 }

 func TestFillMissingBlockPayloadId_DiffSlotExitEarly(t *testing.T) {
-	fc := doublylinkedtree.New()
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
+	logHook := logTest.NewGlobal()
+	service, tr := minimalTestService(t)
+	service.lateBlockTasks(tr.ctx)
+	require.LogsDoNotContain(t, logHook, "could not perform late block tasks")
+}

-	opts := []Option{
-		WithForkChoiceStore(fc),
-		WithStateGen(stategen.New(beaconDB, fc)),
-	}
+func TestFillMissingBlockPayloadId_PrepareAllPayloads(t *testing.T) {
+	logHook := logTest.NewGlobal()
+	resetCfg := features.InitWithReset(&features.Flags{
+		PrepareAllPayloads: true,
+	})
+	defer resetCfg()

-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	require.NoError(t, service.fillMissingBlockPayloadId(ctx), 0)
+	service, tr := minimalTestService(t)
+	service.lateBlockTasks(tr.ctx)
+	require.LogsDoNotContain(t, logHook, "could not perform late block tasks")
 }

 // Helper function to simulate the block being on time or delayed for proposer
 // boost. It alters the genesisTime tracked by the store.
-func driftGenesisTime(s *Service, slot int64, delay int64) {
+func driftGenesisTime(s *Service, slot, delay int64) {
 	offset := slot*int64(params.BeaconConfig().SecondsPerSlot) - delay
 	s.SetGenesisTime(time.Unix(time.Now().Unix()-offset, 0))
 }
--- a/beacon-chain/blockchain/receive_attestation.go
+++ b/beacon-chain/blockchain/receive_attestation.go
@@ -7,8 +7,6 @@ import (
 	"time"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v4/async/event"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/config/features"
@@ -28,7 +26,7 @@ const reorgLateBlockCountAttestations = 2 * time.Second
 // 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)
+	AttestationTargetState(ctx context.Context, target *ethpb.Checkpoint) (state.ReadOnlyBeaconState, error)
 }

 // AttestationReceiver interface defines the methods of chain service receive and processing new attestations.
@@ -39,7 +37,7 @@ type AttestationReceiver interface {
 }

 // AttestationTargetState returns the pre state of attestation.
-func (s *Service) AttestationTargetState(ctx context.Context, target *ethpb.Checkpoint) (state.BeaconState, error) {
+func (s *Service) AttestationTargetState(ctx context.Context, target *ethpb.Checkpoint) (state.ReadOnlyBeaconState, error) {
 	ss, err := slots.EpochStart(target.Epoch)
 	if err != nil {
 		return nil, err
@@ -47,6 +45,9 @@ func (s *Service) AttestationTargetState(ctx context.Context, target *ethpb.Chec
 	if err := slots.ValidateClock(ss, uint64(s.genesisTime.Unix())); err != nil {
 		return nil, err
 	}
+	// We acquire the lock here instead than on gettAttPreState because that function gets called from UpdateHead that holds a write lock
+	s.cfg.ForkChoiceStore.RLock()
+	defer s.cfg.ForkChoiceStore.RUnlock()
 	return s.getAttPreState(ctx, target)
 }

@@ -67,20 +68,13 @@ func (s *Service) VerifyLmdFfgConsistency(ctx context.Context, a *ethpb.Attestat
 }

 // This routine processes fork choice attestations from the pool to account for validator votes and fork choice.
-func (s *Service) spawnProcessAttestationsRoutine(stateFeed *event.Feed) {
-	// Wait for state to be initialized.
-	stateChannel := make(chan *feed.Event, 1)
-	stateSub := stateFeed.Subscribe(stateChannel)
+func (s *Service) spawnProcessAttestationsRoutine() {
 	go func() {
-		select {
-		case <-s.ctx.Done():
-			stateSub.Unsubscribe()
+		_, err := s.clockWaiter.WaitForClock(s.ctx)
+		if err != nil {
+			log.WithError(err).Error("spawnProcessAttestationsRoutine failed to receive genesis data")
 			return
-		case <-stateChannel:
-			stateSub.Unsubscribe()
-			break
 		}
-
 		if s.genesisTime.IsZero() {
 			log.Warn("ProcessAttestations routine waiting for genesis time")
 			for s.genesisTime.IsZero() {
@@ -100,8 +94,10 @@ func (s *Service) spawnProcessAttestationsRoutine(stateFeed *event.Feed) {
 			case <-s.ctx.Done():
 				return
 			case <-pat.C():
+				log.Infof("proposer_mocker: calling updated head via offset ticker")
 				s.UpdateHead(s.ctx, s.CurrentSlot()+1)
 			case <-st.C():
+				log.Infof("proposer_mocker: calling updated head via normal slot ticker in spawn atts")
 				s.cfg.ForkChoiceStore.Lock()
 				if err := s.cfg.ForkChoiceStore.NewSlot(s.ctx, s.CurrentSlot()); err != nil {
 					log.WithError(err).Error("could not process new slot")
@@ -117,6 +113,9 @@ func (s *Service) spawnProcessAttestationsRoutine(stateFeed *event.Feed) {
 // UpdateHead updates the canonical head of the chain based on information from fork-choice attestations and votes.
 // The caller of this function MUST hold a lock in forkchoice
 func (s *Service) UpdateHead(ctx context.Context, proposingSlot primitives.Slot) {
+	ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.UpdateHead")
+	defer span.End()
+
 	start := time.Now()
 	s.cfg.ForkChoiceStore.Lock()
 	defer s.cfg.ForkChoiceStore.Unlock()
@@ -127,6 +126,8 @@ func (s *Service) UpdateHead(ctx context.Context, proposingSlot primitives.Slot)
 	}
 	s.processAttestations(ctx, disparity)

+	log.Infof("proposer_mocker: process attestations in fc took %s", time.Since(start).String())
+
 	processAttsElapsedTime.Observe(float64(time.Since(start).Milliseconds()))

 	start = time.Now()
@@ -139,17 +140,21 @@ func (s *Service) UpdateHead(ctx context.Context, proposingSlot primitives.Slot)
 		s.headLock.RUnlock()
 	}
 	newAttHeadElapsedTime.Observe(float64(time.Since(start).Milliseconds()))
+	log.Infof("proposer_mocker: head root in fc took %s", time.Since(start).String())

-	s.headLock.RLock()
-	if s.headRoot() != newHeadRoot {
+	changed, err := s.forkchoiceUpdateWithExecution(s.ctx, newHeadRoot, proposingSlot)
+	if err != nil {
+		log.WithError(err).Error("could not update forkchoice")
+	}
+	log.Infof("proposer_mocker: fcu call in fc took %s", time.Since(start).String())
+
+	if changed {
+		s.headLock.RLock()
 		log.WithFields(logrus.Fields{
 			"oldHeadRoot": fmt.Sprintf("%#x", s.headRoot()),
 			"newHeadRoot": fmt.Sprintf("%#x", newHeadRoot),
 		}).Debug("Head changed due to attestations")
-	}
-	s.headLock.RUnlock()
-	if err := s.forkchoiceUpdateWithExecution(s.ctx, newHeadRoot, proposingSlot); err != nil {
-		log.WithError(err).Error("could not update forkchoice")
+		s.headLock.RUnlock()
 	}
 }

--- a/beacon-chain/blockchain/receive_attestation_test.go
+++ b/beacon-chain/blockchain/receive_attestation_test.go
@@ -7,11 +7,7 @@ import (

 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
-	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/attestations"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
@@ -31,22 +27,18 @@ var (

 func TestAttestationCheckPtState_FarFutureSlot(t *testing.T) {
 	helpers.ClearCache()
-	beaconDB := testDB.SetupDB(t)
+	service, _ := minimalTestService(t)

-	chainService := setupBeaconChain(t, beaconDB)
-	chainService.genesisTime = time.Now()
+	service.genesisTime = time.Now()

 	e := primitives.Epoch(slots.MaxSlotBuffer/uint64(params.BeaconConfig().SlotsPerEpoch) + 1)
-	_, err := chainService.AttestationTargetState(context.Background(), &ethpb.Checkpoint{Epoch: e})
+	_, err := service.AttestationTargetState(context.Background(), &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)
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	b32 := util.NewBeaconBlock()
 	b32.Block.Slot = 32
@@ -69,11 +61,8 @@ func TestVerifyLMDFFGConsistent_NotOK(t *testing.T) {
 }

 func TestVerifyLMDFFGConsistent_OK(t *testing.T) {
-	ctx := context.Background()
-
-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	ctx := tr.ctx

 	b32 := util.NewBeaconBlock()
 	b32.Block.Slot = 32
@@ -96,13 +85,10 @@ func TestVerifyLMDFFGConsistent_OK(t *testing.T) {
 }

 func TestProcessAttestations_Ok(t *testing.T) {
+	service, tr := minimalTestService(t)
 	hook := logTest.NewGlobal()
-	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
-	opts = append(opts, WithAttestationPool(attestations.NewPool()))
+	ctx := tr.ctx

-	service, err := NewService(ctx, opts...)
-	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))
@@ -126,21 +112,9 @@ func TestProcessAttestations_Ok(t *testing.T) {
 }

 func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	newStateGen := stategen.New(beaconDB, fcs)
-	fcs.SetBalancesByRooter(newStateGen.ActiveNonSlashedBalancesByRoot)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(newStateGen),
-		WithAttestationPool(attestations.NewPool()),
-		WithStateNotifier(&mockBeaconNode{}),
-		WithForkChoiceStore(fcs),
-	}
+	service, tr := minimalTestService(t)
+	ctx, fcs := tr.ctx, tr.fcs

-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	service.genesisTime = prysmTime.Now().Add(-2 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)
 	genesisState, pks := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, genesisState))
@@ -189,21 +163,9 @@ func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
 }

 func TestService_UpdateHead_NoAtts(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fcs := doublylinkedtree.New()
-	newStateGen := stategen.New(beaconDB, fcs)
-	fcs.SetBalancesByRooter(newStateGen.ActiveNonSlashedBalancesByRoot)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithAttestationPool(attestations.NewPool()),
-		WithStateNotifier(&mockBeaconNode{}),
-		WithStateGen(newStateGen),
-		WithForkChoiceStore(fcs),
-	}
+	service, tr := minimalTestService(t)
+	ctx, fcs := tr.ctx, tr.fcs

-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	service.genesisTime = prysmTime.Now().Add(-2 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)
 	genesisState, pks := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, genesisState))
--- a/beacon-chain/blockchain/receive_block.go
+++ b/beacon-chain/blockchain/receive_block.go
@@ -179,10 +179,14 @@ func (s *Service) prunePostBlockOperationPools(ctx context.Context, blk interfac
 		return errors.Wrap(err, "could not process BLSToExecutionChanges")
 	}

-	//  Mark attester slashings as seen so we don't include same ones in future blocks.
+	// Mark slashings as seen so we don't include same ones in future blocks.
 	for _, as := range blk.Block().Body().AttesterSlashings() {
 		s.cfg.SlashingPool.MarkIncludedAttesterSlashing(as)
 	}
+	for _, ps := range blk.Block().Body().ProposerSlashings() {
+		s.cfg.SlashingPool.MarkIncludedProposerSlashing(ps)
+	}
+
 	return nil
 }

--- a/beacon-chain/blockchain/receive_block_test.go
+++ b/beacon-chain/blockchain/receive_block_test.go
@@ -7,12 +7,7 @@ import (
 	"time"

 	blockchainTesting "github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain/testing"
-	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/attestations"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/blstoexec"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/voluntaryexits"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
@@ -125,22 +120,15 @@ func TestService_ReceiveBlock(t *testing.T) {
 	for _, tt := range tests {
 		wg.Add(1)
 		t.Run(tt.name, func(t *testing.T) {
-			beaconDB := testDB.SetupDB(t)
+			s, tr := minimalTestService(t,
+				WithFinalizedStateAtStartUp(genesis),
+				WithExitPool(voluntaryexits.NewPool()),
+				WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}))
+
+			beaconDB := tr.db
 			genesisBlockRoot := bytesutil.ToBytes32(nil)
 			require.NoError(t, beaconDB.SaveState(ctx, genesis, genesisBlockRoot))

-			fc := doublylinkedtree.New()
-			opts := []Option{
-				WithDatabase(beaconDB),
-				WithForkChoiceStore(fc),
-				WithAttestationPool(attestations.NewPool()),
-				WithExitPool(voluntaryexits.NewPool()),
-				WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}),
-				WithStateGen(stategen.New(beaconDB, fc)),
-				WithFinalizedStateAtStartUp(genesis),
-			}
-			s, err := NewService(ctx, opts...)
-			require.NoError(t, err)
 			// Initialize it here.
 			_ = s.cfg.StateNotifier.StateFeed()
 			require.NoError(t, s.saveGenesisData(ctx, genesis))
@@ -162,25 +150,16 @@ func TestService_ReceiveBlock(t *testing.T) {
 }

 func TestService_ReceiveBlockUpdateHead(t *testing.T) {
-	ctx := context.Background()
+	s, tr := minimalTestService(t,
+		WithExitPool(voluntaryexits.NewPool()),
+		WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}))
+	ctx, beaconDB := tr.ctx, tr.db
 	genesis, keys := util.DeterministicGenesisState(t, 64)
 	b, err := util.GenerateFullBlock(genesis, keys, util.DefaultBlockGenConfig(), 1)
 	assert.NoError(t, err)
-	beaconDB := testDB.SetupDB(t)
 	genesisBlockRoot := bytesutil.ToBytes32(nil)
 	require.NoError(t, beaconDB.SaveState(ctx, genesis, genesisBlockRoot))
-	fc := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithForkChoiceStore(fc),
-		WithAttestationPool(attestations.NewPool()),
-		WithExitPool(voluntaryexits.NewPool()),
-		WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}),
-		WithStateGen(stategen.New(beaconDB, fc)),
-	}

-	s, err := NewService(ctx, opts...)
-	require.NoError(t, err)
 	// Initialize it here.
 	_ = s.cfg.StateNotifier.StateFeed()
 	require.NoError(t, s.saveGenesisData(ctx, genesis))
@@ -246,17 +225,8 @@ func TestService_ReceiveBlockBatch(t *testing.T) {

 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			fc := doublylinkedtree.New()
-			beaconDB := testDB.SetupDB(t)
-			opts := []Option{
-				WithDatabase(beaconDB),
-				WithForkChoiceStore(fc),
-				WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}),
-				WithStateGen(stategen.New(beaconDB, fc)),
-			}
-			s, err := NewService(ctx, opts...)
-			require.NoError(t, err)
-			err = s.saveGenesisData(ctx, genesis)
+			s, _ := minimalTestService(t, WithStateNotifier(&blockchainTesting.MockStateNotifier{RecordEvents: true}))
+			err := s.saveGenesisData(ctx, genesis)
 			require.NoError(t, err)
 			root, err := tt.args.block.Block.HashTreeRoot()
 			require.NoError(t, err)
@@ -276,10 +246,7 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 }

 func TestService_HasBlock(t *testing.T) {
-	opts := testServiceOptsWithDB(t)
-	opts = append(opts, WithStateNotifier(&blockchainTesting.MockStateNotifier{}))
-	s, err := NewService(context.Background(), opts...)
-	require.NoError(t, err)
+	s, _ := minimalTestService(t)
 	r := [32]byte{'a'}
 	if s.HasBlock(context.Background(), r) {
 		t.Error("Should not have block")
@@ -299,10 +266,8 @@ func TestService_HasBlock(t *testing.T) {
 }

 func TestCheckSaveHotStateDB_Enabling(t *testing.T) {
-	opts := testServiceOptsWithDB(t)
 	hook := logTest.NewGlobal()
-	s, err := NewService(context.Background(), opts...)
-	require.NoError(t, err)
+	s, _ := minimalTestService(t)
 	st := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epochsSinceFinalitySaveHotStateDB))
 	s.genesisTime = time.Now().Add(time.Duration(-1*int64(st)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)

@@ -312,9 +277,9 @@ func TestCheckSaveHotStateDB_Enabling(t *testing.T) {

 func TestCheckSaveHotStateDB_Disabling(t *testing.T) {
 	hook := logTest.NewGlobal()
-	opts := testServiceOptsWithDB(t)
-	s, err := NewService(context.Background(), opts...)
-	require.NoError(t, err)
+
+	s, _ := minimalTestService(t)
+
 	st := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epochsSinceFinalitySaveHotStateDB))
 	s.genesisTime = time.Now().Add(time.Duration(-1*int64(st)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)
 	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
@@ -326,9 +291,7 @@ func TestCheckSaveHotStateDB_Disabling(t *testing.T) {

 func TestCheckSaveHotStateDB_Overflow(t *testing.T) {
 	hook := logTest.NewGlobal()
-	opts := testServiceOptsWithDB(t)
-	s, err := NewService(context.Background(), opts...)
-	require.NoError(t, err)
+	s, _ := minimalTestService(t)
 	s.genesisTime = time.Now()

 	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
@@ -336,19 +299,8 @@ func TestCheckSaveHotStateDB_Overflow(t *testing.T) {
 }

 func TestHandleBlockBLSToExecutionChanges(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	fc := doublylinkedtree.New()
-	pool := blstoexec.NewPool()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fc)),
-		WithForkChoiceStore(fc),
-		WithStateNotifier(&blockchainTesting.MockStateNotifier{}),
-		WithBLSToExecPool(pool),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
+	service, tr := minimalTestService(t)
+	pool := tr.blsPool

 	t.Run("pre Capella block", func(t *testing.T) {
 		body := &ethpb.BeaconBlockBodyBellatrix{}
--- a/beacon-chain/blockchain/service.go
+++ b/beacon-chain/blockchain/service.go
@@ -17,6 +17,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
+	coreTime "github.com/prysmaticlabs/prysm/v4/beacon-chain/core/time"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/execution"
@@ -27,6 +28,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/slashings"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/p2p"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/startup"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v4/config/features"
@@ -57,6 +59,9 @@ type Service struct {
 	initSyncBlocks        map[[32]byte]interfaces.ReadOnlySignedBeaconBlock
 	initSyncBlocksLock    sync.RWMutex
 	wsVerifier            *WeakSubjectivityVerifier
+	clockSetter           startup.ClockSetter
+	clockWaiter           startup.ClockWaiter
+	syncComplete          chan struct{}
 }

 // config options for the service.
@@ -83,6 +88,8 @@ type config struct {
 	ExecutionEngineCaller   execution.EngineCaller
 }

+var ErrMissingClockSetter = errors.New("blockchain Service initialized without a startup.ClockSetter")
+
 // 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) {
@@ -100,6 +107,9 @@ func NewService(ctx context.Context, opts ...Option) (*Service, error) {
 			return nil, err
 		}
 	}
+	if srv.clockSetter == nil {
+		return nil, ErrMissingClockSetter
+	}
 	var err error
 	srv.wsVerifier, err = NewWeakSubjectivityVerifier(srv.cfg.WeakSubjectivityCheckpt, srv.cfg.BeaconDB)
 	if err != nil {
@@ -121,8 +131,8 @@ func (s *Service) Start() {
 			log.Fatal(err)
 		}
 	}
-	s.spawnProcessAttestationsRoutine(s.cfg.StateNotifier.StateFeed())
-	s.fillMissingPayloadIDRoutine(s.ctx, s.cfg.StateNotifier.StateFeed())
+	s.spawnProcessAttestationsRoutine()
+	go s.runLateBlockTasks()
 }

 // Stop the blockchain service's main event loop and associated goroutines.
@@ -236,13 +246,10 @@ func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 		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(),
-		},
-	})
+	vr := bytesutil.ToBytes32(saved.GenesisValidatorsRoot())
+	if err := s.clockSetter.SetClock(startup.NewClock(s.genesisTime, vr)); err != nil {
+		return errors.Wrap(err, "failed to initialize blockchain service")
+	}

 	return nil
 }
@@ -302,7 +309,13 @@ func (s *Service) initializeHeadFromDB(ctx context.Context) error {
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized block")
 	}
-	if err := s.setHead(finalizedRoot, finalizedBlock, finalizedState); err != nil {
+	if err := s.setHead(&head{
+		finalizedRoot,
+		finalizedBlock,
+		finalizedState,
+		finalizedBlock.Block().Slot(),
+		false,
+	}); err != nil {
 		return errors.Wrap(err, "could not set head")
 	}

@@ -359,15 +372,10 @@ func (s *Service) onExecutionChainStart(ctx context.Context, genesisTime time.Ti
 	}
 	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(),
-		},
-	})
+	vr := bytesutil.ToBytes32(initializedState.GenesisValidatorsRoot())
+	if err := s.clockSetter.SetClock(startup.NewClock(genesisTime, vr)); err != nil {
+		log.WithError(err).Fatal("failed to initialize blockchain service from execution start event")
+	}
 }

 // initializes the state and genesis block of the beacon chain to persistent storage
@@ -401,7 +409,7 @@ func (s *Service) initializeBeaconChain(
 	if err := helpers.UpdateCommitteeCache(ctx, genesisState, 0); err != nil {
 		return nil, err
 	}
-	if err := helpers.UpdateProposerIndicesInCache(ctx, genesisState); err != nil {
+	if err := helpers.UpdateProposerIndicesInCache(ctx, genesisState, coreTime.CurrentEpoch(genesisState)); err != nil {
 		return nil, err
 	}

@@ -439,7 +447,13 @@ func (s *Service) saveGenesisData(ctx context.Context, genesisState state.Beacon
 	}
 	s.cfg.ForkChoiceStore.SetGenesisTime(uint64(s.genesisTime.Unix()))

-	if err := s.setHead(genesisBlkRoot, genesisBlk, genesisState); err != nil {
+	if err := s.setHead(&head{
+		genesisBlkRoot,
+		genesisBlk,
+		genesisState,
+		genesisBlk.Block().Slot(),
+		false,
+	}); err != nil {
 		log.WithError(err).Fatal("Could not set head")
 	}
 	return nil
--- a/beacon-chain/blockchain/service_test.go
+++ b/beacon-chain/blockchain/service_test.go
@@ -8,13 +8,9 @@ import (
 	"time"

 	"github.com/ethereum/go-ethereum/common"
-	"github.com/prysmaticlabs/prysm/v4/async/event"
-	mock "github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain/testing"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache/depositcache"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed"
-	statefeed "github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db"
@@ -23,7 +19,9 @@ import (
 	mockExecution "github.com/prysmaticlabs/prysm/v4/beacon-chain/execution/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/attestations"
-	"github.com/prysmaticlabs/prysm/v4/beacon-chain/p2p"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/slashings"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/voluntaryexits"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/startup"
 	state_native "github.com/prysmaticlabs/prysm/v4/beacon-chain/state/state-native"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v4/config/features"
@@ -38,45 +36,8 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/testing/util"
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 	logTest "github.com/sirupsen/logrus/hooks/test"
-	"google.golang.org/protobuf/proto"
 )

-type mockBeaconNode struct {
-	stateFeed *event.Feed
-}
-
-// StateFeed mocks the same method in the beacon node.
-func (mbn *mockBeaconNode) StateFeed() *event.Feed {
-	if mbn.stateFeed == nil {
-		mbn.stateFeed = new(event.Feed)
-	}
-	return mbn.stateFeed
-}
-
-type mockBroadcaster struct {
-	broadcastCalled bool
-}
-
-func (mb *mockBroadcaster) Broadcast(_ context.Context, _ proto.Message) error {
-	mb.broadcastCalled = true
-	return nil
-}
-
-func (mb *mockBroadcaster) BroadcastAttestation(_ context.Context, _ uint64, _ *ethpb.Attestation) error {
-	mb.broadcastCalled = true
-	return nil
-}
-
-func (mb *mockBroadcaster) BroadcastSyncCommitteeMessage(_ context.Context, _ uint64, _ *ethpb.SyncCommitteeMessage) error {
-	mb.broadcastCalled = true
-	return nil
-}
-
-func (mb *mockBroadcaster) BroadcastBLSChanges(_ context.Context, _ []*ethpb.SignedBLSToExecutionChange) {
-}
-
-var _ p2p.Broadcaster = (*mockBroadcaster)(nil)
-
 func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 	ctx := context.Background()
 	var web3Service *execution.Service
@@ -131,12 +92,15 @@ func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 		WithDepositCache(depositCache),
 		WithChainStartFetcher(web3Service),
 		WithAttestationPool(attestations.NewPool()),
+		WithSlashingPool(slashings.NewPool()),
+		WithExitPool(voluntaryexits.NewPool()),
 		WithP2PBroadcaster(&mockBroadcaster{}),
 		WithStateNotifier(&mockBeaconNode{}),
 		WithForkChoiceStore(fc),
 		WithAttestationService(attService),
 		WithStateGen(stateGen),
 		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
+		WithClockSynchronizer(startup.NewClockSynchronizer()),
 	}

 	chainService, err := NewService(ctx, opts...)
@@ -153,12 +117,14 @@ func TestChainStartStop_Initialized(t *testing.T) {

 	chainService := setupBeaconChain(t, beaconDB)

+	gt := time.Unix(23, 0)
 	genesisBlk := util.NewBeaconBlock()
 	blkRoot, err := genesisBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
 	util.SaveBlock(t, ctx, beaconDB, genesisBlk)
 	s, err := util.NewBeaconState()
 	require.NoError(t, err)
+	require.NoError(t, s.SetGenesisTime(uint64(gt.Unix())))
 	require.NoError(t, s.SetSlot(1))
 	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
 	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, blkRoot))
@@ -188,12 +154,14 @@ func TestChainStartStop_GenesisZeroHashes(t *testing.T) {

 	chainService := setupBeaconChain(t, beaconDB)

+	gt := time.Unix(23, 0)
 	genesisBlk := util.NewBeaconBlock()
 	blkRoot, err := genesisBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
 	wsb := util.SaveBlock(t, ctx, beaconDB, genesisBlk)
 	s, err := util.NewBeaconState()
 	require.NoError(t, err)
+	require.NoError(t, s.SetGenesisTime(uint64(gt.Unix())))
 	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
 	require.NoError(t, beaconDB.SaveBlock(ctx, wsb))
@@ -260,12 +228,14 @@ func TestChainService_CorrectGenesisRoots(t *testing.T) {

 	chainService := setupBeaconChain(t, beaconDB)

+	gt := time.Unix(23, 0)
 	genesisBlk := util.NewBeaconBlock()
 	blkRoot, err := genesisBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
 	util.SaveBlock(t, ctx, beaconDB, genesisBlk)
 	s, err := util.NewBeaconState()
 	require.NoError(t, err)
+	require.NoError(t, s.SetGenesisTime(uint64(gt.Unix())))
 	require.NoError(t, s.SetSlot(0))
 	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
 	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, blkRoot))
@@ -286,14 +256,9 @@ func TestChainService_CorrectGenesisRoots(t *testing.T) {
 }

 func TestChainService_InitializeChainInfo(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	ctx := context.Background()
-
 	genesis := util.NewBeaconBlock()
 	genesisRoot, err := genesis.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
-	util.SaveBlock(t, ctx, beaconDB, genesis)

 	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
 	headBlock := util.NewBeaconBlock()
@@ -305,23 +270,18 @@ func TestChainService_InitializeChainInfo(t *testing.T) {
 	require.NoError(t, headState.SetGenesisValidatorsRoot(params.BeaconConfig().ZeroHash[:]))
 	headRoot, err := headBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
+
+	c, tr := minimalTestService(t, WithFinalizedStateAtStartUp(headState))
+	ctx, beaconDB, stateGen := tr.ctx, tr.db, tr.sg
+
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
+	util.SaveBlock(t, ctx, beaconDB, genesis)
 	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
 	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
 	util.SaveBlock(t, ctx, beaconDB, headBlock)
 	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)
-	fc := doublylinkedtree.New()
-	stateGen := stategen.New(beaconDB, fc)
-	c, err := NewService(ctx,
-		WithForkChoiceStore(fc),
-		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))
 	headBlk, err := c.HeadBlock(ctx)
 	require.NoError(t, err)
@@ -341,14 +301,9 @@ func TestChainService_InitializeChainInfo(t *testing.T) {
 }

 func TestChainService_InitializeChainInfo_SetHeadAtGenesis(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	ctx := context.Background()
-
 	genesis := util.NewBeaconBlock()
 	genesisRoot, err := genesis.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
-	util.SaveBlock(t, ctx, beaconDB, genesis)

 	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
 	headBlock := util.NewBeaconBlock()
@@ -360,27 +315,21 @@ func TestChainService_InitializeChainInfo_SetHeadAtGenesis(t *testing.T) {
 	require.NoError(t, headState.SetGenesisValidatorsRoot(params.BeaconConfig().ZeroHash[:]))
 	headRoot, err := headBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
+
+	c, tr := minimalTestService(t, WithFinalizedStateAtStartUp(headState))
+	ctx, beaconDB := tr.ctx, tr.db
+
+	util.SaveBlock(t, ctx, beaconDB, genesis)
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
 	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
 	util.SaveBlock(t, ctx, beaconDB, headBlock)
-	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)}))
-	fc := doublylinkedtree.New()
-	stateGen := stategen.New(beaconDB, fc)
-	c, err := NewService(ctx,
-		WithForkChoiceStore(fc),
-		WithDatabase(beaconDB),
-		WithStateGen(stateGen),
-		WithAttestationService(attSrv),
-		WithStateNotifier(&mock.MockStateNotifier{}),
-		WithFinalizedStateAtStartUp(headState))
-	require.NoError(t, err)

 	require.NoError(t, c.StartFromSavedState(headState))
 	s, err := c.HeadState(ctx)
@@ -428,9 +377,7 @@ func TestHasBlock_ForkChoiceAndDB_DoublyLinkedTree(t *testing.T) {
 	require.NoError(t, err)
 	beaconState, err := util.NewBeaconState()
 	require.NoError(t, err)
-	wsb, err := consensusblocks.NewSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, s.insertBlockToForkchoiceStore(ctx, wsb.Block(), r, beaconState))
+	require.NoError(t, s.cfg.ForkChoiceStore.InsertNode(ctx, beaconState, r))

 	assert.Equal(t, false, s.hasBlock(ctx, [32]byte{}), "Should not have block")
 	assert.Equal(t, true, s.hasBlock(ctx, r), "Should have block")
@@ -456,17 +403,21 @@ func TestServiceStop_SaveCachedBlocks(t *testing.T) {
 }

 func TestProcessChainStartTime_ReceivedFeed(t *testing.T) {
+	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 	service := setupBeaconChain(t, beaconDB)
-	stateChannel := make(chan *feed.Event, 1)
-	stateSub := service.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
-	defer stateSub.Unsubscribe()
-	service.onExecutionChainStart(context.Background(), time.Now())
-
-	stateEvent := <-stateChannel
-	require.Equal(t, int(stateEvent.Type), statefeed.Initialized)
-	_, ok := stateEvent.Data.(*statefeed.InitializedData)
-	require.Equal(t, true, ok)
+	mgs := &MockClockSetter{}
+	service.clockSetter = mgs
+	gt := time.Now()
+	service.onExecutionChainStart(context.Background(), gt)
+	gs, err := beaconDB.GenesisState(ctx)
+	require.NoError(t, err)
+	require.NotEqual(t, nil, gs)
+	require.Equal(t, 32, len(gs.GenesisValidatorsRoot()))
+	var zero [32]byte
+	require.DeepNotEqual(t, gs.GenesisValidatorsRoot(), zero[:])
+	require.Equal(t, gt, mgs.G.GenesisTime())
+	require.Equal(t, bytesutil.ToBytes32(gs.GenesisValidatorsRoot()), mgs.G.GenesisValidatorsRoot())
 }

 func BenchmarkHasBlockDB(b *testing.B) {
@@ -500,9 +451,7 @@ func BenchmarkHasBlockForkChoiceStore_DoublyLinkedTree(b *testing.B) {
 	bs := &ethpb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}}
 	beaconState, err := state_native.InitializeFromProtoPhase0(bs)
 	require.NoError(b, err)
-	wsb, err := consensusblocks.NewSignedBeaconBlock(blk)
-	require.NoError(b, err)
-	require.NoError(b, s.insertBlockToForkchoiceStore(ctx, wsb.Block(), r, beaconState))
+	require.NoError(b, s.cfg.ForkChoiceStore.InsertNode(ctx, beaconState, r))

 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
@@ -515,15 +464,10 @@ func TestChainService_EverythingOptimistic(t *testing.T) {
 		EnableStartOptimistic: true,
 	})
 	defer resetFn()
-	beaconDB := testDB.SetupDB(t)
-	ctx := context.Background()

 	genesis := util.NewBeaconBlock()
 	genesisRoot, err := genesis.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
-	util.SaveBlock(t, ctx, beaconDB, genesis)
-
 	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
 	headBlock := util.NewBeaconBlock()
 	headBlock.Block.Slot = finalizedSlot
@@ -534,21 +478,17 @@ func TestChainService_EverythingOptimistic(t *testing.T) {
 	require.NoError(t, headState.SetGenesisValidatorsRoot(params.BeaconConfig().ZeroHash[:]))
 	headRoot, err := headBlock.Block.HashTreeRoot()
 	require.NoError(t, err)
+
+	c, tr := minimalTestService(t, WithFinalizedStateAtStartUp(headState))
+	ctx, beaconDB, stateGen := tr.ctx, tr.db, tr.sg
+
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
+	util.SaveBlock(t, ctx, beaconDB, genesis)
 	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
 	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
 	util.SaveBlock(t, ctx, beaconDB, headBlock)
 	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)
-	fc := doublylinkedtree.New()
-	stateGen := stategen.New(beaconDB, fc)
-	c, err := NewService(ctx,
-		WithForkChoiceStore(fc),
-		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, beaconDB.SaveLastValidatedCheckpoint(ctx, &ethpb.Checkpoint{Epoch: slots.ToEpoch(finalizedSlot), Root: headRoot[:]}))
@@ -558,3 +498,19 @@ func TestChainService_EverythingOptimistic(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, true, op)
 }
+
+// MockClockSetter satisfies the ClockSetter interface for testing the conditions where blockchain.Service should
+// call SetGenesis.
+type MockClockSetter struct {
+	G   *startup.Clock
+	Err error
+}
+
+var _ startup.ClockSetter = &MockClockSetter{}
+
+// SetClock satisfies the ClockSetter interface.
+// The value is written to an exported field 'G' so that it can be accessed in tests.
+func (s *MockClockSetter) SetClock(g *startup.Clock) error {
+	s.G = g
+	return s.Err
+}
--- a/beacon-chain/blockchain/setup_test.go
+++ b/beacon-chain/blockchain/setup_test.go
@@ -0,0 +1,115 @@
+package blockchain
+
+import (
+	"context"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v4/async/event"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache/depositcache"
+	statefeed "github.com/prysmaticlabs/prysm/v4/beacon-chain/core/feed/state"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db"
+	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/attestations"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/operations/blstoexec"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/p2p"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/startup"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+	"google.golang.org/protobuf/proto"
+)
+
+type mockBeaconNode struct {
+	stateFeed *event.Feed
+}
+
+// StateFeed mocks the same method in the beacon node.
+func (mbn *mockBeaconNode) StateFeed() *event.Feed {
+	if mbn.stateFeed == nil {
+		mbn.stateFeed = new(event.Feed)
+	}
+	return mbn.stateFeed
+}
+
+type mockBroadcaster struct {
+	broadcastCalled bool
+}
+
+func (mb *mockBroadcaster) Broadcast(_ context.Context, _ proto.Message) error {
+	mb.broadcastCalled = true
+	return nil
+}
+
+func (mb *mockBroadcaster) BroadcastAttestation(_ context.Context, _ uint64, _ *ethpb.Attestation) error {
+	mb.broadcastCalled = true
+	return nil
+}
+
+func (mb *mockBroadcaster) BroadcastSyncCommitteeMessage(_ context.Context, _ uint64, _ *ethpb.SyncCommitteeMessage) error {
+	mb.broadcastCalled = true
+	return nil
+}
+
+func (mb *mockBroadcaster) BroadcastBLSChanges(_ context.Context, _ []*ethpb.SignedBLSToExecutionChange) {
+}
+
+var _ p2p.Broadcaster = (*mockBroadcaster)(nil)
+
+type testServiceRequirements struct {
+	ctx     context.Context
+	db      db.Database
+	fcs     forkchoice.ForkChoicer
+	sg      *stategen.State
+	notif   statefeed.Notifier
+	cs      *startup.ClockSynchronizer
+	attPool attestations.Pool
+	attSrv  *attestations.Service
+	blsPool *blstoexec.Pool
+	dc      *depositcache.DepositCache
+}
+
+func minimalTestService(t *testing.T, opts ...Option) (*Service, *testServiceRequirements) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	fcs := doublylinkedtree.New()
+	sg := stategen.New(beaconDB, fcs)
+	notif := &mockBeaconNode{}
+	fcs.SetBalancesByRooter(sg.ActiveNonSlashedBalancesByRoot)
+	cs := startup.NewClockSynchronizer()
+	attPool := attestations.NewPool()
+	attSrv, err := attestations.NewService(ctx, &attestations.Config{Pool: attPool})
+	require.NoError(t, err)
+	blsPool := blstoexec.NewPool()
+	dc, err := depositcache.New()
+	require.NoError(t, err)
+	req := &testServiceRequirements{
+		ctx:     ctx,
+		db:      beaconDB,
+		fcs:     fcs,
+		sg:      sg,
+		notif:   notif,
+		cs:      cs,
+		attPool: attPool,
+		attSrv:  attSrv,
+		blsPool: blsPool,
+		dc:      dc,
+	}
+	defOpts := []Option{WithDatabase(req.db),
+		WithStateNotifier(req.notif),
+		WithStateGen(req.sg),
+		WithForkChoiceStore(req.fcs),
+		WithClockSynchronizer(req.cs),
+		WithAttestationPool(req.attPool),
+		WithAttestationService(req.attSrv),
+		WithBLSToExecPool(req.blsPool),
+		WithDepositCache(dc),
+	}
+	// append the variadic opts so they override the defaults by being processed afterwards
+	opts = append(defOpts, opts...)
+	s, err := NewService(req.ctx, opts...)
+
+	require.NoError(t, err)
+	return s, req
+}
--- a/beacon-chain/blockchain/testing/mock.go
+++ b/beacon-chain/blockchain/testing/mock.go
@@ -320,7 +320,7 @@ func (_ *ChainService) ReceiveAttestation(_ context.Context, _ *ethpb.Attestatio
 }

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

@@ -594,6 +594,6 @@ func (s *ChainService) FinalizedBlockHash() [32]byte {
 }

 // UnrealizedJustifiedPayloadBlockHash mocks the same method in the chain service
-func (s *ChainService) UnrealizedJustifiedPayloadBlockHash() ([32]byte, error) {
-	return [32]byte{}, nil
+func (s *ChainService) UnrealizedJustifiedPayloadBlockHash() [32]byte {
+	return [32]byte{}
 }
--- a/beacon-chain/builder/BUILD.bazel
+++ b/beacon-chain/builder/BUILD.bazel
@@ -12,11 +12,13 @@ go_library(
    deps = [
        "//api/client/builder:go_default_library",
        "//beacon-chain/blockchain:go_default_library",
+        "//beacon-chain/cache:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//cmd/beacon-chain/flags:go_default_library",
        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//encoding/bytesutil:go_default_library",
+        "//monitoring/tracing:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
--- a/beacon-chain/builder/option.go
+++ b/beacon-chain/builder/option.go
@@ -3,6 +3,7 @@ package builder
 import (
 	"github.com/prysmaticlabs/prysm/v4/api/client/builder"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/v4/cmd/beacon-chain/flags"
 	"github.com/urfave/cli/v2"
@@ -50,3 +51,11 @@ func WithDatabase(beaconDB db.HeadAccessDatabase) Option {
 		return nil
 	}
 }
+
+// WithRegistrationCache uses a cache for the validator registrations instead of a persistent db.
+func WithRegistrationCache() Option {
+	return func(s *Service) error {
+		s.registrationCache = cache.NewRegistrationCache()
+		return nil
+	}
+}
--- a/beacon-chain/builder/service.go
+++ b/beacon-chain/builder/service.go
@@ -8,10 +8,12 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/api/client/builder"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v4/monitoring/tracing"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	log "github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
@@ -25,6 +27,7 @@ type BlockBuilder interface {
 	SubmitBlindedBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, error)
 	GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubKey [48]byte) (builder.SignedBid, error)
 	RegisterValidator(ctx context.Context, reg []*ethpb.SignedValidatorRegistrationV1) error
+	RegistrationByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (*ethpb.ValidatorRegistrationV1, error)
 	Configured() bool
 }

@@ -37,10 +40,11 @@ type config struct {

 // Service defines a service that provides a client for interacting with the beacon chain and MEV relay network.
 type Service struct {
-	cfg    *config
-	c      builder.BuilderClient
-	ctx    context.Context
-	cancel context.CancelFunc
+	cfg               *config
+	c                 builder.BuilderClient
+	ctx               context.Context
+	cancel            context.CancelFunc
+	registrationCache *cache.RegistrationCache
 }

 // NewService instantiates a new service.
@@ -77,7 +81,8 @@ func (s *Service) Start() {
 }

 // Stop halts the service.
-func (*Service) Stop() error {
+func (s *Service) Stop() error {
+	s.cancel()
 	return nil
 }

@@ -89,6 +94,9 @@ func (s *Service) SubmitBlindedBlock(ctx context.Context, b interfaces.ReadOnlyS
 	defer func() {
 		submitBlindedBlockLatency.Observe(float64(time.Since(start).Milliseconds()))
 	}()
+	if s.c == nil {
+		return nil, ErrNoBuilder
+	}

 	return s.c.SubmitBlindedBlock(ctx, b)
 }
@@ -101,8 +109,14 @@ func (s *Service) GetHeader(ctx context.Context, slot primitives.Slot, parentHas
 	defer func() {
 		getHeaderLatency.Observe(float64(time.Since(start).Milliseconds()))
 	}()
+	if s.c == nil {
+		tracing.AnnotateError(span, ErrNoBuilder)
+		return nil, ErrNoBuilder
+	}

-	return s.c.GetHeader(ctx, slot, parentHash, pubKey)
+	h, err := s.c.GetHeader(ctx, slot, parentHash, pubKey)
+	tracing.AnnotateError(span, err)
+	return h, err
 }

 // Status retrieves the status of the builder relay network.
@@ -124,9 +138,16 @@ func (s *Service) RegisterValidator(ctx context.Context, reg []*ethpb.SignedVali
 	defer func() {
 		registerValidatorLatency.Observe(float64(time.Since(start).Milliseconds()))
 	}()
+	if s.c == nil {
+		return ErrNoBuilder
+	}

+	// should be removed if db is removed
 	idxs := make([]primitives.ValidatorIndex, 0)
 	msgs := make([]*ethpb.ValidatorRegistrationV1, 0)
+
+	indexToRegistration := make(map[primitives.ValidatorIndex]*ethpb.ValidatorRegistrationV1)
+
 	valid := make([]*ethpb.SignedValidatorRegistrationV1, 0)
 	for i := 0; i < len(reg); i++ {
 		r := reg[i]
@@ -140,12 +161,33 @@ func (s *Service) RegisterValidator(ctx context.Context, reg []*ethpb.SignedVali
 		idxs = append(idxs, nx)
 		msgs = append(msgs, r.Message)
 		valid = append(valid, r)
+		indexToRegistration[nx] = r.Message
 	}
 	if err := s.c.RegisterValidator(ctx, valid); err != nil {
 		return errors.Wrap(err, "could not register validator(s)")
 	}

-	return s.cfg.beaconDB.SaveRegistrationsByValidatorIDs(ctx, idxs, msgs)
+	if len(indexToRegistration) != len(msgs) {
+		return errors.New("ids and registrations must be the same length")
+	}
+	if s.registrationCache != nil {
+		s.registrationCache.UpdateIndexToRegisteredMap(ctx, indexToRegistration)
+		return nil
+	} else {
+		return s.cfg.beaconDB.SaveRegistrationsByValidatorIDs(ctx, idxs, msgs)
+	}
+}
+
+// RegistrationByValidatorID returns either the values from the cache or db.
+func (s *Service) RegistrationByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (*ethpb.ValidatorRegistrationV1, error) {
+	if s.registrationCache != nil {
+		return s.registrationCache.RegistrationByIndex(id)
+	} else {
+		if s.cfg == nil || s.cfg.beaconDB == nil {
+			return nil, errors.New("nil beacon db")
+		}
+		return s.cfg.beaconDB.RegistrationByValidatorID(ctx, id)
+	}
 }

 // Configured returns true if the user has configured a builder client.
--- a/beacon-chain/builder/service_test.go
+++ b/beacon-chain/builder/service_test.go
@@ -3,6 +3,7 @@ package builder
 import (
 	"context"
 	"testing"
+	"time"

 	buildertesting "github.com/prysmaticlabs/prysm/v4/api/client/builder/testing"
 	blockchainTesting "github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain/testing"
@@ -37,3 +38,33 @@ func Test_RegisterValidator(t *testing.T) {
 	require.NoError(t, s.RegisterValidator(ctx, []*eth.SignedValidatorRegistrationV1{{Message: &eth.ValidatorRegistrationV1{Pubkey: pubkey[:], FeeRecipient: feeRecipient[:]}}}))
 	assert.Equal(t, true, builder.RegisteredVals[pubkey])
 }
+
+func Test_RegisterValidator_WithCache(t *testing.T) {
+	ctx := context.Background()
+	headFetcher := &blockchainTesting.ChainService{}
+	builder := buildertesting.NewClient()
+	s, err := NewService(ctx, WithRegistrationCache(), WithHeadFetcher(headFetcher), WithBuilderClient(&builder))
+	require.NoError(t, err)
+	pubkey := bytesutil.ToBytes48([]byte("pubkey"))
+	var feeRecipient [20]byte
+	reg := &eth.ValidatorRegistrationV1{Pubkey: pubkey[:], Timestamp: uint64(time.Now().UTC().Unix()), FeeRecipient: feeRecipient[:]}
+	require.NoError(t, s.RegisterValidator(ctx, []*eth.SignedValidatorRegistrationV1{{Message: reg}}))
+	registration, err := s.registrationCache.RegistrationByIndex(0)
+	require.NoError(t, err)
+	require.DeepEqual(t, reg, registration)
+}
+
+func Test_BuilderMethodsWithouClient(t *testing.T) {
+	s, err := NewService(context.Background())
+	require.NoError(t, err)
+	assert.Equal(t, false, s.Configured())
+
+	_, err = s.GetHeader(context.Background(), 0, [32]byte{}, [48]byte{})
+	assert.ErrorContains(t, ErrNoBuilder.Error(), err)
+
+	_, err = s.SubmitBlindedBlock(context.Background(), nil)
+	assert.ErrorContains(t, ErrNoBuilder.Error(), err)
+
+	err = s.RegisterValidator(context.Background(), nil)
+	assert.ErrorContains(t, ErrNoBuilder.Error(), err)
+}
--- a/beacon-chain/builder/testing/BUILD.bazel
+++ b/beacon-chain/builder/testing/BUILD.bazel
@@ -8,6 +8,8 @@ go_library(
    visibility = ["//visibility:public"],
    deps = [
        "//api/client/builder:go_default_library",
+        "//beacon-chain/cache:go_default_library",
+        "//beacon-chain/db:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/blocks:go_default_library",
        "//consensus-types/interfaces:go_default_library",
--- a/beacon-chain/builder/testing/mock.go
+++ b/beacon-chain/builder/testing/mock.go
@@ -2,10 +2,11 @@ package testing

 import (
 	"context"
-	"math/big"

 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/api/client/builder"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
@@ -15,6 +16,11 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 )

+// Config defines a config struct for dependencies into the service.
+type Config struct {
+	BeaconDB db.HeadAccessDatabase
+}
+
 // MockBuilderService to mock builder.
 type MockBuilderService struct {
 	HasConfigured         bool
@@ -23,8 +29,10 @@ type MockBuilderService struct {
 	ErrSubmitBlindedBlock error
 	Bid                   *ethpb.SignedBuilderBid
 	BidCapella            *ethpb.SignedBuilderBidCapella
+	RegistrationCache     *cache.RegistrationCache
 	ErrGetHeader          error
 	ErrRegisterValidator  error
+	Cfg                   *Config
 }

 // Configured for mocking.
@@ -41,7 +49,7 @@ func (s *MockBuilderService) SubmitBlindedBlock(_ context.Context, _ interfaces.
 		}
 		return w, s.ErrSubmitBlindedBlock
 	}
-	w, err := blocks.WrappedExecutionPayloadCapella(s.PayloadCapella, big.NewInt(0))
+	w, err := blocks.WrappedExecutionPayloadCapella(s.PayloadCapella, 0)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not wrap capella payload")
 	}
@@ -49,8 +57,8 @@ func (s *MockBuilderService) SubmitBlindedBlock(_ context.Context, _ interfaces.
 }

 // GetHeader for mocking.
-func (s *MockBuilderService) GetHeader(ctx context.Context, slot primitives.Slot, hr [32]byte, pb [48]byte) (builder.SignedBid, error) {
-	if slots.ToEpoch(slot) >= params.BeaconConfig().CapellaForkEpoch {
+func (s *MockBuilderService) GetHeader(_ context.Context, slot primitives.Slot, _ [32]byte, _ [48]byte) (builder.SignedBid, error) {
+	if slots.ToEpoch(slot) >= params.BeaconConfig().CapellaForkEpoch || s.BidCapella != nil {
 		return builder.WrappedSignedBuilderBidCapella(s.BidCapella)
 	}
 	w, err := builder.WrappedSignedBuilderBid(s.Bid)
@@ -60,6 +68,17 @@ func (s *MockBuilderService) GetHeader(ctx context.Context, slot primitives.Slot
 	return w, s.ErrGetHeader
 }

+// RegistrationByValidatorID returns either the values from the cache or db.
+func (s *MockBuilderService) RegistrationByValidatorID(ctx context.Context, id primitives.ValidatorIndex) (*ethpb.ValidatorRegistrationV1, error) {
+	if s.RegistrationCache != nil {
+		return s.RegistrationCache.RegistrationByIndex(id)
+	}
+	if s.Cfg.BeaconDB != nil {
+		return s.Cfg.BeaconDB.RegistrationByValidatorID(ctx, id)
+	}
+	return nil, cache.ErrNotFoundRegistration
+}
+
 // RegisterValidator for mocking.
 func (s *MockBuilderService) RegisterValidator(context.Context, []*ethpb.SignedValidatorRegistrationV1) error {
 	return s.ErrRegisterValidator
--- a/beacon-chain/cache/BUILD.bazel
+++ b/beacon-chain/cache/BUILD.bazel
@@ -17,6 +17,7 @@ go_library(
        "proposer_indices.go",
        "proposer_indices_disabled.go",  # keep
        "proposer_indices_type.go",
+        "registration.go",
        "skip_slot_cache.go",
        "subnet_ids.go",
        "sync_committee.go",
@@ -33,6 +34,7 @@ go_library(
    deps = [
        "//beacon-chain/state:go_default_library",
        "//cache/lru:go_default_library",
+        "//config/fieldparams:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//container/slice:go_default_library",
@@ -47,6 +49,7 @@ go_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_sirupsen_logrus//:go_default_library",
        "@io_k8s_client_go//tools/cache:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
    ],
@@ -64,6 +67,7 @@ go_test(
        "committee_test.go",
        "payload_id_test.go",
        "proposer_indices_test.go",
+        "registration_test.go",
        "skip_slot_cache_test.go",
        "subnet_ids_test.go",
        "sync_committee_head_state_test.go",
@@ -82,6 +86,7 @@ go_test(
        "//testing/assert:go_default_library",
        "//testing/require:go_default_library",
        "//testing/util:go_default_library",
+        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
        "@com_github_google_gofuzz//:go_default_library",
        "@org_golang_google_protobuf//proto:go_default_library",
    ],
--- a/beacon-chain/cache/active_balance.go
+++ b/beacon-chain/cache/active_balance.go
@@ -42,9 +42,16 @@ type BalanceCache struct {

 // NewEffectiveBalanceCache creates a new effective balance cache for storing/accessing total balance by epoch.
 func NewEffectiveBalanceCache() *BalanceCache {
-	return &BalanceCache{
-		cache: lruwrpr.New(maxBalanceCacheSize),
-	}
+	c := &BalanceCache{}
+	c.Clear()
+	return c
+}
+
+// Clear resets the SyncCommitteeCache to its initial state
+func (c *BalanceCache) Clear() {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache = lruwrpr.New(maxBalanceCacheSize)
 }

 // AddTotalEffectiveBalance adds a new total effective balance entry for current balance for state `st` into the cache.
--- a/beacon-chain/cache/active_balance_disabled.go
+++ b/beacon-chain/cache/active_balance_disabled.go
@@ -3,16 +3,11 @@
 package cache

 import (
-	"sync"
-
-	lru "github.com/hashicorp/golang-lru"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 )

 // FakeBalanceCache is a fake struct with 1 LRU cache for looking up balance by epoch.
 type FakeBalanceCache struct {
-	cache *lru.Cache
-	lock  sync.RWMutex
 }

 // NewEffectiveBalanceCache creates a new effective balance cache for storing/accessing total balance by epoch.
@@ -29,3 +24,8 @@ func (c *FakeBalanceCache) AddTotalEffectiveBalance(st state.ReadOnlyBeaconState
 func (c *FakeBalanceCache) Get(st state.ReadOnlyBeaconState) (uint64, error) {
 	return 0, nil
 }
+
+// Clear is a stub.
+func (c *FakeBalanceCache) Clear() {
+	return
+}
--- a/beacon-chain/cache/committee.go
+++ b/beacon-chain/cache/committee.go
@@ -56,10 +56,17 @@ func committeeKeyFn(obj interface{}) (string, error) {

 // NewCommitteesCache creates a new committee cache for storing/accessing shuffled indices of a committee.
 func NewCommitteesCache() *CommitteeCache {
-	return &CommitteeCache{
-		CommitteeCache: lruwrpr.New(maxCommitteesCacheSize),
-		inProgress:     make(map[string]bool),
-	}
+	cc := &CommitteeCache{}
+	cc.Clear()
+	return cc
+}
+
+// Clear resets the CommitteeCache to its initial state
+func (c *CommitteeCache) Clear() {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.CommitteeCache = lruwrpr.New(maxCommitteesCacheSize)
+	c.inProgress = make(map[string]bool)
 }

 // Committee fetches the shuffled indices by slot and committee index. Every list of indices
--- a/beacon-chain/cache/committee_disabled.go
+++ b/beacon-chain/cache/committee_disabled.go
@@ -69,3 +69,8 @@ func (c *FakeCommitteeCache) MarkInProgress(seed [32]byte) error {
 func (c *FakeCommitteeCache) MarkNotInProgress(seed [32]byte) error {
 	return nil
 }
+
+// Clear is a stub.
+func (c *FakeCommitteeCache) Clear() {
+	return
+}
--- a/beacon-chain/cache/depositcache/deposits_cache.go
+++ b/beacon-chain/cache/depositcache/deposits_cache.go
@@ -129,7 +129,7 @@ func (dc *DepositCache) InsertDepositContainers(ctx context.Context, ctrs []*eth
 }

 // InsertFinalizedDeposits inserts deposits up to eth1DepositIndex (inclusive) into the finalized deposits cache.
-func (dc *DepositCache) InsertFinalizedDeposits(ctx context.Context, eth1DepositIndex int64) {
+func (dc *DepositCache) InsertFinalizedDeposits(ctx context.Context, eth1DepositIndex int64) error {
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.InsertFinalizedDeposits")
 	defer span.End()
 	dc.depositsLock.Lock()
@@ -141,7 +141,7 @@ func (dc *DepositCache) InsertFinalizedDeposits(ctx context.Context, eth1Deposit
 	// Don't insert into finalized trie if there is no deposit to
 	// insert.
 	if len(dc.deposits) == 0 {
-		return
+		return nil
 	}
 	// In the event we have less deposits than we need to
 	// finalize we finalize till the index on which we do have it.
@@ -151,7 +151,7 @@ func (dc *DepositCache) InsertFinalizedDeposits(ctx context.Context, eth1Deposit
 	// If we finalize to some lower deposit index, we
 	// ignore it.
 	if int(eth1DepositIndex) < insertIndex {
-		return
+		return nil
 	}
 	for _, d := range dc.deposits {
 		if d.Index <= dc.finalizedDeposits.MerkleTrieIndex {
@@ -162,12 +162,10 @@ func (dc *DepositCache) InsertFinalizedDeposits(ctx context.Context, eth1Deposit
 		}
 		depHash, err := d.Deposit.Data.HashTreeRoot()
 		if err != nil {
-			log.WithError(err).Error("Could not hash deposit data. Finalized deposit cache not updated.")
-			return
+			return errors.Wrap(err, "could not hash deposit data")
 		}
 		if err = depositTrie.Insert(depHash[:], insertIndex); err != nil {
-			log.WithError(err).Error("Could not insert deposit hash")
-			return
+			return errors.Wrap(err, "could not insert deposit hash")
 		}
 		insertIndex++
 	}
@@ -176,6 +174,7 @@ func (dc *DepositCache) InsertFinalizedDeposits(ctx context.Context, eth1Deposit
 		Deposits:        depositTrie,
 		MerkleTrieIndex: eth1DepositIndex,
 	}
+	return nil
 }

 // AllDepositContainers returns all historical deposit containers.
--- a/beacon-chain/cache/depositcache/deposits_cache_test.go
+++ b/beacon-chain/cache/depositcache/deposits_cache_test.go
@@ -416,7 +416,7 @@ func TestFinalizedDeposits_DepositsCachedCorrectly(t *testing.T) {
 		Index: 3,
 	})

-	dc.InsertFinalizedDeposits(context.Background(), 2)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 2))

 	cachedDeposits := dc.FinalizedDeposits(context.Background())
 	require.NotNil(t, cachedDeposits, "Deposits not cached")
@@ -474,9 +474,9 @@ func TestFinalizedDeposits_UtilizesPreviouslyCachedDeposits(t *testing.T) {
 		Index: 2,
 	}
 	dc.deposits = oldFinalizedDeposits
-	dc.InsertFinalizedDeposits(context.Background(), 1)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 1))

-	dc.InsertFinalizedDeposits(context.Background(), 2)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 2))

 	dc.deposits = append(dc.deposits, []*ethpb.DepositContainer{newFinalizedDeposit}...)

@@ -503,7 +503,7 @@ func TestFinalizedDeposits_HandleZeroDeposits(t *testing.T) {
 	dc, err := New()
 	require.NoError(t, err)

-	dc.InsertFinalizedDeposits(context.Background(), 2)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 2))

 	cachedDeposits := dc.FinalizedDeposits(context.Background())
 	require.NotNil(t, cachedDeposits, "Deposits not cached")
@@ -548,7 +548,7 @@ func TestFinalizedDeposits_HandleSmallerThanExpectedDeposits(t *testing.T) {
 	}
 	dc.deposits = finalizedDeposits

-	dc.InsertFinalizedDeposits(context.Background(), 5)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 5))

 	cachedDeposits := dc.FinalizedDeposits(context.Background())
 	require.NotNil(t, cachedDeposits, "Deposits not cached")
@@ -623,10 +623,10 @@ func TestFinalizedDeposits_HandleLowerEth1DepositIndex(t *testing.T) {
 	}
 	dc.deposits = finalizedDeposits

-	dc.InsertFinalizedDeposits(context.Background(), 5)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 5))

 	// Reinsert finalized deposits with a lower index.
-	dc.InsertFinalizedDeposits(context.Background(), 2)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 2))

 	cachedDeposits := dc.FinalizedDeposits(context.Background())
 	require.NotNil(t, cachedDeposits, "Deposits not cached")
@@ -694,7 +694,7 @@ func TestNonFinalizedDeposits_ReturnsAllNonFinalizedDeposits(t *testing.T) {
 			},
 			Index: 3,
 		})
-	dc.InsertFinalizedDeposits(context.Background(), 1)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 1))

 	deps := dc.NonFinalizedDeposits(context.Background(), 1, nil)
 	assert.Equal(t, 2, len(deps))
@@ -751,7 +751,7 @@ func TestNonFinalizedDeposits_ReturnsNonFinalizedDepositsUpToBlockNumber(t *test
 			},
 			Index: 3,
 		})
-	dc.InsertFinalizedDeposits(context.Background(), 1)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 1))

 	deps := dc.NonFinalizedDeposits(context.Background(), 1, big.NewInt(10))
 	assert.Equal(t, 1, len(deps))
@@ -799,12 +799,12 @@ func TestFinalizedDeposits_ReturnsTrieCorrectly(t *testing.T) {
 	assert.NoError(t, err)

 	// Perform this in a non-sensical ordering
-	dc.InsertFinalizedDeposits(context.Background(), 10)
-	dc.InsertFinalizedDeposits(context.Background(), 2)
-	dc.InsertFinalizedDeposits(context.Background(), 3)
-	dc.InsertFinalizedDeposits(context.Background(), 4)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 10))
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 2))
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 3))
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 4))

-	// Mimick finalized deposit trie fetch.
+	// Mimic finalized deposit trie fetch.
 	fd := dc.FinalizedDeposits(context.Background())
 	deps := dc.NonFinalizedDeposits(context.Background(), fd.MerkleTrieIndex, big.NewInt(14))
 	insertIndex := fd.MerkleTrieIndex + 1
@@ -817,9 +817,9 @@ func TestFinalizedDeposits_ReturnsTrieCorrectly(t *testing.T) {
 		}
 		insertIndex++
 	}
-	dc.InsertFinalizedDeposits(context.Background(), 15)
-	dc.InsertFinalizedDeposits(context.Background(), 15)
-	dc.InsertFinalizedDeposits(context.Background(), 14)
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 15))
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 15))
+	require.NoError(t, dc.InsertFinalizedDeposits(context.Background(), 14))

 	fd = dc.FinalizedDeposits(context.Background())
 	deps = dc.NonFinalizedDeposits(context.Background(), fd.MerkleTrieIndex, big.NewInt(30))
--- a/beacon-chain/cache/error.go
+++ b/beacon-chain/cache/error.go
@@ -1,6 +1,6 @@
 package cache

-import "errors"
+import "github.com/pkg/errors"

 var (
 	// ErrNilValueProvided for when we try to put a nil value in a cache.
@@ -12,4 +12,6 @@ var (
 	// ErrNonExistingSyncCommitteeKey when sync committee key (root) does not exist in cache.
 	ErrNonExistingSyncCommitteeKey   = errors.New("does not exist sync committee key")
 	errNotSyncCommitteeIndexPosition = errors.New("not syncCommitteeIndexPosition struct")
+	// ErrNotFoundRegistration when validator registration does not exist in cache.
+	ErrNotFoundRegistration = errors.Wrap(ErrNotFound, "no validator registered")
 )
--- a/beacon-chain/cache/payload_id.go
+++ b/beacon-chain/cache/payload_id.go
@@ -4,35 +4,41 @@ import (
 	"bytes"
 	"sync"

+	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
 )

+const keyLength = 40
 const vIdLength = 8
 const pIdLength = 8
 const vpIdsLength = vIdLength + pIdLength

 // ProposerPayloadIDsCache is a cache of proposer payload IDs.
-// The key is the slot. The value is the concatenation of the proposer and payload IDs. 8 bytes each.
+// The key is the concatenation of the slot and the block root.
+// The value is the concatenation of the proposer and payload IDs, 8 bytes each.
 type ProposerPayloadIDsCache struct {
-	slotToProposerAndPayloadIDs map[[40]byte][vpIdsLength]byte
+	slotToProposerAndPayloadIDs map[[keyLength]byte][vpIdsLength]byte
 	sync.RWMutex
 }

 // NewProposerPayloadIDsCache creates a new proposer payload IDs cache.
 func NewProposerPayloadIDsCache() *ProposerPayloadIDsCache {
 	return &ProposerPayloadIDsCache{
-		slotToProposerAndPayloadIDs: make(map[[40]byte][vpIdsLength]byte),
+		slotToProposerAndPayloadIDs: make(map[[keyLength]byte][vpIdsLength]byte),
 	}
 }

-// GetProposerPayloadIDs returns the proposer and  payload IDs for the given slot.
-func (f *ProposerPayloadIDsCache) GetProposerPayloadIDs(slot primitives.Slot, r [32]byte) (primitives.ValidatorIndex, [8]byte, bool) {
+// GetProposerPayloadIDs returns the proposer and payload IDs for the given slot and head root to build the block.
+func (f *ProposerPayloadIDsCache) GetProposerPayloadIDs(
+	slot primitives.Slot,
+	r [fieldparams.RootLength]byte,
+) (primitives.ValidatorIndex, [pIdLength]byte, bool) {
 	f.RLock()
 	defer f.RUnlock()
 	ids, ok := f.slotToProposerAndPayloadIDs[idKey(slot, r)]
 	if !ok {
-		return 0, [8]byte{}, false
+		return 0, [pIdLength]byte{}, false
 	}
 	vId := ids[:vIdLength]

@@ -43,8 +49,13 @@ func (f *ProposerPayloadIDsCache) GetProposerPayloadIDs(slot primitives.Slot, r
 	return primitives.ValidatorIndex(bytesutil.BytesToUint64BigEndian(vId)), pId, true
 }

-// SetProposerAndPayloadIDs sets the proposer and payload IDs for the given slot.
-func (f *ProposerPayloadIDsCache) SetProposerAndPayloadIDs(slot primitives.Slot, vId primitives.ValidatorIndex, pId [8]byte, r [32]byte) {
+// SetProposerAndPayloadIDs sets the proposer and payload IDs for the given slot and head root to build block.
+func (f *ProposerPayloadIDsCache) SetProposerAndPayloadIDs(
+	slot primitives.Slot,
+	vId primitives.ValidatorIndex,
+	pId [pIdLength]byte,
+	r [fieldparams.RootLength]byte,
+) {
 	f.Lock()
 	defer f.Unlock()
 	var vIdBytes [vIdLength]byte
@@ -63,7 +74,7 @@ func (f *ProposerPayloadIDsCache) SetProposerAndPayloadIDs(slot primitives.Slot,
 	}
 }

-// PrunePayloadIDs removes the payload id entries that's current than input slot.
+// PrunePayloadIDs removes the payload ID entries older than input slot.
 func (f *ProposerPayloadIDsCache) PrunePayloadIDs(slot primitives.Slot) {
 	f.Lock()
 	defer f.Unlock()
@@ -76,8 +87,8 @@ func (f *ProposerPayloadIDsCache) PrunePayloadIDs(slot primitives.Slot) {
 	}
 }

-func idKey(slot primitives.Slot, r [32]byte) [40]byte {
-	var k [40]byte
+func idKey(slot primitives.Slot, r [fieldparams.RootLength]byte) [keyLength]byte {
+	var k [keyLength]byte
 	copy(k[:], append(bytesutil.Uint64ToBytesBigEndian(uint64(slot)), r[:]...))
 	return k
 }
--- a/beacon-chain/cache/proposer_indices.go
+++ b/beacon-chain/cache/proposer_indices.go
@@ -46,9 +46,16 @@ func proposerIndicesKeyFn(obj interface{}) (string, error) {

 // NewProposerIndicesCache creates a new proposer indices cache for storing/accessing proposer index assignments of an epoch.
 func NewProposerIndicesCache() *ProposerIndicesCache {
-	return &ProposerIndicesCache{
-		proposerIndicesCache: cache.NewFIFO(proposerIndicesKeyFn),
-	}
+	c := &ProposerIndicesCache{}
+	c.Clear()
+	return c
+}
+
+// Clear resets the ProposerIndicesCache to its initial state
+func (c *ProposerIndicesCache) Clear() {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.proposerIndicesCache = cache.NewFIFO(proposerIndicesKeyFn)
 }

 // AddProposerIndices adds ProposerIndices object to the cache.
--- a/beacon-chain/cache/proposer_indices_disabled.go
+++ b/beacon-chain/cache/proposer_indices_disabled.go
@@ -33,3 +33,7 @@ func (c *FakeProposerIndicesCache) HasProposerIndices(r [32]byte) (bool, error)
 func (c *FakeProposerIndicesCache) Len() int {
 	return 0
 }
+
+// Clear is a stub.
+func (c *FakeProposerIndicesCache) Clear() {
+}
--- a/beacon-chain/cache/registration.go
+++ b/beacon-chain/cache/registration.go
@@ -0,0 +1,55 @@
+package cache
+
+import (
+	"context"
+	"sync"
+
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"go.opencensus.io/trace"
+)
+
+// RegistrationCache is used to store the cached results of an Validator Registration request.
+// beacon api /eth/v1/validator/register_validator
+type RegistrationCache struct {
+	indexToRegistration map[primitives.ValidatorIndex]*ethpb.ValidatorRegistrationV1
+	lock                sync.RWMutex
+}
+
+// NewRegistrationCache initializes the map and underlying cache.
+func NewRegistrationCache() *RegistrationCache {
+	return &RegistrationCache{
+		indexToRegistration: make(map[primitives.ValidatorIndex]*ethpb.ValidatorRegistrationV1),
+		lock:                sync.RWMutex{},
+	}
+}
+
+// RegistrationByIndex returns the registration by index in the cache and also removes items in the cache if expired.
+func (regCache *RegistrationCache) RegistrationByIndex(id primitives.ValidatorIndex) (*ethpb.ValidatorRegistrationV1, error) {
+	regCache.lock.RLock()
+	v, ok := regCache.indexToRegistration[id]
+	if !ok {
+		regCache.lock.RUnlock()
+		return nil, errors.Wrapf(ErrNotFoundRegistration, "validator id %d", id)
+	}
+	regCache.lock.RUnlock()
+	return v, nil
+}
+
+// UpdateIndexToRegisteredMap adds or updates values in the cache based on the argument.
+func (regCache *RegistrationCache) UpdateIndexToRegisteredMap(ctx context.Context, m map[primitives.ValidatorIndex]*ethpb.ValidatorRegistrationV1) {
+	_, span := trace.StartSpan(ctx, "RegistrationCache.UpdateIndexToRegisteredMap")
+	defer span.End()
+	regCache.lock.Lock()
+	defer regCache.lock.Unlock()
+	for key, value := range m {
+		regCache.indexToRegistration[key] = &ethpb.ValidatorRegistrationV1{
+			Pubkey:       bytesutil.SafeCopyBytes(value.Pubkey),
+			FeeRecipient: bytesutil.SafeCopyBytes(value.FeeRecipient),
+			GasLimit:     value.GasLimit,
+			Timestamp:    value.Timestamp,
+		}
+	}
+}
--- a/beacon-chain/cache/registration_test.go
+++ b/beacon-chain/cache/registration_test.go
@@ -0,0 +1,46 @@
+package cache
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+)
+
+func TestRegistrationCache(t *testing.T) {
+	pubkey, err := hexutil.Decode("0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
+	require.NoError(t, err)
+	validatorIndex := primitives.ValidatorIndex(1)
+	cache := NewRegistrationCache()
+	m := make(map[primitives.ValidatorIndex]*ethpb.ValidatorRegistrationV1)
+
+	m[validatorIndex] = &ethpb.ValidatorRegistrationV1{
+		FeeRecipient: []byte{},
+		GasLimit:     100,
+		Timestamp:    uint64(time.Now().Unix()),
+		Pubkey:       pubkey,
+	}
+	cache.UpdateIndexToRegisteredMap(context.Background(), m)
+	reg, err := cache.RegistrationByIndex(validatorIndex)
+	require.NoError(t, err)
+	require.Equal(t, string(reg.Pubkey), string(pubkey))
+	t.Run("successfully updates", func(t *testing.T) {
+		pubkey, err := hexutil.Decode("0x88247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
+		require.NoError(t, err)
+		validatorIndex2 := primitives.ValidatorIndex(2)
+		m[validatorIndex2] = &ethpb.ValidatorRegistrationV1{
+			FeeRecipient: []byte{},
+			GasLimit:     100,
+			Timestamp:    uint64(time.Now().Unix()),
+			Pubkey:       pubkey,
+		}
+		cache.UpdateIndexToRegisteredMap(context.Background(), m)
+		reg, err := cache.RegistrationByIndex(validatorIndex2)
+		require.NoError(t, err)
+		require.Equal(t, string(reg.Pubkey), string(pubkey))
+	})
+}
--- a/beacon-chain/cache/sync_committee.go
+++ b/beacon-chain/cache/sync_committee.go
@@ -4,12 +4,14 @@ package cache

 import (
 	"sync"
+	"sync/atomic"

 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	log "github.com/sirupsen/logrus"
 	"k8s.io/client-go/tools/cache"
 )

@@ -31,8 +33,9 @@ var (
 // SyncCommitteeCache utilizes a FIFO cache to sufficiently cache validator position within sync committee.
 // It is thread safe with concurrent read write.
 type SyncCommitteeCache struct {
-	cache *cache.FIFO
-	lock  sync.RWMutex
+	cache   *cache.FIFO
+	lock    sync.RWMutex
+	cleared *atomic.Uint64
 }

 // Index position of all validators in sync committee where `currentSyncCommitteeRoot` is the
@@ -51,9 +54,17 @@ type positionInCommittee struct {

 // NewSyncCommittee initializes and returns a new SyncCommitteeCache.
 func NewSyncCommittee() *SyncCommitteeCache {
-	return &SyncCommitteeCache{
-		cache: cache.NewFIFO(keyFn),
-	}
+	c := &SyncCommitteeCache{cleared: &atomic.Uint64{}}
+	c.Clear()
+	return c
+}
+
+// Clear resets the SyncCommitteeCache to its initial state
+func (s *SyncCommitteeCache) Clear() {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	s.cleared.Add(1)
+	s.cache = cache.NewFIFO(keyFn)
 }

 // CurrentPeriodIndexPosition returns current period index position of a validator index with respect with
@@ -123,6 +134,10 @@ func (s *SyncCommitteeCache) idxPositionInCommittee(
 // current epoch and next epoch. This should be called when `current_sync_committee` and `next_sync_committee`
 // change and that happens every `EPOCHS_PER_SYNC_COMMITTEE_PERIOD`.
 func (s *SyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoot [32]byte, st state.BeaconState) error {
+	// since we call UpdatePositionsInCommittee asynchronously, keep track of the cache value
+	// seen at the beginning of the routine and compare at the end before updating. If the underlying value has been
+	// cycled (new address), don't update it.
+	clearCount := s.cleared.Load()
 	csc, err := st.CurrentSyncCommittee()
 	if err != nil {
 		return err
@@ -162,6 +177,10 @@ func (s *SyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoo

 	s.lock.Lock()
 	defer s.lock.Unlock()
+	if clearCount != s.cleared.Load() {
+		log.Warn("cache rotated during async committee update operation - abandoning cache update")
+		return nil
+	}

 	if err := s.cache.Add(&syncCommitteeIndexPosition{
 		currentSyncCommitteeRoot: syncCommitteeBoundaryRoot,
--- a/beacon-chain/cache/sync_committee_disabled.go
+++ b/beacon-chain/cache/sync_committee_disabled.go
@@ -30,3 +30,8 @@ func (s *FakeSyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx p
 func (s *FakeSyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoot [32]byte, state state.BeaconState) error {
 	return nil
 }
+
+// Clear -- fake.
+func (s *FakeSyncCommitteeCache) Clear() {
+	return
+}
--- a/beacon-chain/core/altair/epoch_precompute.go
+++ b/beacon-chain/core/altair/epoch_precompute.go
@@ -13,6 +13,15 @@ import (
 	"go.opencensus.io/trace"
 )

+// AttDelta contains rewards and penalties for a single attestation.
+type AttDelta struct {
+	HeadReward    uint64
+	SourceReward  uint64
+	SourcePenalty uint64
+	TargetReward  uint64
+	TargetPenalty uint64
+}
+
 // InitializePrecomputeValidators precomputes individual validator for its attested balances and the total sum of validators attested balances of the epoch.
 func InitializePrecomputeValidators(ctx context.Context, beaconState state.BeaconState) ([]*precompute.Validator, *precompute.Balance, error) {
 	ctx, span := trace.StartSpan(ctx, "altair.InitializePrecomputeValidators")
@@ -208,7 +217,7 @@ func ProcessEpochParticipation(
 }

 // ProcessRewardsAndPenaltiesPrecompute processes the rewards and penalties of individual validator.
-// This is an optimized version by passing in precomputed validator attesting records and and total epoch balances.
+// This is an optimized version by passing in precomputed validator attesting records and total epoch balances.
 func ProcessRewardsAndPenaltiesPrecompute(
 	beaconState state.BeaconState,
 	bal *precompute.Balance,
@@ -226,7 +235,7 @@ func ProcessRewardsAndPenaltiesPrecompute(
 		return beaconState, errors.New("validator registries not the same length as state's validator registries")
 	}

-	attsRewards, attsPenalties, err := AttestationsDelta(beaconState, bal, vals)
+	attDeltas, err := AttestationsDelta(beaconState, bal, vals)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get attestation delta")
 	}
@@ -237,11 +246,12 @@ func ProcessRewardsAndPenaltiesPrecompute(

 		// Compute the post balance of the validator after accounting for the
 		// attester and proposer rewards and penalties.
-		balances[i], err = helpers.IncreaseBalanceWithVal(balances[i], attsRewards[i])
+		delta := attDeltas[i]
+		balances[i], err = helpers.IncreaseBalanceWithVal(balances[i], delta.HeadReward+delta.SourceReward+delta.TargetReward)
 		if err != nil {
 			return nil, err
 		}
-		balances[i] = helpers.DecreaseBalanceWithVal(balances[i], attsPenalties[i])
+		balances[i] = helpers.DecreaseBalanceWithVal(balances[i], delta.SourcePenalty+delta.TargetPenalty)

 		vals[i].AfterEpochTransitionBalance = balances[i]
 	}
@@ -255,10 +265,8 @@ func ProcessRewardsAndPenaltiesPrecompute(

 // AttestationsDelta computes and returns the rewards and penalties differences for individual validators based on the
 // voting records.
-func AttestationsDelta(beaconState state.BeaconState, bal *precompute.Balance, vals []*precompute.Validator) (rewards, penalties []uint64, err error) {
-	numOfVals := beaconState.NumValidators()
-	rewards = make([]uint64, numOfVals)
-	penalties = make([]uint64, numOfVals)
+func AttestationsDelta(beaconState state.BeaconState, bal *precompute.Balance, vals []*precompute.Validator) ([]*AttDelta, error) {
+	attDeltas := make([]*AttDelta, len(vals))

 	cfg := params.BeaconConfig()
 	prevEpoch := time.PrevEpoch(beaconState)
@@ -272,29 +280,29 @@ func AttestationsDelta(beaconState state.BeaconState, bal *precompute.Balance, v
 	bias := cfg.InactivityScoreBias
 	inactivityPenaltyQuotient, err := beaconState.InactivityPenaltyQuotient()
 	if err != nil {
-		return nil, nil, err
+		return nil, err
 	}
 	inactivityDenominator := bias * inactivityPenaltyQuotient

 	for i, v := range vals {
-		rewards[i], penalties[i], err = attestationDelta(bal, v, baseRewardMultiplier, inactivityDenominator, leak)
+		attDeltas[i], err = attestationDelta(bal, v, baseRewardMultiplier, inactivityDenominator, leak)
 		if err != nil {
-			return nil, nil, err
+			return nil, err
 		}
 	}

-	return rewards, penalties, nil
+	return attDeltas, nil
 }

 func attestationDelta(
 	bal *precompute.Balance,
 	val *precompute.Validator,
 	baseRewardMultiplier, inactivityDenominator uint64,
-	inactivityLeak bool) (reward, penalty uint64, err error) {
+	inactivityLeak bool) (*AttDelta, error) {
 	eligible := val.IsActivePrevEpoch || (val.IsSlashed && !val.IsWithdrawableCurrentEpoch)
 	// Per spec `ActiveCurrentEpoch` can't be 0 to process attestation delta.
 	if !eligible || bal.ActiveCurrentEpoch == 0 {
-		return 0, 0, nil
+		return &AttDelta{}, nil
 	}

 	cfg := params.BeaconConfig()
@@ -307,32 +315,32 @@ func attestationDelta(
 	srcWeight := cfg.TimelySourceWeight
 	tgtWeight := cfg.TimelyTargetWeight
 	headWeight := cfg.TimelyHeadWeight
-	reward, penalty = uint64(0), uint64(0)
+	attDelta := &AttDelta{}
 	// Process source reward / penalty
 	if val.IsPrevEpochSourceAttester && !val.IsSlashed {
 		if !inactivityLeak {
 			n := baseReward * srcWeight * (bal.PrevEpochAttested / increment)
-			reward += n / (activeIncrement * weightDenominator)
+			attDelta.SourceReward += n / (activeIncrement * weightDenominator)
 		}
 	} else {
-		penalty += baseReward * srcWeight / weightDenominator
+		attDelta.SourcePenalty += baseReward * srcWeight / weightDenominator
 	}

 	// Process target reward / penalty
 	if val.IsPrevEpochTargetAttester && !val.IsSlashed {
 		if !inactivityLeak {
 			n := baseReward * tgtWeight * (bal.PrevEpochTargetAttested / increment)
-			reward += n / (activeIncrement * weightDenominator)
+			attDelta.TargetReward += n / (activeIncrement * weightDenominator)
 		}
 	} else {
-		penalty += baseReward * tgtWeight / weightDenominator
+		attDelta.TargetPenalty += baseReward * tgtWeight / weightDenominator
 	}

 	// Process head reward / penalty
 	if val.IsPrevEpochHeadAttester && !val.IsSlashed {
 		if !inactivityLeak {
 			n := baseReward * headWeight * (bal.PrevEpochHeadAttested / increment)
-			reward += n / (activeIncrement * weightDenominator)
+			attDelta.HeadReward += n / (activeIncrement * weightDenominator)
 		}
 	}

@@ -341,10 +349,10 @@ func attestationDelta(
 	if !val.IsPrevEpochTargetAttester || val.IsSlashed {
 		n, err := math.Mul64(effectiveBalance, val.InactivityScore)
 		if err != nil {
-			return 0, 0, err
+			return &AttDelta{}, err
 		}
-		penalty += n / inactivityDenominator
+		attDelta.TargetPenalty += n / inactivityDenominator
 	}

-	return reward, penalty, nil
+	return attDelta, nil
 }
--- a/beacon-chain/core/altair/epoch_precompute_test.go
+++ b/beacon-chain/core/altair/epoch_precompute_test.go
@@ -213,9 +213,16 @@ func TestAttestationsDelta(t *testing.T) {
 	require.NoError(t, err)
 	validators, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
 	require.NoError(t, err)
-	rewards, penalties, err := AttestationsDelta(s, balance, validators)
+	deltas, err := AttestationsDelta(s, balance, validators)
 	require.NoError(t, err)

+	rewards := make([]uint64, len(deltas))
+	penalties := make([]uint64, len(deltas))
+	for i, d := range deltas {
+		rewards[i] = d.HeadReward + d.SourceReward + d.TargetReward
+		penalties[i] = d.SourcePenalty + d.TargetPenalty
+	}
+
 	// Reward amount should increase as validator index increases due to setup.
 	for i := 1; i < len(rewards); i++ {
 		require.Equal(t, true, rewards[i] > rewards[i-1])
@@ -244,9 +251,16 @@ func TestAttestationsDeltaBellatrix(t *testing.T) {
 	require.NoError(t, err)
 	validators, balance, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
 	require.NoError(t, err)
-	rewards, penalties, err := AttestationsDelta(s, balance, validators)
+	deltas, err := AttestationsDelta(s, balance, validators)
 	require.NoError(t, err)

+	rewards := make([]uint64, len(deltas))
+	penalties := make([]uint64, len(deltas))
+	for i, d := range deltas {
+		rewards[i] = d.HeadReward + d.SourceReward + d.TargetReward
+		penalties[i] = d.SourcePenalty + d.TargetPenalty
+	}
+
 	// Reward amount should increase as validator index increases due to setup.
 	for i := 1; i < len(rewards); i++ {
 		require.Equal(t, true, rewards[i] > rewards[i-1])
@@ -285,8 +299,15 @@ func TestProcessRewardsAndPenaltiesPrecompute_Ok(t *testing.T) {
 	}

 	wanted := make([]uint64, s.NumValidators())
-	rewards, penalties, err := AttestationsDelta(s, balance, validators)
+	deltas, err := AttestationsDelta(s, balance, validators)
 	require.NoError(t, err)
+
+	rewards := make([]uint64, len(deltas))
+	penalties := make([]uint64, len(deltas))
+	for i, d := range deltas {
+		rewards[i] = d.HeadReward + d.SourceReward + d.TargetReward
+		penalties[i] = d.SourcePenalty + d.TargetPenalty
+	}
 	for i := range rewards {
 		wanted[i] += rewards[i]
 	}
--- a/beacon-chain/core/altair/epoch_spec.go
+++ b/beacon-chain/core/altair/epoch_spec.go
@@ -12,6 +12,7 @@ import (

 // ProcessSyncCommitteeUpdates  processes sync client committee updates for the beacon state.
 //
+// nolint:dupword
 // Spec code:
 // def process_sync_committee_updates(state: BeaconState) -> None:
 //
@@ -45,6 +46,7 @@ func ProcessSyncCommitteeUpdates(ctx context.Context, beaconState state.BeaconSt

 // ProcessParticipationFlagUpdates processes participation flag updates by rotating current to previous.
 //
+// nolint:dupword
 // Spec code:
 // def process_participation_flag_updates(state: BeaconState) -> None:
 //
--- a/beacon-chain/core/altair/sync_committee.go
+++ b/beacon-chain/core/altair/sync_committee.go
@@ -2,6 +2,7 @@ package altair

 import (
 	"context"
+	goErrors "errors"
 	"fmt"
 	"time"

@@ -22,6 +23,10 @@ import (

 const maxRandomByte = uint64(1<<8 - 1)

+var (
+	ErrTooLate = errors.New("sync message is too late")
+)
+
 // ValidateNilSyncContribution validates the following fields are not nil:
 // -the contribution and proof itself
 // -the message within contribution and proof
@@ -217,7 +222,7 @@ func ValidateSyncMessageTime(slot primitives.Slot, genesisTime time.Time, clockD
 	upperBound := time.Now().Add(clockDisparity)
 	// Verify sync message slot is within the time range.
 	if messageTime.Before(lowerBound) || messageTime.After(upperBound) {
-		return fmt.Errorf(
+		syncErr := fmt.Errorf(
 			"sync message time %v (slot %d) not within allowable range of %v (slot %d) to %v (slot %d)",
 			messageTime,
 			slot,
@@ -226,6 +231,11 @@ func ValidateSyncMessageTime(slot primitives.Slot, genesisTime time.Time, clockD
 			upperBound,
 			uint64(upperBound.Unix()-genesisTime.Unix())/params.BeaconConfig().SecondsPerSlot,
 		)
+		// Wrap error message if sync message is too late.
+		if messageTime.Before(lowerBound) {
+			syncErr = goErrors.Join(ErrTooLate, syncErr)
+		}
+		return syncErr
 	}
 	return nil
 }
--- a/beacon-chain/core/blocks/BUILD.bazel
+++ b/beacon-chain/core/blocks/BUILD.bazel
@@ -28,6 +28,7 @@ go_library(
        "//beacon-chain/state:go_default_library",
        "//config/fieldparams:go_default_library",
        "//config/params:go_default_library",
+        "//consensus-types:go_default_library",
        "//consensus-types/blocks:go_default_library",
        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
--- a/beacon-chain/core/blocks/payload.go
+++ b/beacon-chain/core/blocks/payload.go
@@ -7,6 +7,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/time"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	consensus_types "github.com/prysmaticlabs/prysm/v4/consensus-types"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
@@ -60,7 +61,7 @@ func IsExecutionBlock(body interfaces.ReadOnlyBeaconBlockBody) (bool, error) {
 	}
 	payload, err := body.Execution()
 	switch {
-	case errors.Is(err, blocks.ErrUnsupportedGetter):
+	case errors.Is(err, consensus_types.ErrUnsupportedField):
 		return false, nil
 	case err != nil:
 		return false, err
--- a/beacon-chain/core/blocks/payload_test.go
+++ b/beacon-chain/core/blocks/payload_test.go
@@ -1,7 +1,6 @@
 package blocks_test

 import (
-	"math/big"
 	"testing"

 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
@@ -610,7 +609,7 @@ func Test_ProcessPayloadCapella(t *testing.T) {
 	random, err := helpers.RandaoMix(st, time.CurrentEpoch(st))
 	require.NoError(t, err)
 	payload.PrevRandao = random
-	wrapped, err := consensusblocks.WrappedExecutionPayloadCapella(payload, big.NewInt(0))
+	wrapped, err := consensusblocks.WrappedExecutionPayloadCapella(payload, 0)
 	require.NoError(t, err)
 	_, err = blocks.ProcessPayload(st, wrapped)
 	require.NoError(t, err)
@@ -874,7 +873,7 @@ func emptyPayloadHeaderCapella() (interfaces.ExecutionData, error) {
 		TransactionsRoot: make([]byte, fieldparams.RootLength),
 		WithdrawalsRoot:  make([]byte, fieldparams.RootLength),
 		ExtraData:        make([]byte, 0),
-	}, big.NewInt(0))
+	}, 0)
 }

 func emptyPayload() *enginev1.ExecutionPayload {
--- a/beacon-chain/core/blocks/withdrawals_test.go
+++ b/beacon-chain/core/blocks/withdrawals_test.go
@@ -1,7 +1,6 @@
 package blocks_test

 import (
-	"math/big"
 	"math/rand"
 	"testing"

@@ -644,7 +643,7 @@ func TestProcessBlindWithdrawals(t *testing.T) {
 			require.NoError(t, err)
 			wdRoot, err := ssz.WithdrawalSliceRoot(test.Args.Withdrawals, fieldparams.MaxWithdrawalsPerPayload)
 			require.NoError(t, err)
-			p, err := consensusblocks.WrappedExecutionPayloadHeaderCapella(&enginev1.ExecutionPayloadHeaderCapella{WithdrawalsRoot: wdRoot[:]}, big.NewInt(0))
+			p, err := consensusblocks.WrappedExecutionPayloadHeaderCapella(&enginev1.ExecutionPayloadHeaderCapella{WithdrawalsRoot: wdRoot[:]}, 0)
 			require.NoError(t, err)
 			post, err := blocks.ProcessWithdrawals(st, p)
 			if test.Control.ExpectedError {
@@ -1062,7 +1061,7 @@ func TestProcessWithdrawals(t *testing.T) {
 			}
 			st, err := prepareValidators(spb, test.Args)
 			require.NoError(t, err)
-			p, err := consensusblocks.WrappedExecutionPayloadCapella(&enginev1.ExecutionPayloadCapella{Withdrawals: test.Args.Withdrawals}, big.NewInt(0))
+			p, err := consensusblocks.WrappedExecutionPayloadCapella(&enginev1.ExecutionPayloadCapella{Withdrawals: test.Args.Withdrawals}, 0)
 			require.NoError(t, err)
 			post, err := blocks.ProcessWithdrawals(st, p)
 			if test.Control.ExpectedError {
--- a/beacon-chain/core/epoch/epoch_processing.go
+++ b/beacon-chain/core/epoch/epoch_processing.go
@@ -393,6 +393,7 @@ func ProcessHistoricalDataUpdate(state state.BeaconState) (state.BeaconState, er

 // ProcessParticipationRecordUpdates rotates current/previous epoch attestations during epoch processing.
 //
+// nolint:dupword
 // Spec pseudocode definition:
 //
 //	def process_participation_record_updates(state: BeaconState) -> None:
--- a/beacon-chain/core/epoch/precompute/reward_penalty.go
+++ b/beacon-chain/core/epoch/precompute/reward_penalty.go
@@ -14,7 +14,7 @@ type attesterRewardsFunc func(state.ReadOnlyBeaconState, *Balance, []*Validator)
 type proposerRewardsFunc func(state.ReadOnlyBeaconState, *Balance, []*Validator) ([]uint64, error)

 // ProcessRewardsAndPenaltiesPrecompute processes the rewards and penalties of individual validator.
-// This is an optimized version by passing in precomputed validator attesting records and and total epoch balances.
+// This is an optimized version by passing in precomputed validator attesting records and total epoch balances.
 func ProcessRewardsAndPenaltiesPrecompute(
 	state state.BeaconState,
 	pBal *Balance,
@@ -104,7 +104,6 @@ func attestationDelta(pBal *Balance, sqrtActiveCurrentEpoch uint64, v *Validator
 		} else {
 			rewardNumerator := br * (pBal.PrevEpochAttested / effectiveBalanceIncrement)
 			r += rewardNumerator / currentEpochBalance
-
 		}
 	} else {
 		p += br
--- a/beacon-chain/core/feed/state/events.go
+++ b/beacon-chain/core/feed/state/events.go
@@ -15,12 +15,11 @@ const (
 	BlockProcessed = iota + 1
 	// ChainStarted is sent when enough validators are active to start proposing blocks.
 	ChainStarted
-	// Initialized is sent when the internal beacon node's state is ready to be accessed.
-	Initialized
-	// Synced is sent when the beacon node has completed syncing and is ready to participate in the network.
-	Synced
-	// Reorg is an event sent when the new head state's slot after a block
-	// transition is lower than its previous head state slot value.
+	// deprecated: Initialized is sent when the internal beacon node's state is ready to be accessed.
+	_
+	// deprecated: Synced is sent when the beacon node has completed syncing and is ready to participate in the network.
+	_
+	// Reorg is an event sent when the new head is not a descendant of the previous head.
 	Reorg
 	// FinalizedCheckpoint event.
 	FinalizedCheckpoint
--- a/beacon-chain/core/helpers/BUILD.bazel
+++ b/beacon-chain/core/helpers/BUILD.bazel
@@ -38,6 +38,7 @@ go_library(
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
+        "@io_opencensus_go//trace:go_default_library",
    ],
 )

@@ -48,6 +49,7 @@ go_test(
        "attestation_test.go",
        "beacon_committee_test.go",
        "block_test.go",
+        "main_test.go",
        "randao_test.go",
        "rewards_penalties_test.go",
        "shuffle_test.go",
@@ -56,6 +58,7 @@ go_test(
        "weak_subjectivity_test.go",
    ],
    embed = [":go_default_library"],
+    race = "on",
    shard_count = 2,
    deps = [
        "//beacon-chain/cache:go_default_library",
@@ -66,7 +69,6 @@ go_test(
        "//config/params:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//container/slice:go_default_library",
-        "//crypto/bls:go_default_library",
        "//crypto/hash:go_default_library",
        "//encoding/bytesutil:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
--- a/beacon-chain/core/helpers/attestation.go
+++ b/beacon-chain/core/helpers/attestation.go
@@ -8,13 +8,16 @@ import (

 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v4/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v4/crypto/hash"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	prysmTime "github.com/prysmaticlabs/prysm/v4/time"
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 )

+var (
+	ErrTooLate = errors.New("attestation is too late")
+)
+
 // ValidateNilAttestation checks if any composite field of input attestation is nil.
 // Access to these nil fields will result in run time panic,
 // it is recommended to run these checks as first line of defense.
@@ -66,25 +69,6 @@ func IsAggregator(committeeCount uint64, slotSig []byte) (bool, error) {
 	return binary.LittleEndian.Uint64(b[:8])%modulo == 0, nil
 }

-// AggregateSignature returns the aggregated signature of the input attestations.
-//
-// Spec pseudocode definition:
-//
-//	def get_aggregate_signature(attestations: Sequence[Attestation]) -> BLSSignature:
-//	 signatures = [attestation.signature for attestation in attestations]
-//	 return bls.Aggregate(signatures)
-func AggregateSignature(attestations []*ethpb.Attestation) (bls.Signature, error) {
-	sigs := make([]bls.Signature, len(attestations))
-	var err error
-	for i := 0; i < len(sigs); i++ {
-		sigs[i], err = bls.SignatureFromBytes(attestations[i].Signature)
-		if err != nil {
-			return nil, err
-		}
-	}
-	return bls.AggregateSignatures(sigs), nil
-}
-
 // IsAggregated returns true if the attestation is an aggregated attestation,
 // false otherwise.
 func IsAggregated(attestation *ethpb.Attestation) bool {
@@ -183,11 +167,11 @@ func ValidateAttestationTime(attSlot primitives.Slot, genesisTime time.Time, clo
 		currentSlot,
 	)
 	if attTime.Before(lowerBounds) {
-		attReceivedTooEarlyCount.Inc()
-		return attError
+		attReceivedTooLateCount.Inc()
+		return errors.Join(ErrTooLate, attError)
 	}
 	if attTime.After(upperBounds) {
-		attReceivedTooLateCount.Inc()
+		attReceivedTooEarlyCount.Inc()
 		return attError
 	}
 	return nil
--- a/beacon-chain/core/helpers/attestation_test.go
+++ b/beacon-chain/core/helpers/attestation_test.go
@@ -10,8 +10,6 @@ import (
 	state_native "github.com/prysmaticlabs/prysm/v4/beacon-chain/state/state-native"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v4/crypto/bls"
-	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v4/testing/assert"
 	"github.com/prysmaticlabs/prysm/v4/testing/require"
@@ -45,44 +43,6 @@ func TestAttestation_IsAggregator(t *testing.T) {
 	})
 }

-func TestAttestation_AggregateSignature(t *testing.T) {
-	t.Run("verified", func(t *testing.T) {
-		pubkeys := make([]bls.PublicKey, 0, 100)
-		atts := make([]*ethpb.Attestation, 0, 100)
-		msg := bytesutil.ToBytes32([]byte("hello"))
-		for i := 0; i < 100; i++ {
-			priv, err := bls.RandKey()
-			require.NoError(t, err)
-			pub := priv.PublicKey()
-			sig := priv.Sign(msg[:])
-			pubkeys = append(pubkeys, pub)
-			att := &ethpb.Attestation{Signature: sig.Marshal()}
-			atts = append(atts, att)
-		}
-		aggSig, err := helpers.AggregateSignature(atts)
-		require.NoError(t, err)
-		assert.Equal(t, true, aggSig.FastAggregateVerify(pubkeys, msg), "Signature did not verify")
-	})
-
-	t.Run("not verified", func(t *testing.T) {
-		pubkeys := make([]bls.PublicKey, 0, 100)
-		atts := make([]*ethpb.Attestation, 0, 100)
-		msg := []byte("hello")
-		for i := 0; i < 100; i++ {
-			priv, err := bls.RandKey()
-			require.NoError(t, err)
-			pub := priv.PublicKey()
-			sig := priv.Sign(msg)
-			pubkeys = append(pubkeys, pub)
-			att := &ethpb.Attestation{Signature: sig.Marshal()}
-			atts = append(atts, att)
-		}
-		aggSig, err := helpers.AggregateSignature(atts[0 : len(atts)-2])
-		require.NoError(t, err)
-		assert.Equal(t, false, aggSig.FastAggregateVerify(pubkeys, bytesutil.ToBytes32(msg)), "Signature not suppose to verify")
-	})
-}
-
 func TestAttestation_ComputeSubnetForAttestation(t *testing.T) {
 	// Create 10 committees
 	committeeCount := uint64(10)
--- a/beacon-chain/core/helpers/beacon_committee.go
+++ b/beacon-chain/core/helpers/beacon_committee.go
@@ -336,20 +336,21 @@ func UpdateCommitteeCache(ctx context.Context, state state.ReadOnlyBeaconState,
 }

 // UpdateProposerIndicesInCache updates proposer indices entry of the committee cache.
-func UpdateProposerIndicesInCache(ctx context.Context, state state.ReadOnlyBeaconState) error {
+// Input state is used to retrieve active validator indices.
+// Input epoch is the epoch to retrieve proposer indices for.
+func UpdateProposerIndicesInCache(ctx context.Context, state state.ReadOnlyBeaconState, epoch primitives.Epoch) error {
 	// The cache uses the state root at the (current epoch - 1)'s slot as key. (e.g. for epoch 2, the key is root at slot 63)
 	// Which is the reason why we skip genesis epoch.
-	if time.CurrentEpoch(state) <= params.BeaconConfig().GenesisEpoch+params.BeaconConfig().MinSeedLookahead {
+	if epoch <= params.BeaconConfig().GenesisEpoch+params.BeaconConfig().MinSeedLookahead {
 		return nil
 	}

 	// Use state root from (current_epoch - 1))
-	wantedEpoch := time.PrevEpoch(state)
-	s, err := slots.EpochEnd(wantedEpoch)
+	s, err := slots.EpochEnd(epoch - 1)
 	if err != nil {
 		return err
 	}
-	r, err := StateRootAtSlot(state, s)
+	r, err := state.StateRootAtIndex(uint64(s % params.BeaconConfig().SlotsPerHistoricalRoot))
 	if err != nil {
 		return err
 	}
@@ -366,11 +367,11 @@ func UpdateProposerIndicesInCache(ctx context.Context, state state.ReadOnlyBeaco
 		return nil
 	}

-	indices, err := ActiveValidatorIndices(ctx, state, time.CurrentEpoch(state))
+	indices, err := ActiveValidatorIndices(ctx, state, epoch)
 	if err != nil {
 		return err
 	}
-	proposerIndices, err := precomputeProposerIndices(state, indices)
+	proposerIndices, err := precomputeProposerIndices(state, indices, epoch)
 	if err != nil {
 		return err
 	}
@@ -382,10 +383,10 @@ func UpdateProposerIndicesInCache(ctx context.Context, state state.ReadOnlyBeaco

 // ClearCache clears the beacon committee cache and sync committee cache.
 func ClearCache() {
-	committeeCache = cache.NewCommitteesCache()
-	proposerIndicesCache = cache.NewProposerIndicesCache()
-	syncCommitteeCache = cache.NewSyncCommittee()
-	balanceCache = cache.NewEffectiveBalanceCache()
+	committeeCache.Clear()
+	proposerIndicesCache.Clear()
+	syncCommitteeCache.Clear()
+	balanceCache.Clear()
 }

 // computeCommittee returns the requested shuffled committee out of the total committees using
@@ -432,11 +433,10 @@ func computeCommittee(

 // This computes proposer indices of the current epoch and returns a list of proposer indices,
 // the index of the list represents the slot number.
-func precomputeProposerIndices(state state.ReadOnlyBeaconState, activeIndices []primitives.ValidatorIndex) ([]primitives.ValidatorIndex, error) {
+func precomputeProposerIndices(state state.ReadOnlyBeaconState, activeIndices []primitives.ValidatorIndex, e primitives.Epoch) ([]primitives.ValidatorIndex, error) {
 	hashFunc := hash.CustomSHA256Hasher()
 	proposerIndices := make([]primitives.ValidatorIndex, params.BeaconConfig().SlotsPerEpoch)

-	e := time.CurrentEpoch(state)
 	seed, err := Seed(state, e, params.BeaconConfig().DomainBeaconProposer)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not generate seed")
--- a/beacon-chain/core/helpers/beacon_committee_test.go
+++ b/beacon-chain/core/helpers/beacon_committee_test.go
@@ -91,6 +91,7 @@ func TestVerifyBitfieldLength_OK(t *testing.T) {

 func TestCommitteeAssignments_CannotRetrieveFutureEpoch(t *testing.T) {
 	ClearCache()
+	defer ClearCache()
 	epoch := primitives.Epoch(1)
 	state, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
 		Slot: 0, // Epoch 0.
@@ -101,6 +102,8 @@ func TestCommitteeAssignments_CannotRetrieveFutureEpoch(t *testing.T) {
 }

 func TestCommitteeAssignments_NoProposerForSlot0(t *testing.T) {
+	ClearCache()
+	defer ClearCache()
 	validators := make([]*ethpb.Validator, 4*params.BeaconConfig().SlotsPerEpoch)
 	for i := 0; i < len(validators); i++ {
 		var activationEpoch primitives.Epoch
@@ -118,7 +121,6 @@ func TestCommitteeAssignments_NoProposerForSlot0(t *testing.T) {
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
 	require.NoError(t, err)
-	ClearCache()
 	_, proposerIndexToSlots, err := CommitteeAssignments(context.Background(), state, 0)
 	require.NoError(t, err, "Failed to determine CommitteeAssignments")
 	for _, ss := range proposerIndexToSlots {
@@ -188,6 +190,7 @@ func TestCommitteeAssignments_CanRetrieve(t *testing.T) {
 		},
 	}

+	defer ClearCache()
 	for i, tt := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
 			ClearCache()
@@ -255,6 +258,8 @@ func TestCommitteeAssignments_CannotRetrieveOlderThanSlotsPerHistoricalRoot(t *t
 }

 func TestCommitteeAssignments_EverySlotHasMin1Proposer(t *testing.T) {
+	ClearCache()
+	defer ClearCache()
 	// Initialize test with 256 validators, each slot and each index gets 4 validators.
 	validators := make([]*ethpb.Validator, 4*params.BeaconConfig().SlotsPerEpoch)
 	for i := 0; i < len(validators); i++ {
@@ -269,7 +274,6 @@ func TestCommitteeAssignments_EverySlotHasMin1Proposer(t *testing.T) {
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	})
 	require.NoError(t, err)
-	ClearCache()
 	epoch := primitives.Epoch(1)
 	_, proposerIndexToSlots, err := CommitteeAssignments(context.Background(), state, epoch)
 	require.NoError(t, err, "Failed to determine CommitteeAssignments")
@@ -376,6 +380,7 @@ func TestVerifyAttestationBitfieldLengths_OK(t *testing.T) {
 		},
 	}

+	defer ClearCache()
 	for i, tt := range tests {
 		ClearCache()
 		require.NoError(t, state.SetSlot(tt.stateSlot))
@@ -390,6 +395,7 @@ func TestVerifyAttestationBitfieldLengths_OK(t *testing.T) {

 func TestUpdateCommitteeCache_CanUpdate(t *testing.T) {
 	ClearCache()
+	defer ClearCache()
 	validatorCount := params.BeaconConfig().MinGenesisActiveValidatorCount
 	validators := make([]*ethpb.Validator, validatorCount)
 	indices := make([]primitives.ValidatorIndex, validatorCount)
@@ -633,7 +639,7 @@ func TestPrecomputeProposerIndices_Ok(t *testing.T) {
 	indices, err := ActiveValidatorIndices(context.Background(), state, 0)
 	require.NoError(t, err)

-	proposerIndices, err := precomputeProposerIndices(state, indices)
+	proposerIndices, err := precomputeProposerIndices(state, indices, time.CurrentEpoch(state))
 	require.NoError(t, err)

 	var wantedProposerIndices []primitives.ValidatorIndex
--- a/beacon-chain/core/helpers/main_test.go
+++ b/beacon-chain/core/helpers/main_test.go
@@ -0,0 +1,13 @@
+package helpers
+
+import (
+	"os"
+	"testing"
+)
+
+// run ClearCache before each test to prevent cross-test side effects
+func TestMain(m *testing.M) {
+	ClearCache()
+	code := m.Run()
+	os.Exit(code)
+}
--- a/beacon-chain/core/helpers/rewards_penalties_test.go
+++ b/beacon-chain/core/helpers/rewards_penalties_test.go
@@ -75,6 +75,8 @@ func TestTotalActiveBalance(t *testing.T) {
 }

 func TestTotalActiveBal_ReturnMin(t *testing.T) {
+	ClearCache()
+	defer ClearCache()
 	tests := []struct {
 		vCount int
 	}{
@@ -96,6 +98,8 @@ func TestTotalActiveBal_ReturnMin(t *testing.T) {
 }

 func TestTotalActiveBalance_WithCache(t *testing.T) {
+	ClearCache()
+	defer ClearCache()
 	tests := []struct {
 		vCount    int
 		wantCount int
--- a/Show More
+++ b/Show More
@@ -1 +1 @@
 .1.0
 .2.1