Merge branch 'develop' into revert-12704-proposer-verify-attestation

Holesky support (#12821 )
* Add holesky config Copy config/params from deneb-integration * Add --holesky flag * Handle no genesis block error and suggest to user a workaround
2026-01-10 05:47:59 -05:00 · 2023-08-29 10:15:05 -07:00 · 2023-08-29 14:27:50 +00:00 · 2023-08-29 13:24:54 +00:00 · 2023-08-28 09:28:20 -07:00 · 2023-08-25 21:14:08 +00:00
516 changed files with 27583 additions and 13512 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
+6.3.2
--- a/.github/workflows/fuzz.yml
+++ b/.github/workflows/fuzz.yml
@@ -0,0 +1,42 @@
+name: "fuzz"
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "0 12 * * *"
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  list:
+    runs-on: ubuntu-latest
+    timeout-minutes: 180
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v4
+        with:
+          go-version: '1.20'
+      - id: list
+        uses: shogo82148/actions-go-fuzz/list@v0
+    outputs:
+      fuzz-tests: ${{steps.list.outputs.fuzz-tests}}
+
+  fuzz:
+    runs-on: ubuntu-latest
+    timeout-minutes: 360
+    needs: list
+    strategy:
+      fail-fast: false
+      matrix:
+        include: ${{fromJson(needs.list.outputs.fuzz-tests)}}
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v4
+        with:
+          go-version: '1.20'
+      - uses: shogo82148/actions-go-fuzz/run@v0
+        with:
+          packages: ${{ matrix.package }}
+          fuzz-regexp: ${{ matrix.func }}
+          fuzz-time: "20m"
--- 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"
@@ -134,8 +133,8 @@ nogo(
        # nogo checks that fail with coverage enabled.
        ":coverage_enabled": [],
        "//conditions:default": [
-            "@org_golang_x_tools//go/analysis/passes/lostcancel:go_default_library",
            "@org_golang_x_tools//go/analysis/passes/composite:go_default_library",
+            "@org_golang_x_tools//go/analysis/passes/lostcancel:go_default_library",
        ],
    }),
 )
--- 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/109
+++ b/109
@@ -17,26 +17,34 @@ load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")
 rules_pkg_dependencies()

 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 = "973ab22945b921ef45b8e1d6ce01ca7ce1b8a462167449a36e297438c4ec2755",
+    strip_prefix = "hermetic_cc_toolchain-5098046bccc15d2962f3cc8e7e53d6a2a26072dc",
+    urls = [
+        "https://github.com/uber/hermetic_cc_toolchain/archive/5098046bccc15d2962f3cc8e7e53d6a2a26072dc.tar.gz",  # 2023-06-28
+    ],
 )

-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")

@@ -59,10 +67,10 @@ bazel_skylib_workspace()

 http_archive(
    name = "bazel_gazelle",
-    sha256 = "5982e5463f171da99e3bdaeff8c0f48283a7a5f396ec5282910b9e8a49c0dd7e",
+    sha256 = "29d5dafc2a5582995488c6735115d1d366fcd6a0fc2e2a153f02988706349825",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.25.0/bazel-gazelle-v0.25.0.tar.gz",
-        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.25.0/bazel-gazelle-v0.25.0.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.31.0/bazel-gazelle-v0.31.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.31.0/bazel-gazelle-v0.31.0.tar.gz",
    ],
 )

@@ -86,10 +94,10 @@ http_archive(
        # Expose internals of go_test for custom build transitions.
        "//third_party:io_bazel_rules_go_test.patch",
    ],
-    sha256 = "6b65cb7917b4d1709f9410ffe00ecf3e160edf674b78c54a894471320862184f",
+    sha256 = "bfc5ce70b9d1634ae54f4e7b495657a18a04e0d596785f672d35d5f505ab491a",
    urls = [
-        "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",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.40.0/rules_go-v0.40.0.zip",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.40.0/rules_go-v0.40.0.zip",
    ],
 )

@@ -164,7 +172,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()

 go_register_toolchains(
-    go_version = "1.20.3",
+    go_version = "1.20.7",
    nogo = "@//:nogo",
 )

@@ -205,7 +213,7 @@ filegroup(
    url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )

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

 bls_test_version = "v0.1.1"

@@ -221,7 +229,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "1c806e04ac5e3779032c06a6009350b3836b6809bb23812993d6ececd7047cf5",
+    sha256 = "1118a663be4a00ba00f0635eb20287157f2b2f993aed64335bfbcd04af424c2b",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )

@@ -237,7 +245,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "2b42796dc5ccd9f1246032d0c17663e20f70334ff7e00325f0fc3af28cb24186",
+    sha256 = "acde6e10940d14f22277eda5b55b65a24623ac88e4c7a2e34134a6069f5eea82",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )

@@ -253,7 +261,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "231e3371e81ce9acde65d2910ec4580587e74dbbcfcbd9c675e473e022deec8a",
+    sha256 = "49c022f3a3478cea849ba8f877a9f7e4c1ded549edddc09993550bbc5bb192e1",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )

@@ -268,7 +276,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "219b74d95664ea7e8dfbf31162dfa206b9c0cf45919ea86db5fa0f8902977e3c",
+    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,
 )
@@ -305,39 +313,34 @@ filegroup(
 )

 http_archive(
-    name = "com_github_bazelbuild_buildtools",
-    sha256 = "7a182df18df1debabd9e36ae07c8edfa1378b8424a04561b674d933b965372b3",
-    strip_prefix = "buildtools-f2aed9ee205d62d45c55cfabbfd26342f8526862",
-    url = "https://github.com/bazelbuild/buildtools/archive/f2aed9ee205d62d45c55cfabbfd26342f8526862.zip",
+    name = "holesky_testnet",
+    build_file_content = """
+filegroup(
+    name = "configs",
+    srcs = [
+        "custom_config_data/config.yaml",
+    ],
+    visibility = ["//visibility:public"],
+)
+""",
+    sha256 = "4116c8acb54eb3ca28cc4dc9bc688e08e25da91d70ed1f2622f02d3c33eba922",
+    strip_prefix = "holesky-76057d57ab1f585519ecb606a9e5f7780e925a37",
+    url = "https://github.com/eth-clients/holesky/archive/76057d57ab1f585519ecb606a9e5f7780e925a37.tar.gz",  # Aug 27, 2023
 )

-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
 all_content = """filegroup(name = "all", srcs = glob(["**"]), visibility = ["//visibility:public"])"""

 # External dependencies
-
-http_archive(
-    name = "prysm_web_ui",
-    build_file_content = """
-filegroup(
-    name = "site",
-    srcs = glob(["**/*"]),
-    visibility = ["//visibility:public"],
-)
-""",
-    sha256 = "5006614c33e358699b4e072c649cd4c3866f7d41a691449d5156f6c6e07a4c60",
-    urls = [
-        "https://github.com/prysmaticlabs/prysm-web-ui/releases/download/v2.0.3/prysm-web-ui.tar.gz",
-    ],
-)
-
 load("//:deps.bzl", "prysm_deps")

 # gazelle:repository_macro deps.bzl%prysm_deps
@@ -369,10 +372,6 @@ load(

 _cc_image_repos()

-load("@io_bazel_rules_go//extras:embed_data_deps.bzl", "go_embed_data_dependencies")
-
-go_embed_data_dependencies()
-
 load("@com_github_atlassian_bazel_tools//gometalinter:deps.bzl", "gometalinter_dependencies")

 gometalinter_dependencies()
@@ -381,10 +380,6 @@ load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies")

 gazelle_dependencies()

-load("@com_github_bazelbuild_buildtools//buildifier:deps.bzl", "buildifier_dependencies")
-
-buildifier_dependencies()
-
 load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")

 protobuf_deps()
--- a/api/BUILD.bazel
+++ b/api/BUILD.bazel
@@ -0,0 +1,8 @@
+load("@prysm//tools/go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["headers.go"],
+    importpath = "github.com/prysmaticlabs/prysm/v4/api",
+    visibility = ["//visibility:public"],
+)
--- 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
@@ -5,11 +5,14 @@ import (
 	"fmt"
 	"path"

+	"github.com/ethereum/go-ethereum/common/hexutil"
 	"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 +21,8 @@ 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 +79,40 @@ 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", hexutil.Encode(sr[:])).
+		WithField("block_root", hexutil.Encode(br[:])).
+		Info("Downloaded checkpoint sync state and block.")
 	return &OriginData{
 		st: s,
 		b:  b,
@@ -140,7 +148,7 @@ 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/bid.go
+++ b/api/client/builder/bid.go
@@ -3,7 +3,6 @@ package builder
 import (
 	"math/big"

-	"github.com/pkg/errors"
 	ssz "github.com/prysmaticlabs/fastssz"
 	consensus_types "github.com/prysmaticlabs/prysm/v4/consensus-types"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
@@ -162,9 +161,6 @@ func WrappedBuilderBidCapella(p *ethpb.BuilderBidCapella) (Bid, error) {

 // Header returns the execution data interface.
 func (b builderBidCapella) Header() (interfaces.ExecutionData, error) {
-	if b.p == nil {
-		return nil, errors.New("builder bid is nil")
-	}
 	// We have to convert big endian to little endian because the value is coming from the execution layer.
 	v := big.NewInt(0).SetBytes(bytesutil.ReverseByteOrder(b.p.Value))
 	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header, math.WeiToGwei(v))
--- a/api/client/builder/client.go
+++ b/api/client/builder/client.go
@@ -11,7 +11,6 @@ import (
 	"net/url"
 	"strings"
 	"text/template"
-	"time"

 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
@@ -36,7 +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)
@@ -292,8 +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))
 		}
@@ -325,8 +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))
 		}
--- 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"`
@@ -319,29 +343,31 @@ 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
 }
@@ -355,22 +381,22 @@ func FromProto(payload *v1.ExecutionPayload) (ExecutionPayload, error) {
 	}
 	txs := make([]hexutil.Bytes, len(payload.Transactions))
 	for i := range payload.Transactions {
-		txs[i] = payload.Transactions[i]
+		txs[i] = bytesutil.SafeCopyBytes(payload.Transactions[i])
 	}
 	return ExecutionPayload{
-		ParentHash:    payload.ParentHash,
-		FeeRecipient:  payload.FeeRecipient,
-		StateRoot:     payload.StateRoot,
-		ReceiptsRoot:  payload.ReceiptsRoot,
-		LogsBloom:     payload.LogsBloom,
-		PrevRandao:    payload.PrevRandao,
+		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:     payload.ExtraData,
+		ExtraData:     bytesutil.SafeCopyBytes(payload.ExtraData),
 		BaseFeePerGas: bFee,
-		BlockHash:     payload.BlockHash,
+		BlockHash:     bytesutil.SafeCopyBytes(payload.BlockHash),
 		Transactions:  txs,
 	}, nil
 }
@@ -384,36 +410,37 @@ func FromProtoCapella(payload *v1.ExecutionPayloadCapella) (ExecutionPayloadCape
 	}
 	txs := make([]hexutil.Bytes, len(payload.Transactions))
 	for i := range payload.Transactions {
-		txs[i] = payload.Transactions[i]
+		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:        w.Address,
+			Address:        bytesutil.SafeCopyBytes(w.Address),
 			Amount:         Uint256{Int: big.NewInt(0).SetUint64(w.Amount)},
 		}
 	}
 	return ExecutionPayloadCapella{
-		ParentHash:    payload.ParentHash,
-		FeeRecipient:  payload.FeeRecipient,
-		StateRoot:     payload.StateRoot,
-		ReceiptsRoot:  payload.ReceiptsRoot,
-		LogsBloom:     payload.LogsBloom,
-		PrevRandao:    payload.PrevRandao,
+		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:     payload.ExtraData,
+		ExtraData:     bytesutil.SafeCopyBytes(payload.ExtraData),
 		BaseFeePerGas: bFee,
-		BlockHash:     payload.BlockHash,
+		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"`
@@ -421,6 +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 {
@@ -428,10 +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 {
@@ -439,37 +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"`
@@ -489,6 +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)
@@ -514,6 +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{}
@@ -527,11 +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"`
@@ -550,43 +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"`
@@ -594,18 +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"`
@@ -616,6 +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"`
@@ -632,10 +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"`
@@ -646,10 +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"`
@@ -660,10 +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"`
@@ -680,10 +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 {
@@ -700,10 +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"`
@@ -714,10 +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"`
@@ -728,10 +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"`
@@ -748,10 +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"`
@@ -764,10 +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"`
@@ -782,10 +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 {
@@ -800,10 +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"`
@@ -814,10 +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"`
@@ -828,10 +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"`
@@ -842,10 +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"`
@@ -858,6 +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 {
@@ -904,10 +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"`
@@ -918,10 +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"`
@@ -934,18 +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"`
@@ -956,6 +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"`
@@ -972,6 +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 {
@@ -1024,6 +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/api/gateway/apimiddleware/BUILD.bazel
+++ b/api/gateway/apimiddleware/BUILD.bazel
@@ -13,6 +13,7 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/v4/api/gateway/apimiddleware",
    visibility = ["//visibility:public"],
    deps = [
+        "//api:go_default_library",
        "//api/grpc:go_default_library",
        "//encoding/bytesutil:go_default_library",
        "@com_github_ethereum_go_ethereum//common:go_default_library",
@@ -32,6 +33,7 @@ go_test(
    ],
    embed = [":go_default_library"],
    deps = [
+        "//api:go_default_library",
        "//api/grpc:go_default_library",
        "//testing/assert:go_default_library",
        "//testing/require:go_default_library",
--- a/api/gateway/apimiddleware/process_request.go
+++ b/api/gateway/apimiddleware/process_request.go
@@ -10,6 +10,7 @@ import (
 	"strings"

 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v4/api"
 	"github.com/prysmaticlabs/prysm/v4/api/grpc"
 )

@@ -116,7 +117,11 @@ func HandleGrpcResponseError(errJson ErrorJson, resp *http.Response, respBody []
 		// Something went wrong, but the request completed, meaning we can write headers and the error message.
 		for h, vs := range resp.Header {
 			for _, v := range vs {
-				w.Header().Set(h, v)
+				if strings.HasSuffix(h, api.VersionHeader) {
+					w.Header().Set(api.VersionHeader, v)
+				} else {
+					w.Header().Set(h, v)
+				}
 			}
 		}
 		// Handle gRPC timeout.
@@ -187,9 +192,11 @@ func WriteMiddlewareResponseHeadersAndBody(grpcResp *http.Response, responseJson
 	var statusCodeHeader string
 	for h, vs := range grpcResp.Header {
 		// We don't want to expose any gRPC metadata in the HTTP response, so we skip forwarding metadata headers.
-		if strings.HasPrefix(h, "Grpc-Metadata") {
-			if h == "Grpc-Metadata-"+grpc.HttpCodeMetadataKey {
+		if strings.HasPrefix(h, grpc.MetadataPrefix) {
+			if h == grpc.WithPrefix(grpc.HttpCodeMetadataKey) {
 				statusCodeHeader = vs[0]
+			} else if strings.HasSuffix(h, api.VersionHeader) {
+				w.Header().Set(api.VersionHeader, vs[0])
 			}
 		} else {
 			for _, v := range vs {
@@ -223,7 +230,7 @@ func WriteError(w http.ResponseWriter, errJson ErrorJson, responseHeader http.He
 	// Include custom error in the error JSON.
 	hasCustomError := false
 	if responseHeader != nil {
-		customError, ok := responseHeader["Grpc-Metadata-"+grpc.CustomErrorMetadataKey]
+		customError, ok := responseHeader[grpc.WithPrefix(grpc.CustomErrorMetadataKey)]
 		if ok {
 			hasCustomError = true
 			// Assume header has only one value and read the 0 index.
--- a/api/gateway/apimiddleware/process_request_test.go
+++ b/api/gateway/apimiddleware/process_request_test.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 	"testing"

+	"github.com/prysmaticlabs/prysm/v4/api"
 	"github.com/prysmaticlabs/prysm/v4/api/grpc"
 	"github.com/prysmaticlabs/prysm/v4/testing/assert"
 	"github.com/prysmaticlabs/prysm/v4/testing/require"
@@ -280,7 +281,8 @@ func TestWriteMiddlewareResponseHeadersAndBody(t *testing.T) {
 		response := &http.Response{
 			Header: http.Header{
 				"Foo": []string{"foo"},
-				"Grpc-Metadata-" + grpc.HttpCodeMetadataKey: []string{"204"},
+				grpc.WithPrefix(grpc.HttpCodeMetadataKey): []string{"204"},
+				grpc.WithPrefix(api.VersionHeader):        []string{"capella"},
 			},
 		}
 		container := defaultResponseContainer()
@@ -299,6 +301,9 @@ func TestWriteMiddlewareResponseHeadersAndBody(t *testing.T) {
 		require.Equal(t, true, ok, "header not found")
 		require.Equal(t, 1, len(v), "wrong number of header values")
 		assert.Equal(t, "224", v[0])
+		v, ok = writer.Header()["Eth-Consensus-Version"]
+		require.Equal(t, true, ok, "header not found")
+		assert.Equal(t, "capella", v[0])
 		assert.Equal(t, 204, writer.Code)
 		assert.DeepEqual(t, responseJson, writer.Body.Bytes())
 	})
@@ -320,11 +325,12 @@ func TestWriteMiddlewareResponseHeadersAndBody(t *testing.T) {

 	t.Run("GET_invalid_status_code", func(t *testing.T) {
 		response := &http.Response{
-			Header: http.Header{},
+			Header: http.Header{"Grpc-Metadata-Eth-Consensus-Version": []string{"capella"}},
 		}

 		// Set invalid status code.
-		response.Header["Grpc-Metadata-"+grpc.HttpCodeMetadataKey] = []string{"invalid"}
+		response.Header[grpc.WithPrefix(grpc.HttpCodeMetadataKey)] = []string{"invalid"}
+		response.Header[grpc.WithPrefix(api.VersionHeader)] = []string{"capella"}

 		container := defaultResponseContainer()
 		responseJson, err := json.Marshal(container)
@@ -390,7 +396,7 @@ func TestWriteMiddlewareResponseHeadersAndBody(t *testing.T) {
 func TestWriteError(t *testing.T) {
 	t.Run("ok", func(t *testing.T) {
 		responseHeader := http.Header{
-			"Grpc-Metadata-" + grpc.CustomErrorMetadataKey: []string{"{\"CustomField\":\"bar\"}"},
+			grpc.WithPrefix(grpc.CustomErrorMetadataKey): []string{"{\"CustomField\":\"bar\"}"},
 		}
 		errJson := &testErrorJson{
 			Message: "foo",
@@ -420,7 +426,7 @@ func TestWriteError(t *testing.T) {
 		logHook := test.NewGlobal()

 		responseHeader := http.Header{
-			"Grpc-Metadata-" + grpc.CustomErrorMetadataKey: []string{"invalid"},
+			grpc.WithPrefix(grpc.CustomErrorMetadataKey): []string{"invalid"},
 		}

 		WriteError(httptest.NewRecorder(), &testErrorJson{}, responseHeader)
--- a/api/grpc/parameters.go
+++ b/api/grpc/parameters.go
@@ -6,3 +6,11 @@ const CustomErrorMetadataKey = "Custom-Error"

 // HttpCodeMetadataKey is the key to use when setting custom HTTP status codes in gRPC metadata.
 const HttpCodeMetadataKey = "X-Http-Code"
+
+// MetadataPrefix is the prefix for grpc headers on metadata
+const MetadataPrefix = "Grpc-Metadata"
+
+// WithPrefix creates a new string with grpc metadata prefix
+func WithPrefix(value string) string {
+	return MetadataPrefix + "-" + value
+}
--- a/api/headers.go
+++ b/api/headers.go
@@ -0,0 +1,7 @@
+package api
+
+const (
+	VersionHeader        = "Eth-Consensus-Version"
+	JsonMediaType        = "application/json"
+	OctetStreamMediaType = "application/octet-stream"
+)
--- 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/beacon-chain/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -88,6 +88,7 @@ go_library(
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
+        "@org_golang_x_sync//errgroup:go_default_library",
    ],
 )

--- a/beacon-chain/blockchain/chain_info.go
+++ b/beacon-chain/blockchain/chain_info.go
@@ -340,7 +340,13 @@ func (s *Service) IsOptimistic(_ context.Context) (bool, error) {
 	}
 	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()
@@ -381,7 +387,7 @@ 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
+// IsViableForCheckpoint 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()
@@ -493,6 +499,13 @@ func (s *Service) Ancestor(ctx context.Context, root []byte, slot primitives.Slo
 	return ar[:], nil
 }

+// SetOptimisticToInvalid wraps the corresponding method in forkchoice
+func (s *Service) SetOptimisticToInvalid(ctx context.Context, root, parent, lvh [32]byte) ([][32]byte, error) {
+	s.cfg.ForkChoiceStore.Lock()
+	defer s.cfg.ForkChoiceStore.Unlock()
+	return s.cfg.ForkChoiceStore.SetOptimisticToInvalid(ctx, root, parent, lvh)
+}
+
 // SetGenesisTime sets the genesis time of beacon chain.
 func (s *Service) SetGenesisTime(t time.Time) {
 	s.genesisTime = t
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -422,6 +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
@@ -41,13 +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.
@@ -55,6 +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
@@ -72,6 +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
@@ -154,7 +154,7 @@ 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(),
@@ -182,21 +182,24 @@ func (s *Service) getPayloadHash(ctx context.Context, root []byte) ([32]byte, er

 // notifyNewPayload signals execution engine on a new payload.
 // It returns true if the EL has returned VALID for the block
-func (s *Service) notifyNewPayload(ctx context.Context, postStateVersion int,
-	postStateHeader interfaces.ExecutionData, blk interfaces.ReadOnlySignedBeaconBlock) (bool, error) {
+func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int,
+	preStateHeader interfaces.ExecutionData, blk interfaces.ReadOnlySignedBeaconBlock) (bool, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.notifyNewPayload")
 	defer span.End()

 	// Execution payload is only supported in Bellatrix and beyond. Pre
 	// merge blocks are never optimistic
-	if blocks.IsPreBellatrixVersion(postStateVersion) {
+	if blk == nil {
+		return false, errors.New("signed beacon block can't be nil")
+	}
+	if preStateVersion < version.Bellatrix {
 		return true, nil
 	}
 	if err := consensusblocks.BeaconBlockIsNil(blk); err != nil {
 		return false, err
 	}
 	body := blk.Block().Body()
-	enabled, err := blocks.IsExecutionEnabledUsingHeader(postStateHeader, body)
+	enabled, err := blocks.IsExecutionEnabledUsingHeader(preStateHeader, body)
 	if err != nil {
 		return false, errors.Wrap(invalidBlock{error: err}, "could not determine if execution is enabled")
 	}
@@ -220,35 +223,37 @@ 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) pruneInvalidBlock(ctx context.Context, root, parentRoot, lvh [32]byte) error {
+	newPayloadInvalidNodeCount.Inc()
+	invalidRoots, err := s.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, headRoot []byte) (bool, payloadattribute.Attributer, primitives.ValidatorIndex) {
--- a/beacon-chain/blockchain/execution_engine_test.go
+++ b/beacon-chain/blockchain/execution_engine_test.go
@@ -525,11 +525,13 @@ func Test_NotifyNewPayload(t *testing.T) {
 		{
 			name:           "phase 0 post state",
 			postState:      phase0State,
+			blk:            altairBlk, // same as phase 0 for this test
 			isValidPayload: true,
 		},
 		{
 			name:           "altair post state",
 			postState:      altairState,
+			blk:            altairBlk,
 			isValidPayload: true,
 		},
 		{
@@ -743,6 +745,37 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	require.Equal(t, true, validated)
 }

+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.pruneInvalidBlock(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
--- a/beacon-chain/blockchain/head.go
+++ b/beacon-chain/blockchain/head.go
@@ -47,9 +47,11 @@ 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
@@ -94,6 +96,10 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 		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)
@@ -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")
 	}

@@ -173,7 +182,7 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 // This gets called to update canonical root mapping. It does not save head block
 // root in DB. With the inception of initial-sync-cache-state flag, it uses finalized
 // check point as anchors to resume sync therefore head is no longer needed to be saved on per slot basis.
-func (s *Service) saveHeadNoDB(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock, r [32]byte, hs state.BeaconState) error {
+func (s *Service) saveHeadNoDB(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock, r [32]byte, hs state.BeaconState, optimistic bool) error {
 	if err := blocks.BeaconBlockIsNil(b); err != nil {
 		return err
 	}
@@ -189,26 +198,28 @@ func (s *Service) saveHeadNoDB(ctx context.Context, b interfaces.ReadOnlySignedB
 	if err != nil {
 		return err
 	}
-	if err := s.setHeadInitialSync(r, bCp, hs); err != nil {
+	if err := s.setHeadInitialSync(r, bCp, hs, optimistic); err != nil {
 		return errors.Wrap(err, "could not set head")
 	}
 	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
 }
@@ -216,7 +227,7 @@ func (s *Service) setHead(root [32]byte, block interfaces.ReadOnlySignedBeaconBl
 // This sets head view object which is used to track the head slot, root, block and state. The method
 // assumes that state being passed into the method will not be modified by any other alternate
 // caller which holds the state's reference.
-func (s *Service) setHeadInitialSync(root [32]byte, block interfaces.ReadOnlySignedBeaconBlock, state state.BeaconState) error {
+func (s *Service) setHeadInitialSync(root [32]byte, block interfaces.ReadOnlySignedBeaconBlock, state state.BeaconState, optimistic bool) error {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -226,9 +237,10 @@ func (s *Service) setHeadInitialSync(root [32]byte, block interfaces.ReadOnlySig
 		return err
 	}
 	s.head = &head{
-		root:  root,
-		block: bCp,
-		state: state,
+		root:       root,
+		block:      bCp,
+		state:      state,
+		optimistic: optimistic,
 	}
 	return nil
 }
--- a/beacon-chain/blockchain/head_sync_committee_info.go
+++ b/beacon-chain/blockchain/head_sync_committee_info.go
@@ -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/log.go
+++ b/beacon-chain/blockchain/log.go
@@ -53,7 +53,7 @@ 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, consensus_types.ErrUnsupportedGetter):
+		case errors.Is(err, consensus_types.ErrUnsupportedField):
 		case err != nil:
 			return err
 		default:
@@ -120,7 +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/metrics.go
+++ b/beacon-chain/blockchain/metrics.go
@@ -172,11 +172,15 @@ var (
 	})
 	onBlockProcessingTime = promauto.NewSummary(prometheus.SummaryOpts{
 		Name: "on_block_processing_milliseconds",
-		Help: "Total time in milliseconds to complete a call to onBlock()",
+		Help: "Total time in milliseconds to complete a call to postBlockProcess()",
 	})
 	stateTransitionProcessingTime = promauto.NewSummary(prometheus.SummaryOpts{
 		Name: "state_transition_processing_milliseconds",
-		Help: "Total time to call a state transition in onBlock()",
+		Help: "Total time to call a state transition in validateStateTransition()",
+	})
+	chainServiceProcessingTime = promauto.NewSummary(prometheus.SummaryOpts{
+		Name: "chain_service_processing_milliseconds",
+		Help: "Total time to call a chain service in ReceiveBlock()",
 	})
 	processAttsElapsedTime = promauto.NewHistogram(
 		prometheus.HistogramOpts{
@@ -246,40 +250,45 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	slashingBalance := uint64(0)
 	slashingEffectiveBalance := uint64(0)

-	for i, validator := range postState.Validators() {
+	for i := 0; i < postState.NumValidators(); i++ {
+		validator, err := postState.ValidatorAtIndexReadOnly(primitives.ValidatorIndex(i))
+		if err != nil {
+			log.WithError(err).Error("Could not load validator")
+			continue
+		}
 		bal, err := postState.BalanceAtIndex(primitives.ValidatorIndex(i))
 		if err != nil {
 			log.WithError(err).Error("Could not load validator balance")
 			continue
 		}
-		if validator.Slashed {
-			if currentEpoch < validator.ExitEpoch {
+		if validator.Slashed() {
+			if currentEpoch < validator.ExitEpoch() {
 				slashingInstances++
 				slashingBalance += bal
-				slashingEffectiveBalance += validator.EffectiveBalance
+				slashingEffectiveBalance += validator.EffectiveBalance()
 			} else {
 				slashedInstances++
 			}
 			continue
 		}
-		if validator.ExitEpoch != params.BeaconConfig().FarFutureEpoch {
-			if currentEpoch < validator.ExitEpoch {
+		if validator.ExitEpoch() != params.BeaconConfig().FarFutureEpoch {
+			if currentEpoch < validator.ExitEpoch() {
 				exitingInstances++
 				exitingBalance += bal
-				exitingEffectiveBalance += validator.EffectiveBalance
+				exitingEffectiveBalance += validator.EffectiveBalance()
 			} else {
 				exitedInstances++
 			}
 			continue
 		}
-		if currentEpoch < validator.ActivationEpoch {
+		if currentEpoch < validator.ActivationEpoch() {
 			pendingInstances++
 			pendingBalance += bal
 			continue
 		}
 		activeInstances++
 		activeBalance += bal
-		activeEffectiveBalance += validator.EffectiveBalance
+		activeEffectiveBalance += validator.EffectiveBalance()
 	}
 	activeInstances += exitingInstances + slashingInstances
 	activeBalance += exitingBalance + slashingBalance
--- a/beacon-chain/blockchain/options.go
+++ b/beacon-chain/blockchain/options.go
@@ -172,3 +172,10 @@ func WithClockSynchronizer(gs *startup.ClockSynchronizer) Option {
 		return nil
 	}
 }
+
+func WithSyncComplete(c chan struct{}) Option {
+	return func(s *Service) error {
+		s.syncComplete = c
+		return nil
+	}
+}
--- a/beacon-chain/blockchain/process_block.go
+++ b/beacon-chain/blockchain/process_block.go
@@ -22,7 +22,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v4/monitoring/tracing"
-	ethpbv1 "github.com/prysmaticlabs/prysm/v4/proto/eth/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1/attestation"
 	"github.com/prysmaticlabs/prysm/v4/runtime/version"
@@ -40,59 +39,11 @@ const depositDeadline = 20 * time.Second
 // This defines size of the upper bound for initial sync block cache.
 var initialSyncBlockCacheSize = uint64(2 * params.BeaconConfig().SlotsPerEpoch)

-// onBlock is called when a gossip block is received. It runs regular state transition on the block.
-// The block's signing root should be computed before calling this method to avoid redundant
-// computation in this method and methods it calls into.
-//
-// Spec pseudocode definition:
-//
-//	def on_block(store: Store, signed_block: ReadOnlySignedBeaconBlock) -> None:
-//	 block = signed_block.message
-//	 # Parent block must be known
-//	 assert block.parent_root in store.block_states
-//	 # Make a copy of the state to avoid mutability issues
-//	 pre_state = copy(store.block_states[block.parent_root])
-//	 # Blocks cannot be in the future. If they are, their consideration must be delayed until the are in the past.
-//	 assert get_current_slot(store) >= block.slot
-//
-//	 # Check that block is later than the finalized epoch slot (optimization to reduce calls to get_ancestor)
-//	 finalized_slot = compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
-//	 assert block.slot > finalized_slot
-//	 # Check block is a descendant of the finalized block at the checkpoint finalized slot
-//	 assert get_ancestor(store, block.parent_root, finalized_slot) == store.finalized_checkpoint.root
-//
-//	 # Check the block is valid and compute the post-state
-//	 state = pre_state.copy()
-//	 state_transition(state, signed_block, True)
-//	 # Add new block to the store
-//	 store.blocks[hash_tree_root(block)] = block
-//	 # Add new state for this block to the store
-//	 store.block_states[hash_tree_root(block)] = state
-//
-//	 # Update justified checkpoint
-//	 if state.current_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
-//	     if state.current_justified_checkpoint.epoch > store.best_justified_checkpoint.epoch:
-//	         store.best_justified_checkpoint = state.current_justified_checkpoint
-//	     if should_update_justified_checkpoint(store, state.current_justified_checkpoint):
-//	         store.justified_checkpoint = state.current_justified_checkpoint
-//
-//	 # Update finalized checkpoint
-//	 if state.finalized_checkpoint.epoch > store.finalized_checkpoint.epoch:
-//	     store.finalized_checkpoint = state.finalized_checkpoint
-//
-//	     # Potentially update justified if different from store
-//	     if store.justified_checkpoint != state.current_justified_checkpoint:
-//	         # Update justified if new justified is later than store justified
-//	         if state.current_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
-//	             store.justified_checkpoint = state.current_justified_checkpoint
-//	             return
-//
-//	         # Update justified if store justified is not in chain with finalized checkpoint
-//	         finalized_slot = compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
-//	         ancestor_at_finalized_slot = get_ancestor(store, store.justified_checkpoint.root, finalized_slot)
-//	         if ancestor_at_finalized_slot != store.finalized_checkpoint.root:
-//	             store.justified_checkpoint = state.current_justified_checkpoint
-func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte) error {
+// postBlockProcess is called when a gossip block is received. This function performs
+// several duties most importantly informing the engine if head was updated,
+// saving the new head information to the blockchain package and
+// handling attestations, slashings and similar included in the block.
+func (s *Service) postBlockProcess(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte, postState state.BeaconState, isValidPayload bool) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlock")
 	defer span.End()
 	if err := consensusblocks.BeaconBlockIsNil(signed); err != nil {
@@ -101,52 +52,7 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 	startTime := time.Now()
 	b := signed.Block()

-	preState, err := s.getBlockPreState(ctx, b)
-	if err != nil {
-		return err
-	}
-
-	// Verify that the parent block is in forkchoice
-	if !s.cfg.ForkChoiceStore.HasNode(b.ParentRoot()) {
-		return ErrNotDescendantOfFinalized
-	}
-
-	// Save current justified and finalized epochs for future use.
-	currStoreJustifiedEpoch := s.cfg.ForkChoiceStore.JustifiedCheckpoint().Epoch
-	currStoreFinalizedEpoch := s.cfg.ForkChoiceStore.FinalizedCheckpoint().Epoch
-	preStateFinalizedEpoch := preState.FinalizedCheckpoint().Epoch
-	preStateJustifiedEpoch := preState.CurrentJustifiedCheckpoint().Epoch
-
-	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
-	if err != nil {
-		return err
-	}
-	stateTransitionStartTime := time.Now()
-	postState, err := transition.ExecuteStateTransition(ctx, preState, signed)
-	if err != nil {
-		return invalidBlock{error: err}
-	}
-	stateTransitionProcessingTime.Observe(float64(time.Since(stateTransitionStartTime).Milliseconds()))
-
-	postStateVersion, postStateHeader, err := getStateVersionAndPayload(postState)
-	if err != nil {
-		return err
-	}
-	isValidPayload, err := s.notifyNewPayload(ctx, postStateVersion, postStateHeader, signed)
-	if err != nil {
-		return errors.Wrap(err, "could not validate new payload")
-	}
-	if 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 {
@@ -160,34 +66,6 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 		}
 	}

-	// If slasher is configured, forward the attestations in the block via
-	// an event feed for processing.
-	if features.Get().EnableSlasher {
-		// Feed the indexed attestation to slasher if enabled. This action
-		// is done in the background to avoid adding more load to this critical code path.
-		go func() {
-			// Using a different context to prevent timeouts as this operation can be expensive
-			// and we want to avoid affecting the critical code path.
-			ctx := context.TODO()
-			for _, att := range signed.Block().Body().Attestations() {
-				committee, err := helpers.BeaconCommitteeFromState(ctx, preState, att.Data.Slot, att.Data.CommitteeIndex)
-				if err != nil {
-					log.WithError(err).Error("Could not get attestation committee")
-					tracing.AnnotateError(span, err)
-					return
-				}
-				indexedAtt, err := attestation.ConvertToIndexed(ctx, att, committee)
-				if err != nil {
-					log.WithError(err).Error("Could not convert to indexed attestation")
-					tracing.AnnotateError(span, err)
-					return
-				}
-				s.cfg.SlasherAttestationsFeed.Send(indexedAtt)
-			}
-		}()
-	}
-
-	justified := s.cfg.ForkChoiceStore.JustifiedCheckpoint()
 	start := time.Now()
 	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx)
 	if err != nil {
@@ -208,18 +86,6 @@ 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()))

@@ -229,6 +95,12 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 		return err
 	}

+	optimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(blockRoot)
+	if err != nil {
+		log.WithError(err).Debug("Could not check if block is optimistic")
+		optimistic = true
+	}
+
 	// Send notification of the processed block to the state feed.
 	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 		Type: statefeed.BlockProcessed,
@@ -237,56 +109,34 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.ReadOnlySignedB
 			BlockRoot:   blockRoot,
 			SignedBlock: signed,
 			Verified:    true,
+			Optimistic:  optimistic,
 		},
 	})

-	// Save justified check point to db.
-	postStateJustifiedEpoch := postState.CurrentJustifiedCheckpoint().Epoch
-	if justified.Epoch > currStoreJustifiedEpoch || (justified.Epoch == postStateJustifiedEpoch && justified.Epoch > preStateJustifiedEpoch) {
-		if err := s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{
-			Epoch: justified.Epoch, Root: justified.Root[:],
-		}); err != nil {
-			return err
-		}
-	}
-
-	// Save finalized check point to db and more.
-	postStateFinalizedEpoch := postState.FinalizedCheckpoint().Epoch
-	finalized := s.cfg.ForkChoiceStore.FinalizedCheckpoint()
-	if finalized.Epoch > currStoreFinalizedEpoch || (finalized.Epoch == postStateFinalizedEpoch && finalized.Epoch > preStateFinalizedEpoch) {
-		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()
-			s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
-				Type: statefeed.FinalizedCheckpoint,
-				Data: &ethpbv1.EventFinalizedCheckpoint{
-					Epoch:               postState.FinalizedCheckpoint().Epoch,
-					Block:               postState.FinalizedCheckpoint().Root,
-					State:               stateRoot[:],
-					ExecutionOptimistic: isOptimistic,
-				},
-			})
-
-			// 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.
-			depCtx, cancel := context.WithTimeout(context.Background(), depositDeadline)
-			defer cancel()
-			if err := s.insertFinalizedDeposits(depCtx, finalized.Root); err != nil {
-				log.WithError(err).Error("Could not insert finalized deposits.")
-			}
-		}()
-	}
 	defer reportAttestationInclusion(b)
-	if err := s.handleEpochBoundary(ctx, postState); err != nil {
-		return err
+	if headRoot == blockRoot {
+		// Updating next slot state cache can happen in the background
+		// except in the epoch boundary in which case we lock to handle
+		// the shuffling and proposer caches updates.
+		// We handle these caches only on canonical
+		// blocks, otherwise this will be handled by lateBlockTasks
+		slot := postState.Slot()
+		if slots.IsEpochEnd(slot) {
+			if err := transition.UpdateNextSlotCache(ctx, blockRoot[:], postState); err != nil {
+				return errors.Wrap(err, "could not update next slot state cache")
+			}
+			if err := s.handleEpochBoundary(ctx, slot, postState, blockRoot[:]); err != nil {
+				return errors.Wrap(err, "could not handle epoch boundary")
+			}
+		} else {
+			go func() {
+				slotCtx, cancel := context.WithTimeout(context.Background(), slotDeadline)
+				defer cancel()
+				if err := transition.UpdateNextSlotCache(slotCtx, blockRoot[:], postState); err != nil {
+					log.WithError(err).Error("could not update next slot state cache")
+				}
+			}()
+		}
 	}
 	onBlockProcessingTime.Observe(float64(time.Since(startTime).Milliseconds()))
 	return nil
@@ -409,7 +259,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.ReadOnlySi
 			postVersionAndHeaders[i].version,
 			postVersionAndHeaders[i].header, b)
 		if err != nil {
-			return err
+			return s.handleInvalidExecutionError(ctx, err, blockRoots[i], b.Block().ParentRoot())
 		}
 		if isValidPayload {
 			if err := s.validateMergeTransitionBlock(ctx, preVersionAndHeaders[i].version,
@@ -479,70 +329,51 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.ReadOnlySi
 	if _, err := s.notifyForkchoiceUpdate(ctx, arg); err != nil {
 		return err
 	}
-	return s.saveHeadNoDB(ctx, lastB, lastBR, preState)
+	return s.saveHeadNoDB(ctx, lastB, lastBR, preState, !isValidPayload)
 }

-// Epoch boundary bookkeeping such as logging epoch summaries.
-func (s *Service) handleEpochBoundary(ctx context.Context, postState state.BeaconState) error {
-	ctx, span := trace.StartSpan(ctx, "blockChain.handleEpochBoundary")
-	defer span.End()
-
-	var err error
-	if postState.Slot()+1 == s.nextEpochBoundarySlot {
-		copied := postState.Copy()
-		copied, err := transition.ProcessSlots(ctx, copied, copied.Slot()+1)
-		if err != nil {
-			return err
-		}
-		// Update caches for the next epoch at epoch boundary slot - 1.
-		if err := helpers.UpdateCommitteeCache(ctx, copied, coreTime.CurrentEpoch(copied)); err != nil {
-			return err
-		}
-		if err := helpers.UpdateProposerIndicesInCache(ctx, copied); err != nil {
-			return err
-		}
-	} else if postState.Slot() >= s.nextEpochBoundarySlot {
-		s.nextEpochBoundarySlot, err = slots.EpochStart(coreTime.NextEpoch(postState))
-		if err != nil {
-			return err
-		}
-
-		// Update caches at epoch boundary slot.
-		// The following updates have shortcut to return nil cheaply if fulfilled during boundary slot - 1.
-		if err := helpers.UpdateCommitteeCache(ctx, postState, coreTime.CurrentEpoch(postState)); err != nil {
-			return err
-		}
-		if err := helpers.UpdateProposerIndicesInCache(ctx, postState); err != nil {
-			return err
-		}
-
-		headSt, err := s.HeadState(ctx)
-		if err != nil {
-			return err
-		}
-		if err := reportEpochMetrics(ctx, postState, headSt); err != nil {
-			return err
-		}
+func (s *Service) updateEpochBoundaryCaches(ctx context.Context, st state.BeaconState) error {
+	e := coreTime.CurrentEpoch(st)
+	if err := helpers.UpdateCommitteeCache(ctx, st, e); err != nil {
+		return errors.Wrap(err, "could not update committee cache")
 	}
-
+	if err := helpers.UpdateProposerIndicesInCache(ctx, st, e); err != nil {
+		return errors.Wrap(err, "could not update proposer index cache")
+	}
+	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.UpdateCommitteeCache(slotCtx, st, e+1); err != nil {
+			log.WithError(err).Warn("Could not update committee cache")
+		}
+		if err := helpers.UpdateProposerIndicesInCache(slotCtx, st, e+1); err != nil {
+			log.WithError(err).Warn("Failed to cache next epoch proposers")
+		}
+	}()
 	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")
+// Epoch boundary tasks: it copies the headState and updates the epoch boundary
+// caches.
+func (s *Service) handleEpochBoundary(ctx context.Context, slot primitives.Slot, headState state.BeaconState, blockRoot []byte) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.handleEpochBoundary")
 	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 early if we are advancing to a past epoch
+	if slot < headState.Slot() {
+		return nil
 	}
-
-	return s.cfg.ForkChoiceStore.InsertNode(ctx, st, root)
+	if !slots.IsEpochEnd(slot) {
+		return nil
+	}
+	copied := headState.Copy()
+	copied, err := transition.ProcessSlotsUsingNextSlotCache(ctx, copied, blockRoot, slot+1)
+	if err != nil {
+		return err
+	}
+	return s.updateEpochBoundaryCaches(ctx, copied)
 }

 // This feeds in the attestations included in the block to fork choice store. It's allows fork choice store
@@ -651,33 +482,31 @@ 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) spawnLateBlockTasksLoop() {
-	go func() {
-		_, err := s.clockWaiter.WaitForClock(s.ctx)
-		if err != nil {
-			log.WithError(err).Error("spawnLateBlockTasksLoop encountered an error waiting for initialization")
+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():
+			log.Debug("Context closed, exiting routine")
 			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():
-				log.Debug("Context closed, exiting routine")
-				return
-			}
-		}
-	}()
+	}
 }

 // 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.
+// it also updates the next slot cache and the proposer index cache to deal with skipped slots.
 func (s *Service) lateBlockTasks(ctx context.Context) {
+	currentSlot := s.CurrentSlot()
 	if s.CurrentSlot() == s.HeadSlot() {
 		return
 	}
@@ -685,12 +514,30 @@ func (s *Service) lateBlockTasks(ctx context.Context) {
 		Type: statefeed.MissedSlot,
 	})

+	s.headLock.RLock()
+	headRoot := s.headRoot()
+	headState := s.headState(ctx)
+	s.headLock.RUnlock()
+	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")
+	}
+	if err := s.handleEpochBoundary(ctx, currentSlot, headState, headRoot[:]); err != nil {
+		log.WithError(err).Error("lateBlockTasks: could not update epoch boundary caches")
+	}
 	// 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 && !features.Get().PrepareAllPayloads) || id != [8]byte{} {
 		return
 	}
+
 	s.headLock.RLock()
 	headBlock, err := s.headBlock()
 	if err != nil {
@@ -698,8 +545,6 @@ func (s *Service) lateBlockTasks(ctx context.Context) {
 		log.WithError(err).Debug("could not perform late block tasks: failed to retrieve head block")
 		return
 	}
-	headRoot := s.headRoot()
-	headState := s.headState(ctx)
 	s.headLock.RUnlock()
 	_, err = s.notifyForkchoiceUpdate(ctx, &notifyForkchoiceUpdateArg{
 		headState: headState,
@@ -709,11 +554,21 @@ func (s *Service) lateBlockTasks(ctx context.Context) {
 	if err != nil {
 		log.WithError(err).Debug("could not perform late block tasks: failed to update forkchoice with engine")
 	}
-	lastRoot, lastState := transition.LastCachedState()
-	if lastState == nil {
-		lastRoot, lastState = headRoot[:], headState
-	}
-	if err = transition.UpdateNextSlotCache(ctx, lastRoot, lastState); err != nil {
-		log.WithError(err).Debug("could not update next slot state cache")
+}
+
+// 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")
 	}
 }
+
+func (s *Service) handleInvalidExecutionError(ctx context.Context, err error, blockRoot [32]byte, parentRoot [32]byte) error {
+	if IsInvalidBlock(err) && InvalidBlockLVH(err) != [32]byte{} {
+		return s.pruneInvalidBlock(ctx, blockRoot, parentRoot, InvalidBlockLVH(err))
+	}
+	return err
+}
--- a/beacon-chain/blockchain/process_block_helpers.go
+++ b/beacon-chain/blockchain/process_block_helpers.go
@@ -14,6 +14,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
 	mathutil "github.com/prysmaticlabs/prysm/v4/math"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/time"
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 	"go.opencensus.io/trace"
 )
@@ -209,35 +210,44 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk interfa
 	return s.cfg.ForkChoiceStore.InsertChain(ctx, pendingNodes)
 }

-// inserts finalized deposits into our finalized deposit trie.
-func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) error {
+// inserts finalized deposits into our finalized deposit trie, needs to be
+// called in the background
+func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.insertFinalizedDeposits")
 	defer span.End()
+	startTime := time.Now()

 	// Update deposit cache.
 	finalizedState, err := s.cfg.StateGen.StateByRoot(ctx, fRoot)
 	if err != nil {
-		return errors.Wrap(err, "could not fetch finalized state")
+		log.WithError(err).Error("could not fetch finalized state")
+		return
 	}
 	// We update the cache up to the last deposit index in the finalized block's state.
 	// We can be confident that these deposits will be included in some block
 	// because the Eth1 follow distance makes such long-range reorgs extremely unlikely.
 	eth1DepositIndex, err := mathutil.Int(finalizedState.Eth1DepositIndex())
 	if err != nil {
-		return errors.Wrap(err, "could not cast eth1 deposit index")
+		log.WithError(err).Error("could not cast eth1 deposit index")
+		return
 	}
 	// The deposit index in the state is always the index of the next deposit
 	// 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
-	if err = s.cfg.DepositCache.InsertFinalizedDeposits(ctx, int64(eth1DepositIndex)); err != nil {
-		return err
+	finalizedEth1DepIdx := eth1DepositIndex - 1
+	if err = s.cfg.DepositCache.InsertFinalizedDeposits(ctx, int64(finalizedEth1DepIdx)); err != nil {
+		log.WithError(err).Error("could not insert finalized deposits")
+		return
 	}
 	// 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")
+	if err = s.cfg.DepositCache.PruneProofs(ctx, int64(finalizedEth1DepIdx)); err != nil {
+		log.WithError(err).Error("could not prune deposit proofs")
 	}
-	return nil
+	// Prune deposits which have already been finalized, the below method prunes all pending deposits (non-inclusive) up
+	// to the provided eth1 deposit index.
+	s.cfg.DepositCache.PrunePendingDeposits(ctx, int64(eth1DepositIndex)) // lint:ignore uintcast -- Deposit index should not exceed int64 in your lifetime.
+
+	log.WithField("duration", time.Since(startTime).String()).Debug("Finalized deposit insertion completed")
 }

 // This ensures that the input root defaults to using genesis root instead of zero hashes. This is needed for handling
--- a/beacon-chain/blockchain/process_block_test.go
+++ b/beacon-chain/blockchain/process_block_test.go
@@ -41,103 +41,6 @@ import (
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

-func TestStore_OnBlock(t *testing.T) {
-	service, tr := minimalTestService(t)
-	ctx, beaconDB, fcs := tr.ctx, tr.db, tr.fcs
-
-	var genesisStateRoot [32]byte
-	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
-	util.SaveBlock(t, ctx, beaconDB, genesis)
-	validGenesisRoot, err := genesis.Block.HashTreeRoot()
-	require.NoError(t, err)
-	st, err := util.NewBeaconState()
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
-	ojc := &ethpb.Checkpoint{}
-	stfcs, root, err := prepareForkchoiceState(ctx, 0, validGenesisRoot, [32]byte{}, [32]byte{}, ojc, ojc)
-	require.NoError(t, err)
-	require.NoError(t, fcs.InsertNode(ctx, stfcs, root))
-	roots, err := blockTree1(t, beaconDB, validGenesisRoot[:])
-	require.NoError(t, err)
-	random := util.NewBeaconBlock()
-	random.Block.Slot = 1
-	random.Block.ParentRoot = validGenesisRoot[:]
-	util.SaveBlock(t, ctx, beaconDB, random)
-	randomParentRoot, err := random.Block.HashTreeRoot()
-	assert.NoError(t, err)
-
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Slot: st.Slot(), Root: randomParentRoot[:]}))
-	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), randomParentRoot))
-	randomParentRoot2 := roots[1]
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Slot: st.Slot(), Root: randomParentRoot2}))
-	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), bytesutil.ToBytes32(randomParentRoot2)))
-	stfcs, root, err = prepareForkchoiceState(ctx, 2, bytesutil.ToBytes32(randomParentRoot2),
-		validGenesisRoot, [32]byte{'r'}, ojc, ojc)
-	require.NoError(t, err)
-	require.NoError(t, fcs.InsertNode(ctx, stfcs, root))
-
-	tests := []struct {
-		name          string
-		blk           *ethpb.SignedBeaconBlock
-		s             state.BeaconState
-		time          uint64
-		wantErrString string
-	}{
-		{
-			name:          "parent block root does not have a state",
-			blk:           util.NewBeaconBlock(),
-			s:             st.Copy(),
-			wantErrString: "could not reconstruct parent state",
-		},
-		{
-			name: "block is from the future",
-			blk: func() *ethpb.SignedBeaconBlock {
-				b := util.NewBeaconBlock()
-				b.Block.ParentRoot = randomParentRoot2
-				b.Block.Slot = params.BeaconConfig().FarFutureSlot
-				return b
-			}(),
-			s:             st.Copy(),
-			wantErrString: "is in the far distant future",
-		},
-		{
-			name: "could not get finalized block",
-			blk: func() *ethpb.SignedBeaconBlock {
-				b := util.NewBeaconBlock()
-				b.Block.ParentRoot = randomParentRoot[:]
-				b.Block.Slot = 2
-				return b
-			}(),
-			s:             st.Copy(),
-			wantErrString: "not descendant of finalized checkpoint",
-		},
-		{
-			name: "same slot as finalized block",
-			blk: func() *ethpb.SignedBeaconBlock {
-				b := util.NewBeaconBlock()
-				b.Block.Slot = 0
-				b.Block.ParentRoot = randomParentRoot2
-				return b
-			}(),
-			s:             st.Copy(),
-			wantErrString: "block is equal or earlier than finalized block, slot 0 < slot 0",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			fRoot := bytesutil.ToBytes32(roots[0])
-			require.NoError(t, service.cfg.ForkChoiceStore.UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Root: fRoot}))
-			root, err := tt.blk.Block.HashTreeRoot()
-			assert.NoError(t, err)
-			wsb, err := consensusblocks.NewSignedBeaconBlock(tt.blk)
-			require.NoError(t, err)
-			err = service.onBlock(ctx, wsb, root)
-			assert.ErrorContains(t, tt.wantErrString, err)
-		})
-	}
-}
-
 func TestStore_OnBlockBatch(t *testing.T) {
 	service, tr := minimalTestService(t)
 	ctx := tr.ctx
@@ -636,8 +539,7 @@ 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.Equal(t, 3*params.BeaconConfig().SlotsPerEpoch, service.nextEpochBoundarySlot)
+	require.NoError(t, service.handleEpochBoundary(ctx, s.Slot(), s, []byte{}))
 }

 func TestOnBlock_CanFinalize_WithOnTick(t *testing.T) {
@@ -657,7 +559,20 @@ func TestOnBlock_CanFinalize_WithOnTick(t *testing.T) {
 		wsb, err := consensusblocks.NewSignedBeaconBlock(blk)
 		require.NoError(t, err)
 		require.NoError(t, fcs.NewSlot(ctx, i))
-		require.NoError(t, service.onBlock(ctx, wsb, r))
+		// Save current justified and finalized epochs for future use.
+		currStoreJustifiedEpoch := service.CurrentJustifiedCheckpt().Epoch
+		currStoreFinalizedEpoch := service.FinalizedCheckpt().Epoch
+
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, r, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, r, postState, true))
+		require.NoError(t, service.updateJustificationOnBlock(ctx, preState, postState, currStoreJustifiedEpoch))
+		_, err = service.updateFinalizationOnBlock(ctx, preState, postState, currStoreFinalizedEpoch)
+		require.NoError(t, err)
+
 		testState, err = service.cfg.StateGen.StateByRoot(ctx, r)
 		require.NoError(t, err)
 	}
@@ -692,7 +607,20 @@ func TestOnBlock_CanFinalize(t *testing.T) {
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(blk)
 		require.NoError(t, err)
-		require.NoError(t, service.onBlock(ctx, wsb, r))
+		// Save current justified and finalized epochs for future use.
+		currStoreJustifiedEpoch := service.CurrentJustifiedCheckpt().Epoch
+		currStoreFinalizedEpoch := service.FinalizedCheckpt().Epoch
+
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, r, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, r, postState, true))
+		require.NoError(t, service.updateJustificationOnBlock(ctx, preState, postState, currStoreJustifiedEpoch))
+		_, err = service.updateFinalizationOnBlock(ctx, preState, postState, currStoreFinalizedEpoch)
+		require.NoError(t, err)
+
 		testState, err = service.cfg.StateGen.StateByRoot(ctx, r)
 		require.NoError(t, err)
 	}
@@ -714,8 +642,7 @@ func TestOnBlock_CanFinalize(t *testing.T) {

 func TestOnBlock_NilBlock(t *testing.T) {
 	service, tr := minimalTestService(t)
-
-	err := service.onBlock(tr.ctx, nil, [32]byte{})
+	err := service.postBlockProcess(tr.ctx, nil, [32]byte{}, nil, true)
 	require.Equal(t, true, IsInvalidBlock(err))
 }

@@ -729,11 +656,11 @@ func TestOnBlock_InvalidSignature(t *testing.T) {
 	blk, err := util.GenerateFullBlock(gs, keys, util.DefaultBlockGenConfig(), 1)
 	require.NoError(t, err)
 	blk.Signature = []byte{'a'} // Mutate the signature.
-	r, err := blk.Block.HashTreeRoot()
-	require.NoError(t, err)
 	wsb, err := consensusblocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, r)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	_, err = service.validateStateTransition(ctx, preState, wsb)
 	require.Equal(t, true, IsInvalidBlock(err))
 }

@@ -757,7 +684,13 @@ func TestOnBlock_CallNewPayloadAndForkchoiceUpdated(t *testing.T) {
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(blk)
 		require.NoError(t, err)
-		require.NoError(t, service.onBlock(ctx, wsb, r))
+
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, r, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, r, postState, false))
 		testState, err = service.cfg.StateGen.StateByRoot(ctx, r)
 		require.NoError(t, err)
 	}
@@ -783,7 +716,7 @@ func TestInsertFinalizedDeposits(t *testing.T) {
 			Signature:             zeroSig[:],
 		}, Proof: [][]byte{root}}, 100+i, int64(i), bytesutil.ToBytes32(root)))
 	}
-	assert.NoError(t, service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k'}))
+	service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k'})
 	fDeposits := depositCache.FinalizedDeposits(ctx)
 	assert.Equal(t, 7, int(fDeposits.MerkleTrieIndex), "Finalized deposits not inserted correctly")
 	deps := depositCache.AllDeposits(ctx, big.NewInt(107))
@@ -792,6 +725,45 @@ func TestInsertFinalizedDeposits(t *testing.T) {
 	}
 }

+func TestInsertFinalizedDeposits_PrunePendingDeposits(t *testing.T) {
+	service, tr := minimalTestService(t)
+	ctx, depositCache := tr.ctx, tr.dc
+
+	gs, _ := util.DeterministicGenesisState(t, 32)
+	require.NoError(t, service.saveGenesisData(ctx, gs))
+	gs = gs.Copy()
+	assert.NoError(t, gs.SetEth1Data(&ethpb.Eth1Data{DepositCount: 10}))
+	assert.NoError(t, gs.SetEth1DepositIndex(8))
+	assert.NoError(t, service.cfg.StateGen.SaveState(ctx, [32]byte{'m', 'o', 'c', 'k'}, gs))
+	var zeroSig [96]byte
+	for i := uint64(0); i < uint64(4*params.BeaconConfig().SlotsPerEpoch); i++ {
+		root := []byte(strconv.Itoa(int(i)))
+		assert.NoError(t, depositCache.InsertDeposit(ctx, &ethpb.Deposit{Data: &ethpb.Deposit_Data{
+			PublicKey:             bytesutil.FromBytes48([fieldparams.BLSPubkeyLength]byte{}),
+			WithdrawalCredentials: params.BeaconConfig().ZeroHash[:],
+			Amount:                0,
+			Signature:             zeroSig[:],
+		}, Proof: [][]byte{root}}, 100+i, int64(i), bytesutil.ToBytes32(root)))
+		depositCache.InsertPendingDeposit(ctx, &ethpb.Deposit{Data: &ethpb.Deposit_Data{
+			PublicKey:             bytesutil.FromBytes48([fieldparams.BLSPubkeyLength]byte{}),
+			WithdrawalCredentials: params.BeaconConfig().ZeroHash[:],
+			Amount:                0,
+			Signature:             zeroSig[:],
+		}, Proof: [][]byte{root}}, 100+i, int64(i), bytesutil.ToBytes32(root))
+	}
+	service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k'})
+	fDeposits := depositCache.FinalizedDeposits(ctx)
+	assert.Equal(t, 7, int(fDeposits.MerkleTrieIndex), "Finalized deposits not inserted correctly")
+	deps := depositCache.AllDeposits(ctx, big.NewInt(107))
+	for _, d := range deps {
+		assert.DeepEqual(t, [][]byte(nil), d.Proof, "Proofs are not empty")
+	}
+	pendingDeps := depositCache.PendingContainers(ctx, nil)
+	for _, d := range pendingDeps {
+		assert.DeepEqual(t, true, d.Index >= 8, "Pending deposits were not pruned")
+	}
+}
+
 func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
 	service, tr := minimalTestService(t)
 	ctx, depositCache := tr.ctx, tr.dc
@@ -819,7 +791,7 @@ func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
 	// Insert 3 deposits before hand.
 	require.NoError(t, depositCache.InsertFinalizedDeposits(ctx, 2))

-	assert.NoError(t, service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k'}))
+	service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k'})
 	fDeposits := depositCache.FinalizedDeposits(ctx)
 	assert.Equal(t, 5, int(fDeposits.MerkleTrieIndex), "Finalized deposits not inserted correctly")

@@ -829,7 +801,7 @@ func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
 	}

 	// Insert New Finalized State with higher deposit count.
-	assert.NoError(t, service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k', '2'}))
+	service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k', '2'})
 	fDeposits = depositCache.FinalizedDeposits(ctx)
 	assert.Equal(t, 12, int(fDeposits.MerkleTrieIndex), "Finalized deposits not inserted correctly")
 	deps = depositCache.AllDeposits(ctx, big.NewInt(112))
@@ -1131,19 +1103,35 @@ func TestOnBlock_ProcessBlocksParallel(t *testing.T) {
 		var wg sync.WaitGroup
 		wg.Add(4)
 		go func() {
-			require.NoError(t, service.onBlock(ctx, wsb1, r1))
+			preState, err := service.getBlockPreState(ctx, wsb1.Block())
+			require.NoError(t, err)
+			postState, err := service.validateStateTransition(ctx, preState, wsb1)
+			require.NoError(t, err)
+			require.NoError(t, service.postBlockProcess(ctx, wsb1, r1, postState, true))
 			wg.Done()
 		}()
 		go func() {
-			require.NoError(t, service.onBlock(ctx, wsb2, r2))
+			preState, err := service.getBlockPreState(ctx, wsb2.Block())
+			require.NoError(t, err)
+			postState, err := service.validateStateTransition(ctx, preState, wsb2)
+			require.NoError(t, err)
+			require.NoError(t, service.postBlockProcess(ctx, wsb2, r2, postState, true))
 			wg.Done()
 		}()
 		go func() {
-			require.NoError(t, service.onBlock(ctx, wsb3, r3))
+			preState, err := service.getBlockPreState(ctx, wsb3.Block())
+			require.NoError(t, err)
+			postState, err := service.validateStateTransition(ctx, preState, wsb3)
+			require.NoError(t, err)
+			require.NoError(t, service.postBlockProcess(ctx, wsb3, r3, postState, true))
 			wg.Done()
 		}()
 		go func() {
-			require.NoError(t, service.onBlock(ctx, wsb4, r4))
+			preState, err := service.getBlockPreState(ctx, wsb4.Block())
+			require.NoError(t, err)
+			postState, err := service.validateStateTransition(ctx, preState, wsb4)
+			require.NoError(t, err)
+			require.NoError(t, service.postBlockProcess(ctx, wsb4, r4, postState, true))
 			wg.Done()
 		}()
 		wg.Wait()
@@ -1211,7 +1199,13 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		require.NoError(t, service.onBlock(ctx, wsb, root))
+
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, root, postState, false))
 	}

 	for i := 6; i < 12; i++ {
@@ -1224,7 +1218,12 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, root, postState, false)
 		require.NoError(t, err)
 	}

@@ -1238,7 +1237,12 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, root, postState, false)
 		require.NoError(t, err)
 	}
 	// Check that we haven't justified the second epoch yet
@@ -1255,7 +1259,12 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 	require.NoError(t, err)
 	firstInvalidRoot, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, firstInvalidRoot)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, firstInvalidRoot, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, firstInvalidRoot, postState, false)
 	require.NoError(t, err)
 	jc = service.cfg.ForkChoiceStore.JustifiedCheckpoint()
 	require.Equal(t, primitives.Epoch(2), jc.Epoch)
@@ -1278,7 +1287,12 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 	require.NoError(t, err)
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err = service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, root, postState, false)
 	require.ErrorContains(t, "received an INVALID payload from execution engine", err)
 	// Check that forkchoice's head is the last invalid block imported. The
 	// store's headroot is the previous head (since the invalid block did
@@ -1301,7 +1315,13 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 	require.NoError(t, err)
 	root, err = b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
+
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err = service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, root, postState, true)
 	require.NoError(t, err)
 	// Check the newly imported block is head, it justified the right
 	// checkpoint and the node is no longer optimistic
@@ -1358,7 +1378,12 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		require.NoError(t, service.onBlock(ctx, wsb, root))
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, root, postState, false))
 	}

 	for i := 6; i < 12; i++ {
@@ -1371,7 +1396,12 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, root, postState, false)
 		require.NoError(t, err)
 	}

@@ -1385,7 +1415,13 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
+
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, root, postState, false)
 		require.NoError(t, err)
 	}
 	// Check that we haven't justified the second epoch yet
@@ -1402,7 +1438,12 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 	require.NoError(t, err)
 	firstInvalidRoot, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, firstInvalidRoot)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, firstInvalidRoot, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, firstInvalidRoot, postState, false)
 	require.NoError(t, err)
 	jc = service.cfg.ForkChoiceStore.JustifiedCheckpoint()
 	require.Equal(t, primitives.Epoch(2), jc.Epoch)
@@ -1425,7 +1466,12 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 	require.NoError(t, err)
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
+
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
+	require.NoError(t, err)
+	_, err = service.validateExecutionOnBlock(ctx, preStateVersion, preStateHeader, wsb, root)
 	require.ErrorContains(t, "received an INVALID payload from execution engine", err)
 	// Check that forkchoice's head and store's headroot are the previous head (since the invalid block did
 	// not finish importing and it was never imported to forkchoice). Check
@@ -1448,7 +1494,12 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 	require.NoError(t, err)
 	root, err = b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err = service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, root, postState, true)
 	require.NoError(t, err)
 	// Check the newly imported block is head, it justified the right
 	// checkpoint and the node is no longer optimistic
@@ -1506,7 +1557,13 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		require.NoError(t, service.onBlock(ctx, wsb, root))
+
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, root, postState, false))
 	}

 	for i := 6; i < 12; i++ {
@@ -1519,7 +1576,13 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
+
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, root, postState, false)
 		require.NoError(t, err)
 	}

@@ -1533,7 +1596,12 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	require.NoError(t, err)
 	lastValidRoot, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, lastValidRoot)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, lastValidRoot, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, lastValidRoot, postState, false)
 	require.NoError(t, err)
 	// save the post state and the payload Hash of this block since it will
 	// be the LVH
@@ -1555,7 +1623,12 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 		require.NoError(t, err)
 		invalidRoots[i-13], err = b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, invalidRoots[i-13])
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, invalidRoots[i-13], wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, invalidRoots[i-13], postState, false)
 		require.NoError(t, err)
 	}
 	// Check that we have justified the second epoch
@@ -1576,7 +1649,12 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	require.NoError(t, err)
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
+
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
+	require.NoError(t, err)
+	_, err = service.validateExecutionOnBlock(ctx, preStateVersion, preStateHeader, wsb, root)
 	require.ErrorContains(t, "received an INVALID payload from execution engine", err)

 	// Check that forkchoice's head and store's headroot are the previous head (since the invalid block did
@@ -1610,7 +1688,12 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	require.NoError(t, err)
 	root, err = b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, service.onBlock(ctx, wsb, root))
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err = service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+	require.NoError(t, service.postBlockProcess(ctx, wsb, root, postState, true))
 	// Check that the head is still INVALID and the node is still optimistic
 	require.Equal(t, invalidHeadRoot, service.cfg.ForkChoiceStore.CachedHeadRoot())
 	optimistic, err = service.IsOptimistic(ctx)
@@ -1628,7 +1711,12 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, root, postState, true)
 		require.NoError(t, err)
 		st, err = service.cfg.StateGen.StateByRoot(ctx, root)
 		require.NoError(t, err)
@@ -1648,7 +1736,13 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	require.NoError(t, err)
 	root, err = b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
+
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err = service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, root, postState, true)
 	require.NoError(t, err)
 	require.Equal(t, root, service.cfg.ForkChoiceStore.CachedHeadRoot())
 	sjc = service.CurrentJustifiedCheckpt()
@@ -1699,7 +1793,12 @@ func TestNoViableHead_Reboot(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		require.NoError(t, service.onBlock(ctx, wsb, root))
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, root, postState, false))
 	}

 	for i := 6; i < 12; i++ {
@@ -1712,7 +1811,12 @@ func TestNoViableHead_Reboot(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		err = service.postBlockProcess(ctx, wsb, root, postState, false)
 		require.NoError(t, err)
 	}

@@ -1726,7 +1830,12 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	require.NoError(t, err)
 	lastValidRoot, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, lastValidRoot)
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, lastValidRoot, wsb, postState))
+	err = service.postBlockProcess(ctx, wsb, lastValidRoot, postState, false)
 	require.NoError(t, err)
 	// save the post state and the payload Hash of this block since it will
 	// be the LVH
@@ -1747,7 +1856,18 @@ func TestNoViableHead_Reboot(t *testing.T) {
 		require.NoError(t, err)
 		root, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		require.NoError(t, service.onBlock(ctx, wsb, root))
+		// Save current justified and finalized epochs for future use.
+		currStoreJustifiedEpoch := service.CurrentJustifiedCheckpt().Epoch
+		currStoreFinalizedEpoch := service.FinalizedCheckpt().Epoch
+		preState, err := service.getBlockPreState(ctx, wsb.Block())
+		require.NoError(t, err)
+		postState, err := service.validateStateTransition(ctx, preState, wsb)
+		require.NoError(t, err)
+		require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+		require.NoError(t, service.postBlockProcess(ctx, wsb, root, postState, false))
+		require.NoError(t, service.updateJustificationOnBlock(ctx, preState, postState, currStoreJustifiedEpoch))
+		_, err = service.updateFinalizationOnBlock(ctx, preState, postState, currStoreFinalizedEpoch)
+		require.NoError(t, err)
 	}
 	// Check that we have justified the second epoch
 	jc := service.cfg.ForkChoiceStore.JustifiedCheckpoint()
@@ -1766,7 +1886,11 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	require.NoError(t, err)
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
+	preState, err = service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
+	require.NoError(t, err)
+	_, err = service.validateExecutionOnBlock(ctx, preStateVersion, preStateHeader, wsb, root)
 	require.ErrorContains(t, "received an INVALID payload from execution engine", err)

 	// Check that the headroot/state are not in DB and restart the node
@@ -1848,7 +1972,12 @@ func TestOnBlock_HandleBlockAttestations(t *testing.T) {
 	require.NoError(t, err)
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, service.onBlock(ctx, wsb, root))
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, root, wsb, postState))
+	require.NoError(t, service.postBlockProcess(ctx, wsb, root, postState, false))

 	st, err = service.HeadState(ctx)
 	require.NoError(t, err)
--- a/beacon-chain/blockchain/receive_attestation.go
+++ b/beacon-chain/blockchain/receive_attestation.go
@@ -62,7 +62,7 @@ func (s *Service) VerifyLmdFfgConsistency(ctx context.Context, a *ethpb.Attestat
 		return err
 	}
 	if !bytes.Equal(a.Data.Target.Root, r) {
-		return errors.New("FFG and LMD votes are not consistent")
+		return fmt.Errorf("FFG and LMD votes are not consistent, block root: %#x, target root: %#x, canonical target root: %#x", a.Data.BeaconBlockRoot, a.Data.Target.Root, r)
 	}
 	return nil
 }
@@ -86,23 +86,30 @@ func (s *Service) spawnProcessAttestationsRoutine() {
 			}
 			log.Warn("Genesis time received, now available to process attestations")
 		}
+		// Wait for node to be synced before running the routine.
+		if err := s.waitForSync(); err != nil {
+			log.WithError(err).Error("Could not wait to sync")
+			return
+		}

-		st := slots.NewSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
-		pat := slots.NewSlotTickerWithOffset(s.genesisTime, -reorgLateBlockCountAttestations, params.BeaconConfig().SecondsPerSlot)
+		reorgInterval := time.Second*time.Duration(params.BeaconConfig().SecondsPerSlot) - reorgLateBlockCountAttestations
+		ticker := slots.NewSlotTickerWithIntervals(s.genesisTime, []time.Duration{0, reorgInterval})
 		for {
 			select {
 			case <-s.ctx.Done():
 				return
-			case <-pat.C():
-				s.UpdateHead(s.ctx, s.CurrentSlot()+1)
-			case <-st.C():
-				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")
-				}
-				s.cfg.ForkChoiceStore.Unlock()
+			case slotInterval := <-ticker.C():
+				if slotInterval.Interval > 0 {
+					s.UpdateHead(s.ctx, slotInterval.Slot+1)
+				} else {
+					s.cfg.ForkChoiceStore.Lock()
+					if err := s.cfg.ForkChoiceStore.NewSlot(s.ctx, slotInterval.Slot); err != nil {
+						log.WithError(err).Error("could not process new slot")
+					}
+					s.cfg.ForkChoiceStore.Unlock()

-				s.UpdateHead(s.ctx, s.CurrentSlot())
+					s.UpdateHead(s.ctx, slotInterval.Slot)
+				}
 			}
 		}
 	}()
--- a/beacon-chain/blockchain/receive_attestation_test.go
+++ b/beacon-chain/blockchain/receive_attestation_test.go
@@ -128,7 +128,13 @@ func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
 	require.NoError(t, err)
 	wsb, err := blocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
-	require.NoError(t, service.onBlock(ctx, wsb, tRoot))
+
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, tRoot, wsb, postState))
+	require.NoError(t, service.postBlockProcess(ctx, wsb, tRoot, postState, false))
 	copied, err = service.cfg.StateGen.StateByRoot(ctx, tRoot)
 	require.NoError(t, err)
 	require.Equal(t, 2, fcs.NodeCount())
@@ -178,7 +184,13 @@ func TestService_UpdateHead_NoAtts(t *testing.T) {
 	require.NoError(t, err)
 	wsb, err := blocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
-	require.NoError(t, service.onBlock(ctx, wsb, tRoot))
+
+	preState, err := service.getBlockPreState(ctx, wsb.Block())
+	require.NoError(t, err)
+	postState, err := service.validateStateTransition(ctx, preState, wsb)
+	require.NoError(t, err)
+	require.NoError(t, service.savePostStateInfo(ctx, tRoot, wsb, postState))
+	require.NoError(t, service.postBlockProcess(ctx, wsb, tRoot, postState, false))
 	require.Equal(t, 2, fcs.NodeCount())
 	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wsb))
 	require.Equal(t, tRoot, service.head.root)
--- a/beacon-chain/blockchain/receive_block.go
+++ b/beacon-chain/blockchain/receive_block.go
@@ -7,15 +7,23 @@ import (
 	"github.com/pkg/errors"
 	"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/state"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
 	"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"
+	ethpbv1 "github.com/prysmaticlabs/prysm/v4/proto/eth/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1/attestation"
 	"github.com/prysmaticlabs/prysm/v4/runtime/version"
 	"github.com/prysmaticlabs/prysm/v4/time"
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 	"go.opencensus.io/trace"
+	"golang.org/x/sync/errgroup"
 )

 // This defines how many epochs since finality the run time will begin to save hot state on to the DB.
@@ -47,14 +55,83 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 		return err
 	}

+	preState, err := s.getBlockPreState(ctx, blockCopy.Block())
+	if err != nil {
+		return errors.Wrap(err, "could not get block's prestate")
+	}
+	// Save current justified and finalized epochs for future use.
+	currStoreJustifiedEpoch := s.CurrentJustifiedCheckpt().Epoch
+	currStoreFinalizedEpoch := s.FinalizedCheckpt().Epoch
+	currentEpoch := coreTime.CurrentEpoch(preState)
+
+	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
+	if err != nil {
+		return err
+	}
+	eg, _ := errgroup.WithContext(ctx)
+	var postState state.BeaconState
+	eg.Go(func() error {
+		postState, err = s.validateStateTransition(ctx, preState, blockCopy)
+		if err != nil {
+			return errors.Wrap(err, "failed to validate consensus state transition function")
+		}
+		return nil
+	})
+	var isValidPayload bool
+	eg.Go(func() error {
+		isValidPayload, err = s.validateExecutionOnBlock(ctx, preStateVersion, preStateHeader, blockCopy, blockRoot)
+		if err != nil {
+			return errors.Wrap(err, "could not notify the engine of the new payload")
+		}
+		return nil
+	})
+	if err := eg.Wait(); err != nil {
+		return err
+	}
+	// The rest of block processing takes a lock on forkchoice.
 	s.cfg.ForkChoiceStore.Lock()
 	defer s.cfg.ForkChoiceStore.Unlock()
-	// Apply state transition on the new block.
-	if err := s.onBlock(ctx, blockCopy, blockRoot); err != nil {
+	if err := s.savePostStateInfo(ctx, blockRoot, blockCopy, postState); err != nil {
+		return errors.Wrap(err, "could not save post state info")
+	}
+
+	if err := s.postBlockProcess(ctx, blockCopy, blockRoot, postState, isValidPayload); err != nil {
 		err := errors.Wrap(err, "could not process block")
 		tracing.AnnotateError(span, err)
 		return err
 	}
+	if coreTime.CurrentEpoch(postState) > currentEpoch {
+		headSt, err := s.HeadState(ctx)
+		if err != nil {
+			return errors.Wrap(err, "could not get head state")
+		}
+		if err := reportEpochMetrics(ctx, postState, headSt); err != nil {
+			log.WithError(err).Error("could not report epoch metrics")
+		}
+	}
+	if err := s.updateJustificationOnBlock(ctx, preState, postState, currStoreJustifiedEpoch); err != nil {
+		return errors.Wrap(err, "could not update justified checkpoint")
+	}
+
+	newFinalized, err := s.updateFinalizationOnBlock(ctx, preState, postState, currStoreFinalizedEpoch)
+	if err != nil {
+		return errors.Wrap(err, "could not update finalized checkpoint")
+	}
+	// Send finalized events and finalized deposits in the background
+	if newFinalized {
+		finalized := s.cfg.ForkChoiceStore.FinalizedCheckpoint()
+		go s.sendNewFinalizedEvent(blockCopy, postState)
+		depCtx, cancel := context.WithTimeout(context.Background(), depositDeadline)
+		go func() {
+			s.insertFinalizedDeposits(depCtx, finalized.Root)
+			cancel()
+		}()
+	}
+
+	// If slasher is configured, forward the attestations in the block via an event feed for processing.
+	if features.Get().EnableSlasher {
+		go s.sendBlockAttestationsToSlasher(blockCopy, preState)
+	}

 	// Handle post block operations such as pruning exits and bls messages if incoming block is the head
 	if err := s.prunePostBlockOperationPools(ctx, blockCopy, blockRoot); err != nil {
@@ -86,6 +163,8 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 		log.WithError(err).Error("Unable to log state transition data")
 	}

+	chainServiceProcessingTime.Observe(float64(time.Since(receivedTime).Milliseconds()))
+
 	return nil
 }

@@ -106,6 +185,13 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []interfaces.Rea
 		return err
 	}

+	lastBR := blkRoots[len(blkRoots)-1]
+	optimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(lastBR)
+	if err != nil {
+		lastSlot := blocks[len(blocks)-1].Block().Slot()
+		log.WithError(err).Errorf("Could not check if block is optimistic, Root: %#x, Slot: %d", lastBR, lastSlot)
+		optimistic = true
+	}
 	for i, b := range blocks {
 		blockCopy, err := b.Copy()
 		if err != nil {
@@ -119,6 +205,7 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []interfaces.Rea
 				BlockRoot:   blkRoots[i],
 				SignedBlock: blockCopy,
 				Verified:    true,
+				Optimistic:  optimistic,
 			},
 		})

@@ -226,3 +313,109 @@ func (s *Service) checkSaveHotStateDB(ctx context.Context) error {

 	return s.cfg.StateGen.DisableSaveHotStateToDB(ctx)
 }
+
+// This performs the state transition function and returns the poststate or an
+// error if the block fails to verify the consensus rules
+func (s *Service) validateStateTransition(ctx context.Context, preState state.BeaconState, signed interfaces.ReadOnlySignedBeaconBlock) (state.BeaconState, error) {
+	b := signed.Block()
+	// Verify that the parent block is in forkchoice
+	parentRoot := b.ParentRoot()
+	if !s.InForkchoice(parentRoot) {
+		return nil, ErrNotDescendantOfFinalized
+	}
+	stateTransitionStartTime := time.Now()
+	postState, err := transition.ExecuteStateTransition(ctx, preState, signed)
+	if err != nil {
+		return nil, invalidBlock{error: err}
+	}
+	stateTransitionProcessingTime.Observe(float64(time.Since(stateTransitionStartTime).Milliseconds()))
+	return postState, nil
+}
+
+// updateJustificationOnBlock updates the justified checkpoint on DB if the
+// incoming block has updated it on forkchoice.
+func (s *Service) updateJustificationOnBlock(ctx context.Context, preState, postState state.BeaconState, preJustifiedEpoch primitives.Epoch) error {
+	justified := s.cfg.ForkChoiceStore.JustifiedCheckpoint()
+	preStateJustifiedEpoch := preState.CurrentJustifiedCheckpoint().Epoch
+	postStateJustifiedEpoch := postState.CurrentJustifiedCheckpoint().Epoch
+	if justified.Epoch > preJustifiedEpoch || (justified.Epoch == postStateJustifiedEpoch && justified.Epoch > preStateJustifiedEpoch) {
+		if err := s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{
+			Epoch: justified.Epoch, Root: justified.Root[:],
+		}); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// updateFinalizationOnBlock performs some duties when the incoming block
+// changes the finalized checkpoint. It returns true when this has happened.
+func (s *Service) updateFinalizationOnBlock(ctx context.Context, preState, postState state.BeaconState, preFinalizedEpoch primitives.Epoch) (bool, error) {
+	preStateFinalizedEpoch := preState.FinalizedCheckpoint().Epoch
+	postStateFinalizedEpoch := postState.FinalizedCheckpoint().Epoch
+	finalized := s.cfg.ForkChoiceStore.FinalizedCheckpoint()
+	if finalized.Epoch > preFinalizedEpoch || (finalized.Epoch == postStateFinalizedEpoch && finalized.Epoch > preStateFinalizedEpoch) {
+		if err := s.updateFinalized(ctx, &ethpb.Checkpoint{Epoch: finalized.Epoch, Root: finalized.Root[:]}); err != nil {
+			return true, err
+		}
+		return true, nil
+	}
+	return false, nil
+}
+
+// sendNewFinalizedEvent sends a new finalization checkpoint event over the
+// event feed. It needs to be called on the background
+func (s *Service) sendNewFinalizedEvent(signed interfaces.ReadOnlySignedBeaconBlock, postState state.BeaconState) {
+	isValidPayload := false
+	s.headLock.RLock()
+	if s.head != nil {
+		isValidPayload = s.head.optimistic
+	}
+	s.headLock.RUnlock()
+
+	// Send an event regarding the new finalized checkpoint over a common event feed.
+	stateRoot := signed.Block().StateRoot()
+	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+		Type: statefeed.FinalizedCheckpoint,
+		Data: &ethpbv1.EventFinalizedCheckpoint{
+			Epoch:               postState.FinalizedCheckpoint().Epoch,
+			Block:               postState.FinalizedCheckpoint().Root,
+			State:               stateRoot[:],
+			ExecutionOptimistic: isValidPayload,
+		},
+	})
+}
+
+// sendBlockAttestationsToSlasher sends the incoming block's attestation to the slasher
+func (s *Service) sendBlockAttestationsToSlasher(signed interfaces.ReadOnlySignedBeaconBlock, preState state.BeaconState) {
+	// Feed the indexed attestation to slasher if enabled. This action
+	// is done in the background to avoid adding more load to this critical code path.
+	ctx := context.TODO()
+	for _, att := range signed.Block().Body().Attestations() {
+		committee, err := helpers.BeaconCommitteeFromState(ctx, preState, att.Data.Slot, att.Data.CommitteeIndex)
+		if err != nil {
+			log.WithError(err).Error("Could not get attestation committee")
+			return
+		}
+		indexedAtt, err := attestation.ConvertToIndexed(ctx, att, committee)
+		if err != nil {
+			log.WithError(err).Error("Could not convert to indexed attestation")
+			return
+		}
+		s.cfg.SlasherAttestationsFeed.Send(indexedAtt)
+	}
+}
+
+// validateExecutionOnBlock notifies the engine of the incoming block execution payload and returns true if the payload is valid
+func (s *Service) validateExecutionOnBlock(ctx context.Context, ver int, header interfaces.ExecutionData, signed interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte) (bool, error) {
+	isValidPayload, err := s.notifyNewPayload(ctx, ver, header, signed)
+	if err != nil {
+		return false, s.handleInvalidExecutionError(ctx, err, blockRoot, signed.Block().ParentRoot())
+	}
+	if signed.Version() < version.Capella && isValidPayload {
+		if err := s.validateMergeTransitionBlock(ctx, ver, header, signed); err != nil {
+			return isValidPayload, err
+		}
+	}
+	return isValidPayload, nil
+}
--- 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"
@@ -34,7 +35,6 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	prysmTime "github.com/prysmaticlabs/prysm/v4/time"
@@ -45,21 +45,21 @@ import (
 // Service represents a service that handles the internal
 // logic of managing the full PoS beacon chain.
 type Service struct {
-	cfg                   *config
-	ctx                   context.Context
-	cancel                context.CancelFunc
-	genesisTime           time.Time
-	head                  *head
-	headLock              sync.RWMutex
-	originBlockRoot       [32]byte // genesis root, or weak subjectivity checkpoint root, depending on how the node is initialized
-	nextEpochBoundarySlot primitives.Slot
-	boundaryRoots         [][32]byte
-	checkpointStateCache  *cache.CheckpointStateCache
-	initSyncBlocks        map[[32]byte]interfaces.ReadOnlySignedBeaconBlock
-	initSyncBlocksLock    sync.RWMutex
-	wsVerifier            *WeakSubjectivityVerifier
-	clockSetter           startup.ClockSetter
-	clockWaiter           startup.ClockWaiter
+	cfg                  *config
+	ctx                  context.Context
+	cancel               context.CancelFunc
+	genesisTime          time.Time
+	head                 *head
+	headLock             sync.RWMutex
+	originBlockRoot      [32]byte // genesis root, or weak subjectivity checkpoint root, depending on how the node is initialized
+	boundaryRoots        [][32]byte
+	checkpointStateCache *cache.CheckpointStateCache
+	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.
@@ -130,7 +130,7 @@ func (s *Service) Start() {
 		}
 	}
 	s.spawnProcessAttestationsRoutine()
-	s.spawnLateBlockTasksLoop()
+	go s.runLateBlockTasks()
 }

 // Stop the blockchain service's main event loop and associated goroutines.
@@ -307,7 +307,13 @@ 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")
 	}

@@ -401,7 +407,7 @@ 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 +445,13 @@ 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
@@ -357,7 +357,7 @@ func TestChainService_SaveHeadNoDB(t *testing.T) {
 	require.NoError(t, s.cfg.StateGen.SaveState(ctx, r, newState))
 	wsb, err := consensusblocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
-	require.NoError(t, s.saveHeadNoDB(ctx, wsb, r, newState))
+	require.NoError(t, s.saveHeadNoDB(ctx, wsb, r, newState, false))

 	newB, err := s.cfg.BeaconDB.HeadBlock(ctx)
 	require.NoError(t, err)
@@ -377,9 +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")
@@ -453,9 +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++ {
--- a/beacon-chain/blockchain/testing/mock.go
+++ b/beacon-chain/blockchain/testing/mock.go
@@ -533,7 +533,7 @@ func (s *ChainService) GetProposerHead() [32]byte {
 	return [32]byte{}
 }

-// SetForkchoiceGenesisTime mocks the same method in the chain service
+// SetForkChoiceGenesisTime mocks the same method in the chain service
 func (s *ChainService) SetForkChoiceGenesisTime(timestamp uint64) {
 	if s.ForkChoiceStore != nil {
 		s.ForkChoiceStore.SetGenesisTime(timestamp)
--- 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"
@@ -38,6 +39,21 @@ func Test_RegisterValidator(t *testing.T) {
 	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)
--- a/beacon-chain/cache/BUILD.bazel
+++ b/beacon-chain/cache/BUILD.bazel
@@ -34,6 +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",
@@ -87,7 +88,6 @@ go_test(
        "//testing/util:go_default_library",
        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
        "@com_github_google_gofuzz//:go_default_library",
-        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )
--- 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/registration.go
+++ b/beacon-chain/cache/registration.go
@@ -3,15 +3,11 @@ package cache
 import (
 	"context"
 	"sync"
-	"time"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v4/math"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
-	log "github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

@@ -38,33 +34,10 @@ func (regCache *RegistrationCache) RegistrationByIndex(id primitives.ValidatorIn
 		regCache.lock.RUnlock()
 		return nil, errors.Wrapf(ErrNotFoundRegistration, "validator id %d", id)
 	}
-	isExpired, err := RegistrationTimeStampExpired(v.Timestamp)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to check registration expiration")
-	}
-	if isExpired {
-		regCache.lock.RUnlock()
-		regCache.lock.Lock()
-		defer regCache.lock.Unlock()
-		delete(regCache.indexToRegistration, id)
-		log.Warnf("registration for validator index %d expired at unix time %d", id, v.Timestamp)
-		return nil, errors.Wrapf(ErrNotFoundRegistration, "validator id %d", id)
-	}
 	regCache.lock.RUnlock()
 	return v, nil
 }

-func RegistrationTimeStampExpired(ts uint64) (bool, error) {
-	// safely convert unint64 to int64
-	i, err := math.Int(ts)
-	if err != nil {
-		return false, err
-	}
-	expiryDuration := params.BeaconConfig().RegistrationDuration
-	// registered time + expiration duration < current time = expired
-	return time.Unix(int64(i), 0).Add(expiryDuration).Before(time.Now()), 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")
--- a/beacon-chain/cache/registration_test.go
+++ b/beacon-chain/cache/registration_test.go
@@ -6,15 +6,12 @@ import (
 	"time"

 	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v4/testing/require"
-	logTest "github.com/sirupsen/logrus/hooks/test"
 )

 func TestRegistrationCache(t *testing.T) {
-	hook := logTest.NewGlobal()
 	pubkey, err := hexutil.Decode("0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
 	require.NoError(t, err)
 	validatorIndex := primitives.ValidatorIndex(1)
@@ -31,29 +28,14 @@ func TestRegistrationCache(t *testing.T) {
 	reg, err := cache.RegistrationByIndex(validatorIndex)
 	require.NoError(t, err)
 	require.Equal(t, string(reg.Pubkey), string(pubkey))
-	t.Run("Registration expired", func(t *testing.T) {
-		validatorIndex2 := primitives.ValidatorIndex(2)
-		overExpirationPadTime := time.Second * time.Duration(params.BeaconConfig().SecondsPerSlot*uint64(params.BeaconConfig().SlotsPerEpoch)*4) // 4 epochs
-		m[validatorIndex2] = &ethpb.ValidatorRegistrationV1{
-			FeeRecipient: []byte{},
-			GasLimit:     100,
-			Timestamp:    uint64(time.Now().Add(-1 * overExpirationPadTime).Unix()),
-			Pubkey:       pubkey,
-		}
-		cache.UpdateIndexToRegisteredMap(context.Background(), m)
-		_, err := cache.RegistrationByIndex(validatorIndex2)
-		require.ErrorContains(t, "no validator registered", err)
-		require.LogsContain(t, hook, "expired")
-	})
-	t.Run("Registration close to expiration still passes", func(t *testing.T) {
+	t.Run("successfully updates", func(t *testing.T) {
 		pubkey, err := hexutil.Decode("0x88247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
 		require.NoError(t, err)
 		validatorIndex2 := primitives.ValidatorIndex(2)
-		overExpirationPadTime := time.Second * time.Duration((params.BeaconConfig().SecondsPerSlot*uint64(params.BeaconConfig().SlotsPerEpoch)*3)-5) // 3 epochs - 5 seconds
 		m[validatorIndex2] = &ethpb.ValidatorRegistrationV1{
 			FeeRecipient: []byte{},
 			GasLimit:     100,
-			Timestamp:    uint64(time.Now().Add(-1 * overExpirationPadTime).Unix()),
+			Timestamp:    uint64(time.Now().Unix()),
 			Pubkey:       pubkey,
 		}
 		cache.UpdateIndexToRegisteredMap(context.Background(), m)
@@ -62,21 +44,3 @@ func TestRegistrationCache(t *testing.T) {
 		require.Equal(t, string(reg.Pubkey), string(pubkey))
 	})
 }
-
-func Test_RegistrationTimeStampExpired(t *testing.T) {
-	// expiration set at 3 epochs
-	t.Run("expired registration", func(t *testing.T) {
-		overExpirationPadTime := time.Second * time.Duration(params.BeaconConfig().SecondsPerSlot*uint64(params.BeaconConfig().SlotsPerEpoch)*4) // 4 epochs
-		ts := uint64(time.Now().Add(-1 * overExpirationPadTime).Unix())
-		isExpired, err := RegistrationTimeStampExpired(ts)
-		require.NoError(t, err)
-		require.Equal(t, true, isExpired)
-	})
-	t.Run("is not expired registration", func(t *testing.T) {
-		overExpirationPadTime := time.Second * time.Duration((params.BeaconConfig().SecondsPerSlot*uint64(params.BeaconConfig().SlotsPerEpoch)*3)-5) // 3 epochs -5 seconds
-		ts := uint64(time.Now().Add(-1 * overExpirationPadTime).Unix())
-		isExpired, err := RegistrationTimeStampExpired(ts)
-		require.NoError(t, err)
-		require.Equal(t, false, isExpired)
-	})
-}
--- 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")
@@ -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/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
@@ -190,6 +195,7 @@ func IsSyncCommitteeAggregator(sig []byte) (bool, error) {
 }

 // ValidateSyncMessageTime validates sync message to ensure that the provided slot is valid.
+// Spec: [IGNORE] The message's slot is for the current slot (with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance), i.e. sync_committee_message.slot == current_slot
 func ValidateSyncMessageTime(slot primitives.Slot, genesisTime time.Time, clockDisparity time.Duration) error {
 	if err := slots.ValidateClock(slot, uint64(genesisTime.Unix())); err != nil {
 		return err
@@ -217,15 +223,19 @@ 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(
-			"sync message time %v (slot %d) not within allowable range of %v (slot %d) to %v (slot %d)",
+		syncErr := fmt.Errorf(
+			"sync message time %v (message slot %d) not within allowable range of %v to %v (current slot %d)",
 			messageTime,
 			slot,
 			lowerBound,
-			uint64(lowerBound.Unix()-genesisTime.Unix())/params.BeaconConfig().SecondsPerSlot,
 			upperBound,
-			uint64(upperBound.Unix()-genesisTime.Unix())/params.BeaconConfig().SecondsPerSlot,
+			currentSlot,
 		)
+		// 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/altair/sync_committee_test.go
+++ b/beacon-chain/core/altair/sync_committee_test.go
@@ -311,7 +311,7 @@ func Test_ValidateSyncMessageTime(t *testing.T) {
 				syncMessageSlot: 16,
 				genesisTime:     prysmTime.Now().Add(-(15 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)),
 			},
-			wantedErr: "(slot 16) not within allowable range of",
+			wantedErr: "(message slot 16) not within allowable range of",
 		},
 		{
 			name: "sync_message.slot == current_slot+CLOCK_DISPARITY",
@@ -327,7 +327,7 @@ func Test_ValidateSyncMessageTime(t *testing.T) {
 				syncMessageSlot: 100,
 				genesisTime:     prysmTime.Now().Add(-(100 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second) + params.BeaconNetworkConfig().MaximumGossipClockDisparity + 1000*time.Millisecond),
 			},
-			wantedErr: "(slot 100) not within allowable range of",
+			wantedErr: "(message slot 100) not within allowable range of",
 		},
 		{
 			name: "sync_message.slot == current_slot-CLOCK_DISPARITY",
@@ -343,7 +343,7 @@ func Test_ValidateSyncMessageTime(t *testing.T) {
 				syncMessageSlot: 101,
 				genesisTime:     prysmTime.Now().Add(-(100*time.Duration(params.BeaconConfig().SecondsPerSlot)*time.Second + params.BeaconNetworkConfig().MaximumGossipClockDisparity)),
 			},
-			wantedErr: "(slot 101) not within allowable range of",
+			wantedErr: "(message slot 101) not within allowable range of",
 		},
 		{
 			name: "sync_message.slot is well beyond current slot",
--- a/beacon-chain/core/blocks/exit.go
+++ b/beacon-chain/core/blocks/exit.go
@@ -50,6 +50,8 @@ func ProcessVoluntaryExits(
 	beaconState state.BeaconState,
 	exits []*ethpb.SignedVoluntaryExit,
 ) (state.BeaconState, error) {
+	maxExitEpoch, churn := v.ValidatorsMaxExitEpochAndChurn(beaconState)
+	var exitEpoch primitives.Epoch
 	for idx, exit := range exits {
 		if exit == nil || exit.Exit == nil {
 			return nil, errors.New("nil voluntary exit in block body")
@@ -61,8 +63,15 @@ func ProcessVoluntaryExits(
 		if err := VerifyExitAndSignature(val, beaconState.Slot(), beaconState.Fork(), exit, beaconState.GenesisValidatorsRoot()); err != nil {
 			return nil, errors.Wrapf(err, "could not verify exit %d", idx)
 		}
-		beaconState, err = v.InitiateValidatorExit(ctx, beaconState, exit.Exit.ValidatorIndex)
-		if err != nil {
+		beaconState, exitEpoch, err = v.InitiateValidatorExit(ctx, beaconState, exit.Exit.ValidatorIndex, maxExitEpoch, churn)
+		if err == nil {
+			if exitEpoch > maxExitEpoch {
+				maxExitEpoch = exitEpoch
+				churn = 1
+			} else if exitEpoch == maxExitEpoch {
+				churn++
+			}
+		} else if !errors.Is(err, v.ValidatorAlreadyExitedErr) {
 			return nil, err
 		}
 	}
--- a/beacon-chain/core/blocks/payload.go
+++ b/beacon-chain/core/blocks/payload.go
@@ -61,7 +61,7 @@ func IsExecutionBlock(body interfaces.ReadOnlyBeaconBlockBody) (bool, error) {
 	}
 	payload, err := body.Execution()
 	switch {
-	case errors.Is(err, consensus_types.ErrUnsupportedGetter):
+	case errors.Is(err, consensus_types.ErrUnsupportedField):
 		return false, nil
 	case err != nil:
 		return false, err
--- a/beacon-chain/core/epoch/epoch_processing.go
+++ b/beacon-chain/core/epoch/epoch_processing.go
@@ -110,8 +110,11 @@ func ProcessRegistryUpdates(ctx context.Context, state state.BeaconState) (state
 		isActive := helpers.IsActiveValidator(validator, currentEpoch)
 		belowEjectionBalance := validator.EffectiveBalance <= ejectionBal
 		if isActive && belowEjectionBalance {
-			state, err = validators.InitiateValidatorExit(ctx, state, primitives.ValidatorIndex(idx))
-			if err != nil {
+			// Here is fine to do a quadratic loop since this should
+			// barely happen
+			maxExitEpoch, churn := validators.ValidatorsMaxExitEpochAndChurn(state)
+			state, _, err = validators.InitiateValidatorExit(ctx, state, primitives.ValidatorIndex(idx), maxExitEpoch, churn)
+			if err != nil && !errors.Is(err, validators.ValidatorAlreadyExitedErr) {
 				return nil, errors.Wrapf(err, "could not initiate exit for validator %d", idx)
 			}
 		}
--- a/beacon-chain/core/feed/state/events.go
+++ b/beacon-chain/core/feed/state/events.go
@@ -39,6 +39,8 @@ type BlockProcessedData struct {
 	SignedBlock interfaces.ReadOnlySignedBeaconBlock
 	// Verified is true if the block's BLS contents have been verified.
 	Verified bool
+	// Optimistic is true if the block is optimistic.
+	Optimistic bool
 }

 // ChainStartedData is the data sent with ChainStarted events.
--- 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",
    ],
 )

@@ -68,7 +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 {
@@ -184,7 +168,7 @@ func ValidateAttestationTime(attSlot primitives.Slot, genesisTime time.Time, clo
 	)
 	if attTime.Before(lowerBounds) {
 		attReceivedTooLateCount.Inc()
-		return attError
+		return errors.Join(ErrTooLate, attError)
 	}
 	if attTime.After(upperBounds) {
 		attReceivedTooEarlyCount.Inc()
--- 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
@@ -295,61 +295,58 @@ func ShuffledIndices(s state.ReadOnlyBeaconState, epoch primitives.Epoch) ([]pri
 }

 // UpdateCommitteeCache gets called at the beginning of every epoch to cache the committee shuffled indices
-// list with committee index and epoch number. It caches the shuffled indices for current epoch and next epoch.
-func UpdateCommitteeCache(ctx context.Context, state state.ReadOnlyBeaconState, epoch primitives.Epoch) error {
-	for _, e := range []primitives.Epoch{epoch, epoch + 1} {
-		seed, err := Seed(state, e, params.BeaconConfig().DomainBeaconAttester)
-		if err != nil {
-			return err
-		}
-		if committeeCache.HasEntry(string(seed[:])) {
-			return nil
-		}
-
-		shuffledIndices, err := ShuffledIndices(state, e)
-		if err != nil {
-			return err
-		}
-
-		count := SlotCommitteeCount(uint64(len(shuffledIndices)))
-
-		// Store the sorted indices as well as shuffled indices. In current spec,
-		// sorted indices is required to retrieve proposer index. This is also
-		// used for failing verify signature fallback.
-		sortedIndices := make([]primitives.ValidatorIndex, len(shuffledIndices))
-		copy(sortedIndices, shuffledIndices)
-		sort.Slice(sortedIndices, func(i, j int) bool {
-			return sortedIndices[i] < sortedIndices[j]
-		})
-
-		if err := committeeCache.AddCommitteeShuffledList(ctx, &cache.Committees{
-			ShuffledIndices: shuffledIndices,
-			CommitteeCount:  uint64(params.BeaconConfig().SlotsPerEpoch.Mul(count)),
-			Seed:            seed,
-			SortedIndices:   sortedIndices,
-		}); err != nil {
-			return err
-		}
+// list with committee index and epoch number. It caches the shuffled indices for the input epoch.
+func UpdateCommitteeCache(ctx context.Context, state state.ReadOnlyBeaconState, e primitives.Epoch) error {
+	seed, err := Seed(state, e, params.BeaconConfig().DomainBeaconAttester)
+	if err != nil {
+		return err
+	}
+	if committeeCache.HasEntry(string(seed[:])) {
+		return nil
+	}
+	shuffledIndices, err := ShuffledIndices(state, e)
+	if err != nil {
+		return err
 	}

+	count := SlotCommitteeCount(uint64(len(shuffledIndices)))
+
+	// Store the sorted indices as well as shuffled indices. In current spec,
+	// sorted indices is required to retrieve proposer index. This is also
+	// used for failing verify signature fallback.
+	sortedIndices := make([]primitives.ValidatorIndex, len(shuffledIndices))
+	copy(sortedIndices, shuffledIndices)
+	sort.Slice(sortedIndices, func(i, j int) bool {
+		return sortedIndices[i] < sortedIndices[j]
+	})
+
+	if err := committeeCache.AddCommitteeShuffledList(ctx, &cache.Committees{
+		ShuffledIndices: shuffledIndices,
+		CommitteeCount:  uint64(params.BeaconConfig().SlotsPerEpoch.Mul(count)),
+		Seed:            seed,
+		SortedIndices:   sortedIndices,
+	}); err != nil {
+		return err
+	}
 	return nil
 }

 // 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 +363,11 @@ 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
 	}
@@ -432,11 +429,10 @@ 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
@@ -413,7 +413,7 @@ func TestUpdateCommitteeCache_CanUpdate(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, UpdateCommitteeCache(context.Background(), state, time.CurrentEpoch(state)))

-	epoch := primitives.Epoch(1)
+	epoch := primitives.Epoch(0)
 	idx := primitives.CommitteeIndex(1)
 	seed, err := Seed(state, epoch, params.BeaconConfig().DomainBeaconAttester)
 	require.NoError(t, err)
@@ -423,6 +423,40 @@ func TestUpdateCommitteeCache_CanUpdate(t *testing.T) {
 	assert.Equal(t, params.BeaconConfig().TargetCommitteeSize, uint64(len(indices)), "Did not save correct indices lengths")
 }

+func TestUpdateCommitteeCache_CanUpdateAcrossEpochs(t *testing.T) {
+	ClearCache()
+	defer ClearCache()
+	validatorCount := params.BeaconConfig().MinGenesisActiveValidatorCount
+	validators := make([]*ethpb.Validator, validatorCount)
+	indices := make([]primitives.ValidatorIndex, validatorCount)
+	for i := primitives.ValidatorIndex(0); uint64(i) < validatorCount; i++ {
+		validators[i] = &ethpb.Validator{
+			ExitEpoch:        params.BeaconConfig().FarFutureEpoch,
+			EffectiveBalance: 1,
+		}
+		indices[i] = i
+	}
+	state, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
+		Validators:  validators,
+		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+	})
+	require.NoError(t, err)
+	e := time.CurrentEpoch(state)
+	require.NoError(t, UpdateCommitteeCache(context.Background(), state, e))
+
+	seed, err := Seed(state, e, params.BeaconConfig().DomainBeaconAttester)
+	require.NoError(t, err)
+	require.Equal(t, true, committeeCache.HasEntry(string(seed[:])))
+
+	nextSeed, err := Seed(state, e+1, params.BeaconConfig().DomainBeaconAttester)
+	require.NoError(t, err)
+	require.Equal(t, false, committeeCache.HasEntry(string(nextSeed[:])))
+
+	require.NoError(t, UpdateCommitteeCache(context.Background(), state, e+1))
+
+	require.Equal(t, true, committeeCache.HasEntry(string(nextSeed[:])))
+}
+
 func BenchmarkComputeCommittee300000_WithPreCache(b *testing.B) {
 	validators := make([]*ethpb.Validator, 300000)
 	for i := 0; i < len(validators); i++ {
@@ -639,7 +673,7 @@ 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/shuffle.go
+++ b/beacon-chain/core/helpers/shuffle.go
@@ -184,7 +184,7 @@ func innerShuffleList(input []primitives.ValidatorIndex, seed [32]byte, shuffle
 	for {
 		buf[seedSize] = r
 		ph := hashfunc(buf[:pivotViewSize])
-		pivot := bytesutil.FromBytes8(ph[:8]) % listSize
+		pivot := binary.LittleEndian.Uint64(ph[:8]) % listSize
 		mirror := (pivot + 1) >> 1
 		binary.LittleEndian.PutUint32(buf[pivotViewSize:], uint32(pivot>>8))
 		source := hashfunc(buf)
--- a/beacon-chain/core/helpers/validators.go
+++ b/beacon-chain/core/helpers/validators.go
@@ -17,6 +17,7 @@ import (
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 	log "github.com/sirupsen/logrus"
+	"go.opencensus.io/trace"
 )

 var CommitteeCacheInProgressHit = promauto.NewCounter(prometheus.CounterOpts{
@@ -261,7 +262,7 @@ func BeaconProposerIndex(ctx context.Context, state state.ReadOnlyBeaconState) (
 				}
 				return proposerIndices[state.Slot()%params.BeaconConfig().SlotsPerEpoch], nil
 			}
-			if err := UpdateProposerIndicesInCache(ctx, state); err != nil {
+			if err := UpdateProposerIndicesInCache(ctx, state, time.CurrentEpoch(state)); err != nil {
 				return 0, errors.Wrap(err, "could not update committee cache")
 			}
 		}
@@ -396,3 +397,22 @@ func isEligibleForActivation(activationEligibilityEpoch, activationEpoch, finali
 	return activationEligibilityEpoch <= finalizedEpoch &&
 		activationEpoch == params.BeaconConfig().FarFutureEpoch
 }
+
+// LastActivatedValidatorIndex provides the last activated validator given a state
+func LastActivatedValidatorIndex(ctx context.Context, st state.ReadOnlyBeaconState) (primitives.ValidatorIndex, error) {
+	_, span := trace.StartSpan(ctx, "helpers.LastActivatedValidatorIndex")
+	defer span.End()
+	var lastActivatedvalidatorIndex primitives.ValidatorIndex
+	// linear search because status are not sorted
+	for j := st.NumValidators() - 1; j >= 0; j-- {
+		val, err := st.ValidatorAtIndexReadOnly(primitives.ValidatorIndex(j))
+		if err != nil {
+			return 0, err
+		}
+		if IsActiveValidatorUsingTrie(val, time.CurrentEpoch(st)) {
+			lastActivatedvalidatorIndex = primitives.ValidatorIndex(j)
+			break
+		}
+	}
+	return lastActivatedvalidatorIndex, nil
+}
--- a/beacon-chain/core/helpers/validators_test.go
+++ b/beacon-chain/core/helpers/validators_test.go
@@ -727,3 +727,26 @@ func computeProposerIndexWithValidators(validators []*ethpb.Validator, activeInd
 		}
 	}
 }
+
+func TestLastActivatedValidatorIndex_OK(t *testing.T) {
+	beaconState, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{})
+	require.NoError(t, err)
+
+	validators := make([]*ethpb.Validator, 4)
+	balances := make([]uint64, len(validators))
+	for i := uint64(0); i < 4; i++ {
+		validators[i] = &ethpb.Validator{
+			PublicKey:             make([]byte, params.BeaconConfig().BLSPubkeyLength),
+			WithdrawalCredentials: make([]byte, 32),
+			EffectiveBalance:      32 * 1e9,
+			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
+		}
+		balances[i] = validators[i].EffectiveBalance
+	}
+	require.NoError(t, beaconState.SetValidators(validators))
+	require.NoError(t, beaconState.SetBalances(balances))
+
+	index, err := LastActivatedValidatorIndex(context.Background(), beaconState)
+	require.NoError(t, err)
+	require.Equal(t, index, primitives.ValidatorIndex(3))
+}
--- a/beacon-chain/core/validators/BUILD.bazel
+++ b/beacon-chain/core/validators/BUILD.bazel
@@ -15,7 +15,6 @@ go_library(
        "//beacon-chain/state:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/primitives:go_default_library",
-        "//math:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
        "//time/slots:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
--- a/beacon-chain/core/validators/validator.go
+++ b/beacon-chain/core/validators/validator.go
@@ -13,11 +13,34 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
-	mathutil "github.com/prysmaticlabs/prysm/v4/math"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v4/time/slots"
 )

+// ValidatorAlreadyExitedErr is an error raised when trying to process an exit of
+// an already exited validator
+var ValidatorAlreadyExitedErr = errors.New("validator already exited")
+
+// ValidatorsMaxExitEpochAndChurn returns the maximum non-FAR_FUTURE_EPOCH exit
+// epoch and the number of them
+func ValidatorsMaxExitEpochAndChurn(s state.BeaconState) (maxExitEpoch primitives.Epoch, churn uint64) {
+	farFutureEpoch := params.BeaconConfig().FarFutureEpoch
+	err := s.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
+		e := val.ExitEpoch()
+		if e != farFutureEpoch {
+			if e > maxExitEpoch {
+				maxExitEpoch = e
+				churn = 1
+			} else if e == maxExitEpoch {
+				churn++
+			}
+		}
+		return nil
+	})
+	_ = err
+	return
+}
+
 // InitiateValidatorExit takes in validator index and updates
 // validator with correct voluntary exit parameters.
 //
@@ -42,73 +65,43 @@ import (
 //	  # Set validator exit epoch and withdrawable epoch
 //	  validator.exit_epoch = exit_queue_epoch
 //	  validator.withdrawable_epoch = Epoch(validator.exit_epoch + MIN_VALIDATOR_WITHDRAWABILITY_DELAY)
-func InitiateValidatorExit(ctx context.Context, s state.BeaconState, idx primitives.ValidatorIndex) (state.BeaconState, error) {
+func InitiateValidatorExit(ctx context.Context, s state.BeaconState, idx primitives.ValidatorIndex, exitQueueEpoch primitives.Epoch, churn uint64) (state.BeaconState, primitives.Epoch, error) {
+	exitableEpoch := helpers.ActivationExitEpoch(time.CurrentEpoch(s))
+	if exitableEpoch > exitQueueEpoch {
+		exitQueueEpoch = exitableEpoch
+		churn = 0
+	}
 	validator, err := s.ValidatorAtIndex(idx)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 	if validator.ExitEpoch != params.BeaconConfig().FarFutureEpoch {
-		return s, nil
-	}
-	var exitEpochs []primitives.Epoch
-	err = s.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
-		if val.ExitEpoch() != params.BeaconConfig().FarFutureEpoch {
-			exitEpochs = append(exitEpochs, val.ExitEpoch())
-		}
-		return nil
-	})
-	if err != nil {
-		return nil, err
-	}
-	exitEpochs = append(exitEpochs, helpers.ActivationExitEpoch(time.CurrentEpoch(s)))
-
-	// Obtain the exit queue epoch as the maximum number in the exit epochs array.
-	exitQueueEpoch := primitives.Epoch(0)
-	for _, i := range exitEpochs {
-		if exitQueueEpoch < i {
-			exitQueueEpoch = i
-		}
-	}
-
-	// We use the exit queue churn to determine if we have passed a churn limit.
-	exitQueueChurn := uint64(0)
-	err = s.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
-		if val.ExitEpoch() == exitQueueEpoch {
-			var mErr error
-			exitQueueChurn, mErr = mathutil.Add64(exitQueueChurn, 1)
-			if mErr != nil {
-				return mErr
-			}
-		}
-		return nil
-	})
-	if err != nil {
-		return nil, err
+		return s, validator.ExitEpoch, ValidatorAlreadyExitedErr
 	}
 	activeValidatorCount, err := helpers.ActiveValidatorCount(ctx, s, time.CurrentEpoch(s))
 	if err != nil {
-		return nil, errors.Wrap(err, "could not get active validator count")
+		return nil, 0, errors.Wrap(err, "could not get active validator count")
 	}
-	churn, err := helpers.ValidatorChurnLimit(activeValidatorCount)
+	currentChurn, err := helpers.ValidatorChurnLimit(activeValidatorCount)
 	if err != nil {
-		return nil, errors.Wrap(err, "could not get churn limit")
+		return nil, 0, errors.Wrap(err, "could not get churn limit")
 	}

-	if exitQueueChurn >= churn {
+	if churn >= currentChurn {
 		exitQueueEpoch, err = exitQueueEpoch.SafeAdd(1)
 		if err != nil {
-			return nil, err
+			return nil, 0, err
 		}
 	}
 	validator.ExitEpoch = exitQueueEpoch
 	validator.WithdrawableEpoch, err = exitQueueEpoch.SafeAddEpoch(params.BeaconConfig().MinValidatorWithdrawabilityDelay)
 	if err != nil {
-		return nil, err
+		return nil, 0, err
 	}
 	if err := s.UpdateValidatorAtIndex(idx, validator); err != nil {
-		return nil, err
+		return nil, 0, err
 	}
-	return s, nil
+	return s, exitQueueEpoch, nil
 }

 // SlashValidator slashes the malicious validator's balance and awards
@@ -144,8 +137,9 @@ func SlashValidator(
 	slashedIdx primitives.ValidatorIndex,
 	penaltyQuotient uint64,
 	proposerRewardQuotient uint64) (state.BeaconState, error) {
-	s, err := InitiateValidatorExit(ctx, s, slashedIdx)
-	if err != nil {
+	maxExitEpoch, churn := ValidatorsMaxExitEpochAndChurn(s)
+	s, _, err := InitiateValidatorExit(ctx, s, slashedIdx, maxExitEpoch, churn)
+	if err != nil && !errors.Is(err, ValidatorAlreadyExitedErr) {
 		return nil, errors.Wrapf(err, "could not initiate validator %d exit", slashedIdx)
 	}
 	currentEpoch := slots.ToEpoch(s.Slot())
--- a/beacon-chain/core/validators/validator_test.go
+++ b/beacon-chain/core/validators/validator_test.go
@@ -48,8 +48,9 @@ func TestInitiateValidatorExit_AlreadyExited(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	newState, err := InitiateValidatorExit(context.Background(), state, 0)
-	require.NoError(t, err)
+	newState, epoch, err := InitiateValidatorExit(context.Background(), state, 0, 199, 1)
+	require.ErrorIs(t, err, ValidatorAlreadyExitedErr)
+	require.Equal(t, exitEpoch, epoch)
 	v, err := newState.ValidatorAtIndex(0)
 	require.NoError(t, err)
 	assert.Equal(t, exitEpoch, v.ExitEpoch, "Already exited")
@@ -66,8 +67,9 @@ func TestInitiateValidatorExit_ProperExit(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	newState, err := InitiateValidatorExit(context.Background(), state, idx)
+	newState, epoch, err := InitiateValidatorExit(context.Background(), state, idx, exitedEpoch+2, 1)
 	require.NoError(t, err)
+	require.Equal(t, exitedEpoch+2, epoch)
 	v, err := newState.ValidatorAtIndex(idx)
 	require.NoError(t, err)
 	assert.Equal(t, exitedEpoch+2, v.ExitEpoch, "Exit epoch was not the highest")
@@ -85,8 +87,9 @@ func TestInitiateValidatorExit_ChurnOverflow(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	newState, err := InitiateValidatorExit(context.Background(), state, idx)
+	newState, epoch, err := InitiateValidatorExit(context.Background(), state, idx, exitedEpoch+2, 4)
 	require.NoError(t, err)
+	require.Equal(t, exitedEpoch+3, epoch)

 	// Because of exit queue overflow,
 	// validator who init exited has to wait one more epoch.
@@ -106,7 +109,7 @@ func TestInitiateValidatorExit_WithdrawalOverflows(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	_, err = InitiateValidatorExit(context.Background(), state, 1)
+	_, _, err = InitiateValidatorExit(context.Background(), state, 1, params.BeaconConfig().FarFutureEpoch-1, 1)
 	require.ErrorContains(t, "addition overflows", err)
 }

@@ -337,3 +340,78 @@ func TestExitedValidatorIndices(t *testing.T) {
 		assert.DeepEqual(t, tt.wanted, exitedIndices)
 	}
 }
+
+func TestValidatorMaxExitEpochAndChurn(t *testing.T) {
+	tests := []struct {
+		state       *ethpb.BeaconState
+		wantedEpoch primitives.Epoch
+		wantedChurn uint64
+	}{
+		{
+			state: &ethpb.BeaconState{
+				Validators: []*ethpb.Validator{
+					{
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
+						ExitEpoch:         0,
+						WithdrawableEpoch: params.BeaconConfig().MinValidatorWithdrawabilityDelay,
+					},
+					{
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
+						ExitEpoch:         0,
+						WithdrawableEpoch: 10,
+					},
+					{
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
+						ExitEpoch:         0,
+						WithdrawableEpoch: params.BeaconConfig().MinValidatorWithdrawabilityDelay,
+					},
+				},
+			},
+			wantedEpoch: 0,
+			wantedChurn: 3,
+		},
+		{
+			state: &ethpb.BeaconState{
+				Validators: []*ethpb.Validator{
+					{
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
+						ExitEpoch:         params.BeaconConfig().FarFutureEpoch,
+						WithdrawableEpoch: params.BeaconConfig().MinValidatorWithdrawabilityDelay,
+					},
+				},
+			},
+			wantedEpoch: 0,
+			wantedChurn: 0,
+		},
+		{
+			state: &ethpb.BeaconState{
+				Validators: []*ethpb.Validator{
+					{
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
+						ExitEpoch:         1,
+						WithdrawableEpoch: params.BeaconConfig().MinValidatorWithdrawabilityDelay,
+					},
+					{
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
+						ExitEpoch:         0,
+						WithdrawableEpoch: 10,
+					},
+					{
+						EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
+						ExitEpoch:         1,
+						WithdrawableEpoch: params.BeaconConfig().MinValidatorWithdrawabilityDelay,
+					},
+				},
+			},
+			wantedEpoch: 1,
+			wantedChurn: 2,
+		},
+	}
+	for _, tt := range tests {
+		s, err := state_native.InitializeFromProtoPhase0(tt.state)
+		require.NoError(t, err)
+		epoch, churn := ValidatorsMaxExitEpochAndChurn(s)
+		require.Equal(t, tt.wantedEpoch, epoch)
+		require.Equal(t, tt.wantedChurn, churn)
+	}
+}
--- a/beacon-chain/db/kv/migration_state_validators.go
+++ b/beacon-chain/db/kv/migration_state_validators.go
@@ -130,9 +130,15 @@ func performValidatorStateMigration(ctx context.Context, bar *progressbar.Progre
 				return err
 			}
 			item := enc
-			if hasAltairKey(item) {
+			switch {
+			case hasAltairKey(enc):
 				item = item[len(altairKey):]
+			case hasBellatrixKey(enc):
+				item = item[len(bellatrixKey):]
+			case hasCapellaKey(enc):
+				item = item[len(capellaKey):]
 			}
+
 			detector, err := detect.FromState(item)
 			if err != nil {
 				return err
@@ -165,9 +171,14 @@ func performValidatorStateMigration(ctx context.Context, bar *progressbar.Progre
 				return err
 			}
 			var stateBytes []byte
-			if hasAltairKey(enc) {
+			switch {
+			case hasAltairKey(enc):
 				stateBytes = snappy.Encode(nil, append(altairKey, rawObj...))
-			} else {
+			case hasBellatrixKey(enc):
+				stateBytes = snappy.Encode(nil, append(bellatrixKey, rawObj...))
+			case hasCapellaKey(enc):
+				stateBytes = snappy.Encode(nil, append(capellaKey, rawObj...))
+			default:
 				stateBytes = snappy.Encode(nil, rawObj)
 			}
 			if stateErr := stateBkt.Put(keys[index], stateBytes); stateErr != nil {
--- a/beacon-chain/db/kv/migration_state_validators_test.go
+++ b/beacon-chain/db/kv/migration_state_validators_test.go
@@ -313,3 +313,217 @@ func Test_migrateAltairStateValidators(t *testing.T) {
 		})
 	}
 }
+
+func Test_migrateBellatrixStateValidators(t *testing.T) {
+	tests := []struct {
+		name  string
+		setup func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator)
+		eval  func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator)
+	}{
+		{
+			name: "migrates validators and adds them to new buckets",
+			setup: func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator) {
+				// create some new buckets that should be present for this migration
+				err := dbStore.db.Update(func(tx *bbolt.Tx) error {
+					_, err := tx.CreateBucketIfNotExists(stateValidatorsBucket)
+					assert.NoError(t, err)
+					_, err = tx.CreateBucketIfNotExists(blockRootValidatorHashesBucket)
+					assert.NoError(t, err)
+					return nil
+				})
+				assert.NoError(t, err)
+			},
+			eval: func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator) {
+				// check whether the new buckets are present
+				err := dbStore.db.View(func(tx *bbolt.Tx) error {
+					valBkt := tx.Bucket(stateValidatorsBucket)
+					assert.NotNil(t, valBkt)
+					idxBkt := tx.Bucket(blockRootValidatorHashesBucket)
+					assert.NotNil(t, idxBkt)
+					return nil
+				})
+				assert.NoError(t, err)
+
+				// check if the migration worked
+				blockRoot := [32]byte{'A'}
+				rcvdState, err := dbStore.State(context.Background(), blockRoot)
+				assert.NoError(t, err)
+				require.DeepSSZEqual(t, rcvdState.ToProtoUnsafe(), state.ToProtoUnsafe(), "saved state with validators and retrieved state are not matching")
+
+				// find hashes of the validators that are set as part of the state
+				var hashes []byte
+				var individualHashes [][]byte
+				for _, val := range vals {
+					hash, hashErr := val.HashTreeRoot()
+					assert.NoError(t, hashErr)
+					hashes = append(hashes, hash[:]...)
+					individualHashes = append(individualHashes, hash[:])
+				}
+
+				// check if all the validators that were in the state, are stored properly in the validator bucket
+				pbState, err := state_native.ProtobufBeaconStateBellatrix(rcvdState.ToProtoUnsafe())
+				assert.NoError(t, err)
+				validatorsFoundCount := 0
+				for _, val := range pbState.Validators {
+					hash, hashErr := val.HashTreeRoot()
+					assert.NoError(t, hashErr)
+					found := false
+					for _, h := range individualHashes {
+						if bytes.Equal(hash[:], h) {
+							found = true
+						}
+					}
+					require.Equal(t, true, found)
+					validatorsFoundCount++
+				}
+				require.Equal(t, len(vals), validatorsFoundCount)
+
+				// check if the state validator indexes are stored properly
+				err = dbStore.db.View(func(tx *bbolt.Tx) error {
+					rcvdValhashBytes := tx.Bucket(blockRootValidatorHashesBucket).Get(blockRoot[:])
+					rcvdValHashes, sErr := snappy.Decode(nil, rcvdValhashBytes)
+					assert.NoError(t, sErr)
+					require.DeepEqual(t, hashes, rcvdValHashes)
+					return nil
+				})
+				assert.NoError(t, err)
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dbStore := setupDB(t)
+
+			// add a state with the given validators
+			vals := validators(10)
+			blockRoot := [32]byte{'A'}
+			st, _ := util.DeterministicGenesisStateBellatrix(t, 20)
+			err := st.SetFork(&v1alpha1.Fork{
+				PreviousVersion: params.BeaconConfig().AltairForkVersion,
+				CurrentVersion:  params.BeaconConfig().BellatrixForkVersion,
+				Epoch:           0,
+			})
+			require.NoError(t, err)
+			assert.NoError(t, st.SetSlot(100))
+			assert.NoError(t, st.SetValidators(vals))
+			assert.NoError(t, dbStore.SaveState(context.Background(), st, blockRoot))
+
+			// enable historical state representation flag to test this
+			resetCfg := features.InitWithReset(&features.Flags{
+				EnableHistoricalSpaceRepresentation: true,
+			})
+			defer resetCfg()
+
+			tt.setup(t, dbStore, st, vals)
+			assert.NoError(t, migrateStateValidators(context.Background(), dbStore.db), "migrateArchivedIndex(tx) error")
+			tt.eval(t, dbStore, st, vals)
+		})
+	}
+}
+
+func Test_migrateCapellaStateValidators(t *testing.T) {
+	tests := []struct {
+		name  string
+		setup func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator)
+		eval  func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator)
+	}{
+		{
+			name: "migrates validators and adds them to new buckets",
+			setup: func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator) {
+				// create some new buckets that should be present for this migration
+				err := dbStore.db.Update(func(tx *bbolt.Tx) error {
+					_, err := tx.CreateBucketIfNotExists(stateValidatorsBucket)
+					assert.NoError(t, err)
+					_, err = tx.CreateBucketIfNotExists(blockRootValidatorHashesBucket)
+					assert.NoError(t, err)
+					return nil
+				})
+				assert.NoError(t, err)
+			},
+			eval: func(t *testing.T, dbStore *Store, state state.BeaconState, vals []*v1alpha1.Validator) {
+				// check whether the new buckets are present
+				err := dbStore.db.View(func(tx *bbolt.Tx) error {
+					valBkt := tx.Bucket(stateValidatorsBucket)
+					assert.NotNil(t, valBkt)
+					idxBkt := tx.Bucket(blockRootValidatorHashesBucket)
+					assert.NotNil(t, idxBkt)
+					return nil
+				})
+				assert.NoError(t, err)
+
+				// check if the migration worked
+				blockRoot := [32]byte{'A'}
+				rcvdState, err := dbStore.State(context.Background(), blockRoot)
+				assert.NoError(t, err)
+				require.DeepSSZEqual(t, rcvdState.ToProtoUnsafe(), state.ToProtoUnsafe(), "saved state with validators and retrieved state are not matching")
+
+				// find hashes of the validators that are set as part of the state
+				var hashes []byte
+				var individualHashes [][]byte
+				for _, val := range vals {
+					hash, hashErr := val.HashTreeRoot()
+					assert.NoError(t, hashErr)
+					hashes = append(hashes, hash[:]...)
+					individualHashes = append(individualHashes, hash[:])
+				}
+
+				// check if all the validators that were in the state, are stored properly in the validator bucket
+				pbState, err := state_native.ProtobufBeaconStateCapella(rcvdState.ToProtoUnsafe())
+				assert.NoError(t, err)
+				validatorsFoundCount := 0
+				for _, val := range pbState.Validators {
+					hash, hashErr := val.HashTreeRoot()
+					assert.NoError(t, hashErr)
+					found := false
+					for _, h := range individualHashes {
+						if bytes.Equal(hash[:], h) {
+							found = true
+						}
+					}
+					require.Equal(t, true, found)
+					validatorsFoundCount++
+				}
+				require.Equal(t, len(vals), validatorsFoundCount)
+
+				// check if the state validator indexes are stored properly
+				err = dbStore.db.View(func(tx *bbolt.Tx) error {
+					rcvdValhashBytes := tx.Bucket(blockRootValidatorHashesBucket).Get(blockRoot[:])
+					rcvdValHashes, sErr := snappy.Decode(nil, rcvdValhashBytes)
+					assert.NoError(t, sErr)
+					require.DeepEqual(t, hashes, rcvdValHashes)
+					return nil
+				})
+				assert.NoError(t, err)
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dbStore := setupDB(t)
+
+			// add a state with the given validators
+			vals := validators(10)
+			blockRoot := [32]byte{'A'}
+			st, _ := util.DeterministicGenesisStateCapella(t, 20)
+			err := st.SetFork(&v1alpha1.Fork{
+				PreviousVersion: params.BeaconConfig().BellatrixForkVersion,
+				CurrentVersion:  params.BeaconConfig().CapellaForkVersion,
+				Epoch:           0,
+			})
+			require.NoError(t, err)
+			assert.NoError(t, st.SetSlot(100))
+			assert.NoError(t, st.SetValidators(vals))
+			assert.NoError(t, dbStore.SaveState(context.Background(), st, blockRoot))
+
+			// enable historical state representation flag to test this
+			resetCfg := features.InitWithReset(&features.Flags{
+				EnableHistoricalSpaceRepresentation: true,
+			})
+			defer resetCfg()
+
+			tt.setup(t, dbStore, st, vals)
+			assert.NoError(t, migrateStateValidators(context.Background(), dbStore.db), "migrateArchivedIndex(tx) error")
+			tt.eval(t, dbStore, st, vals)
+		})
+	}
+}
--- a/beacon-chain/execution/engine_client.go
+++ b/beacon-chain/execution/engine_client.go
@@ -297,9 +297,6 @@ func (s *Service) ExchangeTransitionConfiguration(
 }

 func (s *Service) ExchangeCapabilities(ctx context.Context) ([]string, error) {
-	if !features.Get().EnableOptionalEngineMethods {
-		return nil, errors.New("optional engine methods not enabled")
-	}
 	ctx, span := trace.StartSpan(ctx, "powchain.engine-api-client.ExchangeCapabilities")
 	defer span.End()

@@ -491,9 +488,6 @@ func (s *Service) HeaderByNumber(ctx context.Context, number *big.Int) (*types.H

 // GetPayloadBodiesByHash returns the relevant payload bodies for the provided block hash.
 func (s *Service) GetPayloadBodiesByHash(ctx context.Context, executionBlockHashes []common.Hash) ([]*pb.ExecutionPayloadBodyV1, error) {
-	if !features.Get().EnableOptionalEngineMethods {
-		return nil, errors.New("optional engine methods not enabled")
-	}
 	ctx, span := trace.StartSpan(ctx, "powchain.engine-api-client.GetPayloadBodiesByHashV1")
 	defer span.End()

@@ -513,9 +507,6 @@ func (s *Service) GetPayloadBodiesByHash(ctx context.Context, executionBlockHash

 // GetPayloadBodiesByRange returns the relevant payload bodies for the provided range.
 func (s *Service) GetPayloadBodiesByRange(ctx context.Context, start, count uint64) ([]*pb.ExecutionPayloadBodyV1, error) {
-	if !features.Get().EnableOptionalEngineMethods {
-		return nil, errors.New("optional engine methods not enabled")
-	}
 	ctx, span := trace.StartSpan(ctx, "powchain.engine-api-client.GetPayloadBodiesByRangeV1")
 	defer span.End()

@@ -560,19 +551,7 @@ func (s *Service) ReconstructFullBlock(
 	}

 	executionBlockHash := common.BytesToHash(header.BlockHash())
-	executionBlock, err := s.ExecutionBlockByHash(ctx, executionBlockHash, true /* with txs */)
-	if err != nil {
-		return nil, fmt.Errorf("could not fetch execution block with txs by hash %#x: %v", executionBlockHash, err)
-	}
-	if executionBlock == nil {
-		return nil, fmt.Errorf("received nil execution block for request by hash %#x", executionBlockHash)
-	}
-	if bytes.Equal(executionBlock.Hash.Bytes(), []byte{}) {
-		return nil, EmptyBlockHash
-	}
-
-	executionBlock.Version = blindedBlock.Version()
-	payload, err := fullPayloadFromExecutionBlock(header, executionBlock)
+	payload, err := s.retrievePayloadFromExecutionHash(ctx, executionBlockHash, header, blindedBlock.Version())
 	if err != nil {
 		return nil, err
 	}
@@ -619,32 +598,9 @@ func (s *Service) ReconstructFullBellatrixBlockBatch(
 			executionHashes = append(executionHashes, executionBlockHash)
 		}
 	}
-	execBlocks, err := s.ExecutionBlocksByHashes(ctx, executionHashes, true /* with txs*/)
+	fullBlocks, err := s.retrievePayloadsFromExecutionHashes(ctx, executionHashes, validExecPayloads, blindedBlocks)
 	if err != nil {
-		return nil, fmt.Errorf("could not fetch execution blocks with txs by hash %#x: %v", executionHashes, err)
-	}
-
-	// For each valid payload, we reconstruct the full block from it with the
-	// blinded block.
-	fullBlocks := make([]interfaces.SignedBeaconBlock, len(blindedBlocks))
-	for sliceIdx, realIdx := range validExecPayloads {
-		b := execBlocks[sliceIdx]
-		if b == nil {
-			return nil, fmt.Errorf("received nil execution block for request by hash %#x", executionHashes[sliceIdx])
-		}
-		header, err := blindedBlocks[realIdx].Block().Body().Execution()
-		if err != nil {
-			return nil, err
-		}
-		payload, err := fullPayloadFromExecutionBlock(header, b)
-		if err != nil {
-			return nil, err
-		}
-		fullBlock, err := blocks.BuildSignedBeaconBlockFromExecutionPayload(blindedBlocks[realIdx], payload.Proto())
-		if err != nil {
-			return nil, err
-		}
-		fullBlocks[realIdx] = fullBlock
+		return nil, err
 	}
 	// For blocks that are pre-merge we simply reconstruct them via an empty
 	// execution payload.
@@ -660,6 +616,95 @@ func (s *Service) ReconstructFullBellatrixBlockBatch(
 	return fullBlocks, nil
 }

+func (s *Service) retrievePayloadFromExecutionHash(ctx context.Context, executionBlockHash common.Hash, header interfaces.ExecutionData, version int) (interfaces.ExecutionData, error) {
+	if features.Get().EnableOptionalEngineMethods {
+		pBodies, err := s.GetPayloadBodiesByHash(ctx, []common.Hash{executionBlockHash})
+		if err != nil {
+			return nil, fmt.Errorf("could not get payload body by hash %#x: %v", executionBlockHash, err)
+		}
+		if len(pBodies) != 1 {
+			return nil, errors.Errorf("could not retrieve the correct number of payload bodies: wanted 1 but got %d", len(pBodies))
+		}
+		bdy := pBodies[0]
+		return fullPayloadFromPayloadBody(header, bdy, version)
+	}
+
+	executionBlock, err := s.ExecutionBlockByHash(ctx, executionBlockHash, true /* with txs */)
+	if err != nil {
+		return nil, fmt.Errorf("could not fetch execution block with txs by hash %#x: %v", executionBlockHash, err)
+	}
+	if executionBlock == nil {
+		return nil, fmt.Errorf("received nil execution block for request by hash %#x", executionBlockHash)
+	}
+	if bytes.Equal(executionBlock.Hash.Bytes(), []byte{}) {
+		return nil, EmptyBlockHash
+	}
+
+	executionBlock.Version = version
+	return fullPayloadFromExecutionBlock(header, executionBlock)
+}
+
+func (s *Service) retrievePayloadsFromExecutionHashes(
+	ctx context.Context,
+	executionHashes []common.Hash,
+	validExecPayloads []int,
+	blindedBlocks []interfaces.ReadOnlySignedBeaconBlock) ([]interfaces.SignedBeaconBlock, error) {
+	fullBlocks := make([]interfaces.SignedBeaconBlock, len(blindedBlocks))
+	var execBlocks []*pb.ExecutionBlock
+	var payloadBodies []*pb.ExecutionPayloadBodyV1
+	var err error
+	if features.Get().EnableOptionalEngineMethods {
+		payloadBodies, err = s.GetPayloadBodiesByHash(ctx, executionHashes)
+		if err != nil {
+			return nil, fmt.Errorf("could not fetch payload bodies by hash %#x: %v", executionHashes, err)
+		}
+	} else {
+		execBlocks, err = s.ExecutionBlocksByHashes(ctx, executionHashes, true /* with txs*/)
+		if err != nil {
+			return nil, fmt.Errorf("could not fetch execution blocks with txs by hash %#x: %v", executionHashes, err)
+		}
+	}
+
+	// For each valid payload, we reconstruct the full block from it with the
+	// blinded block.
+	for sliceIdx, realIdx := range validExecPayloads {
+		var payload interfaces.ExecutionData
+		if features.Get().EnableOptionalEngineMethods {
+			b := payloadBodies[sliceIdx]
+			if b == nil {
+				return nil, fmt.Errorf("received nil payload body for request by hash %#x", executionHashes[sliceIdx])
+			}
+			header, err := blindedBlocks[realIdx].Block().Body().Execution()
+			if err != nil {
+				return nil, err
+			}
+			payload, err = fullPayloadFromPayloadBody(header, b, blindedBlocks[realIdx].Version())
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			b := execBlocks[sliceIdx]
+			if b == nil {
+				return nil, fmt.Errorf("received nil execution block for request by hash %#x", executionHashes[sliceIdx])
+			}
+			header, err := blindedBlocks[realIdx].Block().Body().Execution()
+			if err != nil {
+				return nil, err
+			}
+			payload, err = fullPayloadFromExecutionBlock(header, b)
+			if err != nil {
+				return nil, err
+			}
+		}
+		fullBlock, err := blocks.BuildSignedBeaconBlockFromExecutionPayload(blindedBlocks[realIdx], payload.Proto())
+		if err != nil {
+			return nil, err
+		}
+		fullBlocks[realIdx] = fullBlock
+	}
+	return fullBlocks, nil
+}
+
 func fullPayloadFromExecutionBlock(
 	header interfaces.ExecutionData, block *pb.ExecutionBlock,
 ) (interfaces.ExecutionData, error) {
@@ -721,6 +766,50 @@ func fullPayloadFromExecutionBlock(
 	}, 0) // We can't get the block value and don't care about the block value for this instance
 }

+func fullPayloadFromPayloadBody(
+	header interfaces.ExecutionData, body *pb.ExecutionPayloadBodyV1, bVersion int,
+) (interfaces.ExecutionData, error) {
+	if header.IsNil() || body == nil {
+		return nil, errors.New("execution block and header cannot be nil")
+	}
+
+	if bVersion == version.Bellatrix {
+		return blocks.WrappedExecutionPayload(&pb.ExecutionPayload{
+			ParentHash:    header.ParentHash(),
+			FeeRecipient:  header.FeeRecipient(),
+			StateRoot:     header.StateRoot(),
+			ReceiptsRoot:  header.ReceiptsRoot(),
+			LogsBloom:     header.LogsBloom(),
+			PrevRandao:    header.PrevRandao(),
+			BlockNumber:   header.BlockNumber(),
+			GasLimit:      header.GasLimit(),
+			GasUsed:       header.GasUsed(),
+			Timestamp:     header.Timestamp(),
+			ExtraData:     header.ExtraData(),
+			BaseFeePerGas: header.BaseFeePerGas(),
+			BlockHash:     header.BlockHash(),
+			Transactions:  body.Transactions,
+		})
+	}
+	return blocks.WrappedExecutionPayloadCapella(&pb.ExecutionPayloadCapella{
+		ParentHash:    header.ParentHash(),
+		FeeRecipient:  header.FeeRecipient(),
+		StateRoot:     header.StateRoot(),
+		ReceiptsRoot:  header.ReceiptsRoot(),
+		LogsBloom:     header.LogsBloom(),
+		PrevRandao:    header.PrevRandao(),
+		BlockNumber:   header.BlockNumber(),
+		GasLimit:      header.GasLimit(),
+		GasUsed:       header.GasUsed(),
+		Timestamp:     header.Timestamp(),
+		ExtraData:     header.ExtraData(),
+		BaseFeePerGas: header.BaseFeePerGas(),
+		BlockHash:     header.BlockHash(),
+		Transactions:  body.Transactions,
+		Withdrawals:   body.Withdrawals,
+	}, 0) // We can't get the block value and don't care about the block value for this instance
+}
+
 // Handles errors received from the RPC server according to the specification.
 func handleRPCError(err error) error {
 	if err == nil {
--- a/beacon-chain/execution/engine_client_fuzz_test.go
+++ b/beacon-chain/execution/engine_client_fuzz_test.go
@@ -115,28 +115,32 @@ func FuzzExchangeTransitionConfiguration(f *testing.F) {

 func FuzzExecutionPayload(f *testing.F) {
 	logsBloom := [256]byte{'j', 'u', 'n', 'k'}
-	execData := &engine.ExecutableData{
-		ParentHash:    common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
-		FeeRecipient:  common.Address([20]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF}),
-		StateRoot:     common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
-		ReceiptsRoot:  common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
-		LogsBloom:     logsBloom[:],
-		Random:        common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
-		Number:        math.MaxUint64,
-		GasLimit:      math.MaxUint64,
-		GasUsed:       math.MaxUint64,
-		Timestamp:     100,
-		ExtraData:     nil,
-		BaseFeePerGas: big.NewInt(math.MaxInt),
-		BlockHash:     common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
-		Transactions:  [][]byte{{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}, {0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}, {0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}, {0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}},
+	execData := &engine.ExecutionPayloadEnvelope{
+		ExecutionPayload: &engine.ExecutableData{
+			ParentHash:    common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
+			FeeRecipient:  common.Address([20]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF}),
+			StateRoot:     common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
+			ReceiptsRoot:  common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
+			LogsBloom:     logsBloom[:],
+			Random:        common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
+			Number:        math.MaxUint64,
+			GasLimit:      math.MaxUint64,
+			GasUsed:       math.MaxUint64,
+			Timestamp:     100,
+			ExtraData:     nil,
+			BaseFeePerGas: big.NewInt(math.MaxInt),
+			BlockHash:     common.Hash([32]byte{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}),
+			Transactions:  [][]byte{{0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}, {0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}, {0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}, {0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01, 0xFF, 0x01}},
+			Withdrawals:   []*types.Withdrawal{},
+		},
+		BlockValue: nil,
 	}
 	output, err := json.Marshal(execData)
 	assert.NoError(f, err)
 	f.Add(output)
 	f.Fuzz(func(t *testing.T, jsonBlob []byte) {
-		gethResp := &engine.ExecutableData{}
-		prysmResp := &pb.ExecutionPayload{}
+		gethResp := &engine.ExecutionPayloadEnvelope{}
+		prysmResp := &pb.ExecutionPayloadCapellaWithValue{}
 		gethErr := json.Unmarshal(jsonBlob, gethResp)
 		prysmErr := json.Unmarshal(jsonBlob, prysmResp)
 		assert.Equal(t, gethErr != nil, prysmErr != nil, fmt.Sprintf("geth and prysm unmarshaller return inconsistent errors. %v and %v", gethErr, prysmErr))
@@ -147,10 +151,10 @@ func FuzzExecutionPayload(f *testing.F) {
 		gethBlob, gethErr := json.Marshal(gethResp)
 		prysmBlob, prysmErr := json.Marshal(prysmResp)
 		assert.Equal(t, gethErr != nil, prysmErr != nil, "geth and prysm unmarshaller return inconsistent errors")
-		newGethResp := &engine.ExecutableData{}
+		newGethResp := &engine.ExecutionPayloadEnvelope{}
 		newGethErr := json.Unmarshal(prysmBlob, newGethResp)
 		assert.NoError(t, newGethErr)
-		newGethResp2 := &engine.ExecutableData{}
+		newGethResp2 := &engine.ExecutionPayloadEnvelope{}
 		newGethErr = json.Unmarshal(gethBlob, newGethResp2)
 		assert.NoError(t, newGethErr)

--- a/beacon-chain/execution/log_processing.go
+++ b/beacon-chain/execution/log_processing.go
@@ -69,12 +69,12 @@ func (s *Service) ProcessETH1Block(ctx context.Context, blkNum *big.Int) error {
 	if err != nil {
 		return err
 	}
-	for _, filterLog := range logs {
+	for i, filterLog := range logs {
 		// ignore logs that are not of the required block number
 		if filterLog.BlockNumber != blkNum.Uint64() {
 			continue
 		}
-		if err := s.ProcessLog(ctx, filterLog); err != nil {
+		if err := s.ProcessLog(ctx, &logs[i]); err != nil {
 			return errors.Wrap(err, "could not process log")
 		}
 	}
@@ -88,7 +88,7 @@ func (s *Service) ProcessETH1Block(ctx context.Context, blkNum *big.Int) error {

 // ProcessLog is the main method which handles the processing of all
 // logs from the deposit contract on the eth1 chain.
-func (s *Service) ProcessLog(ctx context.Context, depositLog gethtypes.Log) error {
+func (s *Service) ProcessLog(ctx context.Context, depositLog *gethtypes.Log) error {
 	s.processingLock.RLock()
 	defer s.processingLock.RUnlock()
 	// Process logs according to their event signature.
@@ -108,7 +108,7 @@ func (s *Service) ProcessLog(ctx context.Context, depositLog gethtypes.Log) erro
 // ProcessDepositLog processes the log which had been received from
 // the eth1 chain by trying to ascertain which participant deposited
 // in the contract.
-func (s *Service) ProcessDepositLog(ctx context.Context, depositLog gethtypes.Log) error {
+func (s *Service) ProcessDepositLog(ctx context.Context, depositLog *gethtypes.Log) error {
 	pubkey, withdrawalCredentials, amount, signature, merkleTreeIndex, err := contracts.UnpackDepositLogData(depositLog.Data)
 	if err != nil {
 		return errors.Wrap(err, "Could not unpack log")
@@ -406,7 +406,7 @@ func (s *Service) processBlockInBatch(ctx context.Context, currentBlockNum uint6
 	lastReqBlock := s.latestEth1Data.LastRequestedBlock
 	s.latestEth1DataLock.RUnlock()

-	for _, filterLog := range logs {
+	for i, filterLog := range logs {
 		if filterLog.BlockNumber > currentBlockNum {
 			if err := s.checkHeaderRange(ctx, currentBlockNum, filterLog.BlockNumber-1, headersMap, requestHeaders); err != nil {
 				return 0, 0, err
@@ -417,7 +417,7 @@ func (s *Service) processBlockInBatch(ctx context.Context, currentBlockNum uint6
 			s.latestEth1DataLock.Unlock()
 			currentBlockNum = filterLog.BlockNumber
 		}
-		if err := s.ProcessLog(ctx, filterLog); err != nil {
+		if err := s.ProcessLog(ctx, &logs[i]); err != nil {
 			// In the event the execution client gives us a garbled/bad log
 			// we reset the last requested block to the previous valid block range. This
 			// prevents the beacon from advancing processing of logs to another range
--- a/beacon-chain/execution/log_processing_test.go
+++ b/beacon-chain/execution/log_processing_test.go
@@ -79,7 +79,7 @@ func TestProcessDepositLog_OK(t *testing.T) {
 		t.Fatal("no logs")
 	}

-	err = web3Service.ProcessLog(context.Background(), logs[0])
+	err = web3Service.ProcessLog(context.Background(), &logs[0])
 	require.NoError(t, err)

 	require.LogsDoNotContain(t, hook, "Could not unpack log")
@@ -149,9 +149,9 @@ func TestProcessDepositLog_InsertsPendingDeposit(t *testing.T) {

 	web3Service.chainStartData.Chainstarted = true

-	err = web3Service.ProcessDepositLog(context.Background(), logs[0])
+	err = web3Service.ProcessDepositLog(context.Background(), &logs[0])
 	require.NoError(t, err)
-	err = web3Service.ProcessDepositLog(context.Background(), logs[1])
+	err = web3Service.ProcessDepositLog(context.Background(), &logs[1])
 	require.NoError(t, err)

 	pendingDeposits := web3Service.cfg.depositCache.PendingDeposits(context.Background(), nil /*blockNum*/)
@@ -272,8 +272,8 @@ func TestProcessETH2GenesisLog_8DuplicatePubkeys(t *testing.T) {
 	logs, err := testAcc.Backend.FilterLogs(web3Service.ctx, query)
 	require.NoError(t, err, "Unable to retrieve logs")

-	for _, log := range logs {
-		err = web3Service.ProcessLog(context.Background(), log)
+	for i := range logs {
+		err = web3Service.ProcessLog(context.Background(), &logs[i])
 		require.NoError(t, err)
 	}
 	assert.Equal(t, false, web3Service.chainStartData.Chainstarted, "Genesis has been triggered despite being 8 duplicate keys")
@@ -351,8 +351,8 @@ func TestProcessETH2GenesisLog(t *testing.T) {
 	stateSub := web3Service.cfg.stateNotifier.StateFeed().Subscribe(stateChannel)
 	defer stateSub.Unsubscribe()

-	for _, log := range logs {
-		err = web3Service.ProcessLog(context.Background(), log)
+	for i := range logs {
+		err = web3Service.ProcessLog(context.Background(), &logs[i])
 		require.NoError(t, err)
 	}

--- a/beacon-chain/forkchoice/doubly-linked-tree/forkchoice.go
+++ b/beacon-chain/forkchoice/doubly-linked-tree/forkchoice.go
@@ -265,6 +265,7 @@ func (f *ForkChoice) IsViableForCheckpoint(cp *forkchoicetypes.Checkpoint) (bool
 // validators' latest votes.
 func (f *ForkChoice) updateBalances() error {
 	newBalances := f.justifiedBalances
+	zHash := params.BeaconConfig().ZeroHash

 	for index, vote := range f.votes {
 		// Skip if validator has been slashed
@@ -273,7 +274,7 @@ func (f *ForkChoice) updateBalances() error {
 		}
 		// Skip if validator has never voted for current root and next root (i.e. if the
 		// votes are zero hash aka genesis block), there's nothing to compute.
-		if vote.currentRoot == params.BeaconConfig().ZeroHash && vote.nextRoot == params.BeaconConfig().ZeroHash {
+		if vote.currentRoot == zHash && vote.nextRoot == zHash {
 			continue
 		}

@@ -293,7 +294,7 @@ func (f *ForkChoice) updateBalances() error {
 			// Ignore the vote if the root is not in fork choice
 			// store, that means we have not seen the block before.
 			nextNode, ok := f.store.nodeByRoot[vote.nextRoot]
-			if ok && vote.nextRoot != params.BeaconConfig().ZeroHash {
+			if ok && vote.nextRoot != zHash {
 				// Protection against nil node
 				if nextNode == nil {
 					return errors.Wrap(ErrNilNode, "could not update balances")
@@ -302,7 +303,7 @@ func (f *ForkChoice) updateBalances() error {
 			}

 			currentNode, ok := f.store.nodeByRoot[vote.currentRoot]
-			if ok && vote.currentRoot != params.BeaconConfig().ZeroHash {
+			if ok && vote.currentRoot != zHash {
 				// Protection against nil node
 				if currentNode == nil {
 					return errors.Wrap(ErrNilNode, "could not update balances")
--- a/beacon-chain/forkchoice/doubly-linked-tree/on_tick.go
+++ b/beacon-chain/forkchoice/doubly-linked-tree/on_tick.go
@@ -31,9 +31,7 @@ import (
 //	        store.justified_checkpoint = store.best_justified_checkpoint
 func (f *ForkChoice) NewSlot(ctx context.Context, slot primitives.Slot) error {
 	// Reset proposer boost root
-	if err := f.resetBoostedProposerRoot(ctx); err != nil {
-		return errors.Wrap(err, "could not reset boosted proposer root in fork choice")
-	}
+	f.store.proposerBoostRoot = [32]byte{}

 	// Return if it's not a new epoch.
 	if !slots.IsEpochStart(slot) {
--- a/beacon-chain/forkchoice/doubly-linked-tree/optimistic_sync.go
+++ b/beacon-chain/forkchoice/doubly-linked-tree/optimistic_sync.go
@@ -7,7 +7,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 )

-func (s *Store) setOptimisticToInvalid(ctx context.Context, root, parentRoot, payloadHash [32]byte) ([][32]byte, error) {
+func (s *Store) setOptimisticToInvalid(ctx context.Context, root, parentRoot, lastValidHash [32]byte) ([][32]byte, error) {
 	invalidRoots := make([][32]byte, 0)
 	node, ok := s.nodeByRoot[root]
 	if !ok {
@@ -16,7 +16,7 @@ func (s *Store) setOptimisticToInvalid(ctx context.Context, root, parentRoot, pa
 			return invalidRoots, errors.Wrap(ErrNilNode, "could not set node to invalid")
 		}
 		// return early if the parent is LVH
-		if node.payloadHash == payloadHash {
+		if node.payloadHash == lastValidHash {
 			return invalidRoots, nil
 		}
 	} else {
@@ -28,7 +28,7 @@ func (s *Store) setOptimisticToInvalid(ctx context.Context, root, parentRoot, pa
 		}
 	}
 	firstInvalid := node
-	for ; firstInvalid.parent != nil && firstInvalid.parent.payloadHash != payloadHash; firstInvalid = firstInvalid.parent {
+	for ; firstInvalid.parent != nil && firstInvalid.parent.payloadHash != lastValidHash; firstInvalid = firstInvalid.parent {
 		if ctx.Err() != nil {
 			return invalidRoots, ctx.Err()
 		}
--- a/beacon-chain/forkchoice/doubly-linked-tree/proposer_boost.go
+++ b/beacon-chain/forkchoice/doubly-linked-tree/proposer_boost.go
@@ -1,19 +1,12 @@
 package doublylinkedtree

 import (
-	"context"
 	"fmt"

 	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v4/config/params"
 )

-// resetBoostedProposerRoot sets the value of the proposer boosted root to zeros.
-func (f *ForkChoice) resetBoostedProposerRoot(_ context.Context) error {
-	f.store.proposerBoostRoot = [32]byte{}
-	return nil
-}
-
 // applyProposerBoostScore applies the current proposer boost scores to the
 // relevant nodes.
 func (f *ForkChoice) applyProposerBoostScore() error {
--- a/beacon-chain/forkchoice/doubly-linked-tree/reorg_late_blocks.go
+++ b/beacon-chain/forkchoice/doubly-linked-tree/reorg_late_blocks.go
@@ -82,6 +82,11 @@ func (f *ForkChoice) ShouldOverrideFCU() (override bool) {
 	if head.weight*100 > f.store.committeeWeight*params.BeaconConfig().ReorgWeightThreshold {
 		return
 	}
+
+	// Only orphan a block if the parent LMD vote is strong
+	if parent.weight*100 < f.store.committeeWeight*params.BeaconConfig().ReorgParentWeightThreshold {
+		return
+	}
 	return true
 }

@@ -137,6 +142,11 @@ func (f *ForkChoice) GetProposerHead() [32]byte {
 		return head.root
 	}

+	// Only orphan a block if the parent LMD vote is strong
+	if parent.weight*100 < f.store.committeeWeight*params.BeaconConfig().ReorgParentWeightThreshold {
+		return head.root
+	}
+
 	// Only reorg if we are proposing early
 	secs, err := slots.SecondsSinceSlotStart(head.slot+1, f.store.genesisTime, uint64(time.Now().Unix()))
 	if err != nil {
--- a/beacon-chain/forkchoice/doubly-linked-tree/reorg_late_blocks_test.go
+++ b/beacon-chain/forkchoice/doubly-linked-tree/reorg_late_blocks_test.go
@@ -22,7 +22,11 @@ func TestForkChoice_ShouldOverrideFCU(t *testing.T) {
 	st, root, err := prepareForkchoiceState(ctx, 1, [32]byte{'a'}, [32]byte{}, [32]byte{'A'}, 0, 0)
 	require.NoError(t, err)
 	require.NoError(t, f.InsertNode(ctx, st, root))
-	f.ProcessAttestation(ctx, []uint64{0, 1, 2}, root, 0)
+	attesters := make([]uint64, f.numActiveValidators-64)
+	for i := range attesters {
+		attesters[i] = uint64(i + 64)
+	}
+	f.ProcessAttestation(ctx, attesters, root, 0)

 	driftGenesisTime(f, 2, orphanLateBlockFirstThreshold+1)
 	st, root, err = prepareForkchoiceState(ctx, 2, [32]byte{'b'}, [32]byte{'a'}, [32]byte{'B'}, 0, 0)
@@ -80,6 +84,12 @@ func TestForkChoice_ShouldOverrideFCU(t *testing.T) {
 		require.Equal(t, false, f.ShouldOverrideFCU())
 		f.store.headNode.parent = saved
 	})
+	t.Run("parent is weak", func(t *testing.T) {
+		saved := f.store.headNode.parent.weight
+		f.store.headNode.parent.weight = 0
+		require.Equal(t, false, f.ShouldOverrideFCU())
+		f.store.headNode.parent.weight = saved
+	})
 	t.Run("Head is strong", func(t *testing.T) {
 		f.store.headNode.weight = f.store.committeeWeight
 		require.Equal(t, false, f.ShouldOverrideFCU())
@@ -101,7 +111,11 @@ func TestForkChoice_GetProposerHead(t *testing.T) {
 	st, root, err := prepareForkchoiceState(ctx, 1, parentRoot, [32]byte{}, [32]byte{'A'}, 0, 0)
 	require.NoError(t, err)
 	require.NoError(t, f.InsertNode(ctx, st, root))
-	f.ProcessAttestation(ctx, []uint64{0, 1, 2}, root, 0)
+	attesters := make([]uint64, f.numActiveValidators-64)
+	for i := range attesters {
+		attesters[i] = uint64(i + 64)
+	}
+	f.ProcessAttestation(ctx, attesters, root, 0)

 	driftGenesisTime(f, 3, 1)
 	childRoot := [32]byte{'b'}
@@ -161,6 +175,12 @@ func TestForkChoice_GetProposerHead(t *testing.T) {
 		require.Equal(t, childRoot, f.GetProposerHead())
 		f.store.headNode.parent = saved
 	})
+	t.Run("parent is weak", func(t *testing.T) {
+		saved := f.store.headNode.parent.weight
+		f.store.headNode.parent.weight = 0
+		require.Equal(t, false, f.ShouldOverrideFCU())
+		f.store.headNode.parent.weight = saved
+	})
 	t.Run("Head is strong", func(t *testing.T) {
 		f.store.headNode.weight = f.store.committeeWeight
 		require.Equal(t, childRoot, f.GetProposerHead())
--- a/beacon-chain/monitor/process_sync_committee.go
+++ b/beacon-chain/monitor/process_sync_committee.go
@@ -6,6 +6,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/runtime/version"
 	"github.com/sirupsen/logrus"
 )

@@ -29,6 +30,9 @@ func (s *Service) processSyncAggregate(state state.BeaconState, blk interfaces.R
 	if blk == nil || blk.Body() == nil {
 		return
 	}
+	if blk.Version() == version.Phase0 {
+		return
+	}
 	bits, err := blk.Body().SyncAggregate()
 	if err != nil {
 		log.WithError(err).Error("Could not get SyncAggregate")
--- a/beacon-chain/monitor/service.go
+++ b/beacon-chain/monitor/service.go
@@ -114,19 +114,11 @@ func (s *Service) Start() {
 		"ValidatorIndices": tracked,
 	}).Info("Starting service")

-	stateChannel := make(chan *feed.Event, 1)
-	stateSub := s.config.StateNotifier.StateFeed().Subscribe(stateChannel)
-
-	go s.run(stateChannel, stateSub)
+	go s.run()
 }

 // run waits until the beacon is synced and starts the monitoring system.
-func (s *Service) run(stateChannel chan *feed.Event, stateSub event.Subscription) {
-	if stateChannel == nil {
-		log.Error("State state is nil")
-		return
-	}
-
+func (s *Service) run() {
 	if err := s.waitForSync(s.config.InitialSyncComplete); err != nil {
 		log.WithError(err)
 		return
@@ -154,6 +146,8 @@ func (s *Service) run(stateChannel chan *feed.Event, stateSub event.Subscription
 	s.isLogging = true
 	s.Unlock()

+	stateChannel := make(chan *feed.Event, 1)
+	stateSub := s.config.StateNotifier.StateFeed().Subscribe(stateChannel)
 	s.monitorRoutine(stateChannel, stateSub)
 }

--- a/beacon-chain/monitor/service_test.go
+++ b/beacon-chain/monitor/service_test.go
@@ -271,11 +271,9 @@ func TestWaitForSyncCanceled(t *testing.T) {
 func TestRun(t *testing.T) {
 	hook := logTest.NewGlobal()
 	s := setupService(t)
-	stateChannel := make(chan *feed.Event, 1)
-	stateSub := s.config.StateNotifier.StateFeed().Subscribe(stateChannel)

 	go func() {
-		s.run(stateChannel, stateSub)
+		s.run()
 	}()
 	close(s.config.InitialSyncComplete)

--- a/beacon-chain/node/config_test.go
+++ b/beacon-chain/node/config_test.go
@@ -158,8 +158,7 @@ func TestConfigureNetwork_ConfigFile(t *testing.T) {
 			return cmd.LoadFlagsFromConfig(cliCtx, comFlags)
 		},
 		Action: func(cliCtx *cli.Context) error {
-			//TODO: https://github.com/urfave/cli/issues/1197 right now does not set flag
-			require.Equal(t, false, cliCtx.IsSet(cmd.BootstrapNode.Name))
+			require.Equal(t, true, cliCtx.IsSet(cmd.BootstrapNode.Name))

 			require.Equal(t, strings.Join([]string{"node1", "node2"}, ","),
 				strings.Join(cliCtx.StringSlice(cmd.BootstrapNode.Name), ","))
--- a/beacon-chain/node/node.go
+++ b/beacon-chain/node/node.go
@@ -212,6 +212,11 @@ func New(cliCtx *cli.Context, opts ...Option) (*BeaconNode, error) {

 	log.Debugln("Starting State Gen")
 	if err := beacon.startStateGen(ctx, bfs, beacon.forkChoicer); err != nil {
+		if errors.Is(err, stategen.ErrNoGenesisBlock) {
+			log.Errorf("No genesis block/state is found. Prysm only provides a mainnet genesis "+
+				"state bundled in the application. You must provide the --%s or --%s flag to load "+
+				"a genesis block/state for this network.", "genesis-state", "genesis-beacon-api-url")
+		}
 		return nil, err
 	}

@@ -230,13 +235,13 @@ func New(cliCtx *cli.Context, opts ...Option) (*BeaconNode, error) {
 		return nil, err
 	}

-	log.Debugln("Registering Determinstic Genesis Service")
-	if err := beacon.registerDeterminsticGenesisService(); err != nil {
+	log.Debugln("Registering Deterministic Genesis Service")
+	if err := beacon.registerDeterministicGenesisService(); err != nil {
 		return nil, err
 	}

 	log.Debugln("Registering Blockchain Service")
-	if err := beacon.registerBlockchainService(beacon.forkChoicer, synchronizer); err != nil {
+	if err := beacon.registerBlockchainService(beacon.forkChoicer, synchronizer, beacon.initialSyncComplete); err != nil {
 		return nil, err
 	}

@@ -581,7 +586,8 @@ func (b *BeaconNode) fetchBuilderService() *builder.Service {

 func (b *BeaconNode) registerAttestationPool() error {
 	s, err := attestations.NewService(b.ctx, &attestations.Config{
-		Pool: b.attestationPool,
+		Pool:                b.attestationPool,
+		InitialSyncComplete: b.initialSyncComplete,
 	})
 	if err != nil {
 		return errors.Wrap(err, "could not register atts pool service")
@@ -589,7 +595,7 @@ func (b *BeaconNode) registerAttestationPool() error {
 	return b.services.RegisterService(s)
 }

-func (b *BeaconNode) registerBlockchainService(fc forkchoice.ForkChoicer, gs *startup.ClockSynchronizer) error {
+func (b *BeaconNode) registerBlockchainService(fc forkchoice.ForkChoicer, gs *startup.ClockSynchronizer, syncComplete chan struct{}) error {
 	var web3Service *execution.Service
 	if err := b.services.FetchService(&web3Service); err != nil {
 		return err
@@ -620,6 +626,7 @@ func (b *BeaconNode) registerBlockchainService(fc forkchoice.ForkChoicer, gs *st
 		blockchain.WithFinalizedStateAtStartUp(b.finalizedStateAtStartUp),
 		blockchain.WithProposerIdsCache(b.proposerIdsCache),
 		blockchain.WithClockSynchronizer(gs),
+		blockchain.WithSyncComplete(syncComplete),
 	)

 	blockchainService, err := blockchain.NewService(b.ctx, opts...)
@@ -922,7 +929,7 @@ func (b *BeaconNode) registerGRPCGateway(router *mux.Router) error {
 	return b.services.RegisterService(g)
 }

-func (b *BeaconNode) registerDeterminsticGenesisService() error {
+func (b *BeaconNode) registerDeterministicGenesisService() error {
 	genesisTime := b.cliCtx.Uint64(flags.InteropGenesisTimeFlag.Name)
 	genesisValidators := b.cliCtx.Uint64(flags.InteropNumValidatorsFlag.Name)

@@ -985,7 +992,8 @@ func (b *BeaconNode) registerBuilderService(cliCtx *cli.Context) error {
 	opts := append(b.serviceFlagOpts.builderOpts,
 		builder.WithHeadFetcher(chainService),
 		builder.WithDatabase(b.db))
-	if cliCtx.Bool(flags.EnableRegistrationCache.Name) {
+	// make cache the default.
+	if !cliCtx.Bool(features.DisableRegistrationCache.Name) {
 		opts = append(opts, builder.WithRegistrationCache())
 	}
 	svc, err := builder.NewService(b.ctx, opts...)
--- a/beacon-chain/operations/attestations/BUILD.bazel
+++ b/beacon-chain/operations/attestations/BUILD.bazel
@@ -18,6 +18,7 @@ go_library(
    deps = [
        "//beacon-chain/operations/attestations/kv:go_default_library",
        "//cache/lru:go_default_library",
+        "//config/features:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//crypto/hash:go_default_library",
@@ -46,6 +47,7 @@ go_test(
    deps = [
        "//async:go_default_library",
        "//beacon-chain/operations/attestations/kv:go_default_library",
+        "//config/features:go_default_library",
        "//config/fieldparams:go_default_library",
        "//config/params:go_default_library",
        "//crypto/bls:go_default_library",
--- a/beacon-chain/operations/attestations/kv/BUILD.bazel
+++ b/beacon-chain/operations/attestations/kv/BUILD.bazel
@@ -14,6 +14,7 @@ go_library(
    visibility = ["//beacon-chain:__subpackages__"],
    deps = [
        "//beacon-chain/core/helpers:go_default_library",
+        "//config/features:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//crypto/hash:go_default_library",
@@ -39,8 +40,8 @@ go_test(
    ],
    embed = [":go_default_library"],
    deps = [
+        "//config/features:go_default_library",
        "//config/fieldparams:go_default_library",
-        "//consensus-types/primitives:go_default_library",
        "//crypto/bls:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
        "//testing/assert:go_default_library",
--- a/beacon-chain/operations/attestations/kv/aggregated.go
+++ b/beacon-chain/operations/attestations/kv/aggregated.go
@@ -2,9 +2,12 @@ package kv

 import (
 	"context"
+	"runtime"
+	"sync"

 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
 	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	attaggregation "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1/attestation/aggregation/attestations"
@@ -23,21 +26,11 @@ func (c *AttCaches) AggregateUnaggregatedAttestations(ctx context.Context) error
 	if err != nil {
 		return err
 	}
-	return c.aggregateUnaggregatedAttestations(ctx, unaggregatedAtts)
+	return c.aggregateUnaggregatedAtts(ctx, unaggregatedAtts)
 }

-// AggregateUnaggregatedAttestationsBySlotIndex aggregates the unaggregated attestations and saves
-// newly aggregated attestations in the pool. Unaggregated attestations are filtered by slot and
-// committee index.
-func (c *AttCaches) AggregateUnaggregatedAttestationsBySlotIndex(ctx context.Context, slot primitives.Slot, committeeIndex primitives.CommitteeIndex) error {
-	ctx, span := trace.StartSpan(ctx, "operations.attestations.kv.AggregateUnaggregatedAttestationsBySlotIndex")
-	defer span.End()
-	unaggregatedAtts := c.UnaggregatedAttestationsBySlotIndex(ctx, slot, committeeIndex)
-	return c.aggregateUnaggregatedAttestations(ctx, unaggregatedAtts)
-}
-
-func (c *AttCaches) aggregateUnaggregatedAttestations(ctx context.Context, unaggregatedAtts []*ethpb.Attestation) error {
-	ctx, span := trace.StartSpan(ctx, "operations.attestations.kv.aggregateUnaggregatedAttestations")
+func (c *AttCaches) aggregateUnaggregatedAtts(ctx context.Context, unaggregatedAtts []*ethpb.Attestation) error {
+	_, span := trace.StartSpan(ctx, "operations.attestations.kv.aggregateUnaggregatedAtts")
 	defer span.End()

 	attsByDataRoot := make(map[[32]byte][]*ethpb.Attestation, len(unaggregatedAtts))
@@ -52,26 +45,30 @@ func (c *AttCaches) aggregateUnaggregatedAttestations(ctx context.Context, unagg
 	// Aggregate unaggregated attestations from the pool and save them in the pool.
 	// Track the unaggregated attestations that aren't able to aggregate.
 	leftOverUnaggregatedAtt := make(map[[32]byte]bool)
-	for _, atts := range attsByDataRoot {
-		aggregatedAtts := make([]*ethpb.Attestation, 0, len(atts))
-		processedAtts, err := attaggregation.Aggregate(atts)
-		if err != nil {
-			return err
-		}
-		for _, att := range processedAtts {
-			if helpers.IsAggregated(att) {
-				aggregatedAtts = append(aggregatedAtts, att)
+
+	if features.Get().AggregateParallel {
+		leftOverUnaggregatedAtt = c.aggregateParallel(attsByDataRoot, leftOverUnaggregatedAtt)
+	} else {
+		for _, atts := range attsByDataRoot {
+			aggregated, err := attaggregation.AggregateDisjointOneBitAtts(atts)
+			if err != nil {
+				return errors.Wrap(err, "could not aggregate unaggregated attestations")
+			}
+			if aggregated == nil {
+				return errors.New("could not aggregate unaggregated attestations")
+			}
+			if helpers.IsAggregated(aggregated) {
+				if err := c.SaveAggregatedAttestations([]*ethpb.Attestation{aggregated}); err != nil {
+					return err
+				}
 			} else {
-				h, err := hashFn(att)
+				h, err := hashFn(aggregated)
 				if err != nil {
 					return err
 				}
 				leftOverUnaggregatedAtt[h] = true
 			}
 		}
-		if err := c.SaveAggregatedAttestations(aggregatedAtts); err != nil {
-			return err
-		}
 	}

 	// Remove the unaggregated attestations from the pool that were successfully aggregated.
@@ -87,10 +84,61 @@ func (c *AttCaches) aggregateUnaggregatedAttestations(ctx context.Context, unagg
 			return err
 		}
 	}
-
 	return nil
 }

+// aggregateParallel aggregates attestations in parallel for `atts` and saves them in the pool,
+// returns the unaggregated attestations that weren't able to aggregate.
+// Given `n` CPU cores, it creates a channel of size `n` and spawns `n` goroutines to aggregate attestations
+func (c *AttCaches) aggregateParallel(atts map[[32]byte][]*ethpb.Attestation, leftOver map[[32]byte]bool) map[[32]byte]bool {
+	var leftoverLock sync.Mutex
+	wg := sync.WaitGroup{}
+
+	n := runtime.GOMAXPROCS(0) // defaults to the value of runtime.NumCPU
+	ch := make(chan []*ethpb.Attestation, n)
+	wg.Add(n)
+	for i := 0; i < n; i++ {
+		go func() {
+			defer wg.Done()
+			for as := range ch {
+				aggregated, err := attaggregation.AggregateDisjointOneBitAtts(as)
+				if err != nil {
+					log.WithError(err).Error("could not aggregate unaggregated attestations")
+					continue
+				}
+				if aggregated == nil {
+					log.Error("nil aggregated attestation")
+					continue
+				}
+				if helpers.IsAggregated(aggregated) {
+					if err := c.SaveAggregatedAttestations([]*ethpb.Attestation{aggregated}); err != nil {
+						log.WithError(err).Error("could not save aggregated attestation")
+						continue
+					}
+				} else {
+					h, err := hashFn(aggregated)
+					if err != nil {
+						log.WithError(err).Error("could not hash attestation")
+						continue
+					}
+					leftoverLock.Lock()
+					leftOver[h] = true
+					leftoverLock.Unlock()
+				}
+			}
+		}()
+	}
+
+	for _, as := range atts {
+		ch <- as
+	}
+
+	close(ch)
+	wg.Wait()
+
+	return leftOver
+}
+
 // SaveAggregatedAttestation saves an aggregated attestation in cache.
 func (c *AttCaches) SaveAggregatedAttestation(att *ethpb.Attestation) error {
 	if err := helpers.ValidateNilAttestation(att); err != nil {
@@ -168,7 +216,7 @@ func (c *AttCaches) AggregatedAttestations() []*ethpb.Attestation {
 // AggregatedAttestationsBySlotIndex returns the aggregated attestations in cache,
 // filtered by committee index and slot.
 func (c *AttCaches) AggregatedAttestationsBySlotIndex(ctx context.Context, slot primitives.Slot, committeeIndex primitives.CommitteeIndex) []*ethpb.Attestation {
-	ctx, span := trace.StartSpan(ctx, "operations.attestations.kv.AggregatedAttestationsBySlotIndex")
+	_, span := trace.StartSpan(ctx, "operations.attestations.kv.AggregatedAttestationsBySlotIndex")
 	defer span.End()

 	atts := make([]*ethpb.Attestation, 0)
--- a/beacon-chain/operations/attestations/kv/aggregated_test.go
+++ b/beacon-chain/operations/attestations/kv/aggregated_test.go
@@ -9,7 +9,7 @@ import (
 	"github.com/pkg/errors"
 	fssz "github.com/prysmaticlabs/fastssz"
 	"github.com/prysmaticlabs/go-bitfield"
-	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
 	"github.com/prysmaticlabs/prysm/v4/crypto/bls"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v4/testing/assert"
@@ -18,6 +18,11 @@ import (
 )

 func TestKV_Aggregated_AggregateUnaggregatedAttestations(t *testing.T) {
+	resetFn := features.InitWithReset(&features.Flags{
+		AggregateParallel: true,
+	})
+	defer resetFn()
+
 	cache := NewAttCaches()
 	priv, err := bls.RandKey()
 	require.NoError(t, err)
@@ -39,61 +44,6 @@ func TestKV_Aggregated_AggregateUnaggregatedAttestations(t *testing.T) {
 	require.Equal(t, 1, len(cache.AggregatedAttestationsBySlotIndex(context.Background(), 2, 0)), "Did not aggregate correctly")
 }

-func TestKV_Aggregated_AggregateUnaggregatedAttestationsBySlotIndex(t *testing.T) {
-	cache := NewAttCaches()
-	genData := func(slot primitives.Slot, committeeIndex primitives.CommitteeIndex) *ethpb.AttestationData {
-		return util.HydrateAttestationData(&ethpb.AttestationData{
-			Slot:           slot,
-			CommitteeIndex: committeeIndex,
-		})
-	}
-	genSign := func() []byte {
-		priv, err := bls.RandKey()
-		require.NoError(t, err)
-		return priv.Sign([]byte{'a'}).Marshal()
-	}
-
-	atts := []*ethpb.Attestation{
-		// The first slot.
-		{AggregationBits: bitfield.Bitlist{0b1001}, Data: genData(1, 2), Signature: genSign()},
-		{AggregationBits: bitfield.Bitlist{0b1010}, Data: genData(1, 2), Signature: genSign()},
-		{AggregationBits: bitfield.Bitlist{0b1100}, Data: genData(1, 2), Signature: genSign()},
-		{AggregationBits: bitfield.Bitlist{0b1001}, Data: genData(1, 3), Signature: genSign()},
-		{AggregationBits: bitfield.Bitlist{0b1100}, Data: genData(1, 3), Signature: genSign()},
-		// The second slot.
-		{AggregationBits: bitfield.Bitlist{0b1001}, Data: genData(2, 3), Signature: genSign()},
-		{AggregationBits: bitfield.Bitlist{0b1010}, Data: genData(2, 3), Signature: genSign()},
-		{AggregationBits: bitfield.Bitlist{0b1100}, Data: genData(2, 4), Signature: genSign()},
-	}
-	ctx := context.Background()
-
-	// Make sure that no error is produced if aggregation is requested on empty unaggregated list.
-	require.NoError(t, cache.AggregateUnaggregatedAttestationsBySlotIndex(ctx, 1, 2))
-	require.NoError(t, cache.AggregateUnaggregatedAttestationsBySlotIndex(ctx, 2, 3))
-	require.Equal(t, 0, len(cache.UnaggregatedAttestationsBySlotIndex(ctx, 1, 2)))
-	require.Equal(t, 0, len(cache.AggregatedAttestationsBySlotIndex(ctx, 1, 2)), "Did not aggregate correctly")
-	require.Equal(t, 0, len(cache.UnaggregatedAttestationsBySlotIndex(ctx, 1, 3)))
-	require.Equal(t, 0, len(cache.AggregatedAttestationsBySlotIndex(ctx, 1, 3)), "Did not aggregate correctly")
-
-	// Persist unaggregated attestations, and aggregate on per slot/committee index base.
-	require.NoError(t, cache.SaveUnaggregatedAttestations(atts))
-	require.NoError(t, cache.AggregateUnaggregatedAttestationsBySlotIndex(ctx, 1, 2))
-	require.NoError(t, cache.AggregateUnaggregatedAttestationsBySlotIndex(ctx, 2, 3))
-
-	// Committee attestations at a slot should be aggregated.
-	require.Equal(t, 0, len(cache.UnaggregatedAttestationsBySlotIndex(ctx, 1, 2)))
-	require.Equal(t, 1, len(cache.AggregatedAttestationsBySlotIndex(ctx, 1, 2)), "Did not aggregate correctly")
-	// Committee attestations haven't been aggregated.
-	require.Equal(t, 2, len(cache.UnaggregatedAttestationsBySlotIndex(ctx, 1, 3)))
-	require.Equal(t, 0, len(cache.AggregatedAttestationsBySlotIndex(ctx, 1, 3)), "Did not aggregate correctly")
-	// Committee at a second slot is aggregated.
-	require.Equal(t, 0, len(cache.UnaggregatedAttestationsBySlotIndex(ctx, 2, 3)))
-	require.Equal(t, 1, len(cache.AggregatedAttestationsBySlotIndex(ctx, 2, 3)), "Did not aggregate correctly")
-	// The second committee at second slot is not aggregated.
-	require.Equal(t, 1, len(cache.UnaggregatedAttestationsBySlotIndex(ctx, 2, 4)))
-	require.Equal(t, 0, len(cache.AggregatedAttestationsBySlotIndex(ctx, 2, 4)), "Did not aggregate correctly")
-}
-
 func TestKV_Aggregated_SaveAggregatedAttestation(t *testing.T) {
 	tests := []struct {
 		name          string
--- a/beacon-chain/operations/attestations/metrics.go
+++ b/beacon-chain/operations/attestations/metrics.go
@@ -30,6 +30,20 @@ var (
 		Name: "expired_block_atts_total",
 		Help: "The number of expired and deleted block attestations in the pool.",
 	})
+	batchForkChoiceAttsT1 = promauto.NewHistogram(
+		prometheus.HistogramOpts{
+			Name:    "aggregate_attestations_t1",
+			Help:    "Captures times of attestation aggregation in milliseconds during the first interval per slot",
+			Buckets: []float64{100, 200, 500, 1000, 1500, 2000, 2500, 3500},
+		},
+	)
+	batchForkChoiceAttsT2 = promauto.NewHistogram(
+		prometheus.HistogramOpts{
+			Name:    "aggregate_attestations_t2",
+			Help:    "Captures times of attestation aggregation in milliseconds during the second interval per slot",
+			Buckets: []float64{10, 40, 100, 200, 600},
+		},
+	)
 )

 func (s *Service) updateMetrics() {
--- a/beacon-chain/operations/attestations/pool.go
+++ b/beacon-chain/operations/attestations/pool.go
@@ -15,7 +15,6 @@ import (
 type Pool interface {
 	// For Aggregated attestations
 	AggregateUnaggregatedAttestations(ctx context.Context) error
-	AggregateUnaggregatedAttestationsBySlotIndex(ctx context.Context, slot primitives.Slot, committeeIndex primitives.CommitteeIndex) error
 	SaveAggregatedAttestation(att *ethpb.Attestation) error
 	SaveAggregatedAttestations(atts []*ethpb.Attestation) error
 	AggregatedAttestations() []*ethpb.Attestation
--- a/beacon-chain/operations/attestations/prepare_forkchoice.go
+++ b/beacon-chain/operations/attestations/prepare_forkchoice.go
@@ -7,6 +7,8 @@ import (
 	"time"

 	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
+	"github.com/prysmaticlabs/prysm/v4/config/params"
 	"github.com/prysmaticlabs/prysm/v4/crypto/hash"
 	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 	attaggregation "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1/attestation/aggregation/attestations"
@@ -14,20 +16,37 @@ import (
 	"go.opencensus.io/trace"
 )

-// Prepare attestations for fork choice three times per slot.
-var prepareForkChoiceAttsPeriod = slots.DivideSlotBy(3 /* times-per-slot */)
-
 // This prepares fork choice attestations by running batchForkChoiceAtts
 // every prepareForkChoiceAttsPeriod.
 func (s *Service) prepareForkChoiceAtts() {
-	ticker := time.NewTicker(prepareForkChoiceAttsPeriod)
-	defer ticker.Stop()
+	intervals := features.Get().AggregateIntervals
+	slotDuration := time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second
+	// Adjust intervals for networks with a lower slot duration (Hive, e2e, etc)
+	for {
+		if intervals[len(intervals)-1] >= slotDuration {
+			for i, offset := range intervals {
+				intervals[i] = offset / 2
+			}
+		} else {
+			break
+		}
+	}
+	ticker := slots.NewSlotTickerWithIntervals(time.Unix(int64(s.genesisTime), 0), intervals[:])
 	for {
 		select {
-		case <-ticker.C:
+		case slotInterval := <-ticker.C():
+			t := time.Now()
 			if err := s.batchForkChoiceAtts(s.ctx); err != nil {
 				log.WithError(err).Error("Could not prepare attestations for fork choice")
 			}
+			switch slotInterval.Interval {
+			case 0:
+				duration := time.Since(t)
+				log.WithField("Duration", duration).Debug("aggregated unaggregated attestations")
+				batchForkChoiceAttsT1.Observe(float64(duration.Milliseconds()))
+			case 1:
+				batchForkChoiceAttsT2.Observe(float64(time.Since(t).Milliseconds()))
+			}
 		case <-s.ctx.Done():
 			log.Debug("Context closed, exiting routine")
 			return
--- a/Show More
+++ b/Show More
@@ -1 +1 @@
 .1.0
 .3.2