Only process attestations and update head once per slot

Use Epoch boundary cache to retrieve balances (#12083 )
* Use Epoch boundary cache to retrieve balances * save boundary states before inserting to forkchoice * move up last block save * remove boundary checks on balances * fix ordering --------- Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>
2026-01-10 05:47:59 -05:00 · 2023-03-06 22:01:46 -03:00 · 2023-03-06 21:42:47 +00:00 · 2023-03-06 17:01:36 +00:00 · 2023-03-06 09:56:53 +00:00 · 2023-03-05 19:10:41 +00:00
1352 changed files with 73996 additions and 22497 deletions
--- a/.bazelrc
+++ b/.bazelrc
@@ -1,9 +1,9 @@
-# Print warnings for tests with inappropriate test size or timeout.
-test --test_verbose_timeout_warnings
-
-# Only build test targets when running bazel test //...
-test --build_tests_only
-test --test_output=errors
+# Import bazelrc presets
+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/performance.bazelrc

 # E2E run with debug gotag
 test:e2e --define gotags=debug
@@ -11,21 +11,9 @@ test:e2e --define gotags=debug
 # Clearly indicate that coverage is enabled to disable certain nogo checks.
 coverage --define=coverage_enabled=1

-# Fix for rules_docker. See: https://github.com/bazelbuild/rules_docker/issues/842
-build --host_force_python=PY2
-run --host_force_python=PY2
-
-# Networking is blocked for tests by default, add "requires-network" tag to your test if networking
-# is required within the sandbox. Network sandboxing only works on linux.
-build --sandbox_default_allow_network=false
-
 # Stamp binaries with git information
 build --workspace_status_command=./hack/workspace_status.sh

-# Prevent PATH changes from rebuilding when switching from IDE to command line.
-build --incompatible_strict_action_env
-run --incompatible_strict_action_env
-
 build --define blst_disabled=false
 run --define blst_disabled=false

@@ -37,6 +25,7 @@ build:minimal --@io_bazel_rules_go//go/config:tags=minimal

 # Release flags
 build:release --compilation_mode=opt
+build:release --stamp

 # LLVM compiler for building C/C++ dependencies.
 build:llvm --define compiler=llvm
@@ -67,42 +56,6 @@ build:cgo_symbolizer --define=USE_CGO_SYMBOLIZER=true
 build:cgo_symbolizer -c dbg
 build:cgo_symbolizer --define=gotags=cgosymbolizer_enabled

-# multi-arch cross-compiling toolchain configs:
-----------------------------------------------
-build:cross --crosstool_top=@prysm_toolchains//:multiarch_toolchain
-build:cross --host_platform=@io_bazel_rules_go//go/toolchain:linux_amd64
-build:cross --host_crosstool_top=@prysm_toolchains//:hostonly_toolchain
-
-# linux_amd64 config for cross compiler toolchain, not strictly necessary since host/exec env is amd64
-build:linux_amd64 --platforms=@io_bazel_rules_go//go/toolchain:linux_amd64_cgo
-
-# osx_amd64 config for cross compiler toolchain
-build:osx_amd64 --config=cross
-build:osx_amd64 --platforms=@io_bazel_rules_go//go/toolchain:darwin_amd64_cgo
-build:osx_amd64 --compiler=osxcross
-
-# osx_arm64 config for cross compiler toolchain
-build:osx_arm64 --config=cross
-build:osx_arm64 --platforms=@io_bazel_rules_go//go/toolchain:darwin_arm64_cgo
-build:osx_arm64 --compiler=osxcross
-build:osx_arm64 --cpu=aarch64
-
-# windows
-build:windows_amd64 --config=cross
-build:windows_amd64  --platforms=@io_bazel_rules_go//go/toolchain:windows_amd64_cgo
-build:windows_amd64 --compiler=mingw-w64
-
-# linux_arm64 conifg for cross compiler toolchain
-build:linux_arm64 --config=cross
-build:linux_arm64 --platforms=@io_bazel_rules_go//go/toolchain:linux_arm64_cgo
-build:linux_arm64 --copt=-funsafe-math-optimizations
-build:linux_arm64 --copt=-ftree-vectorize
-build:linux_arm64 --copt=-fomit-frame-pointer
-build:linux_arm64 --cpu=aarch64
-build:linux_arm64 --compiler=clang
-build:linux_arm64 --copt=-march=armv8-a
-
-
 # toolchain build debug configs
 #------------------------------
 build:debug --sandbox_debug
@@ -110,123 +63,5 @@ build:debug --toolchain_resolution_debug
 build:debug --verbose_failures
 build:debug -s

-# windows debug
-build:windows_amd64_debug --config=windows_amd64
-build:windows_amd64_debug --config=debug
-
-# osx_amd64 debug config
-build:osx_amd64_debug --config=debug
-build:osx_amd64_debug --config=osx_amd64
-
-# osx_arm64 debug config
-build:osx_arm64_debug --config=debug
-build:osx_arm64_debug --config=osx_arm64
-
-# linux_arm64_debug
-build:linux_arm64_debug --config=linux_arm64
-build:linux_arm64_debug --config=debug
-
-# linux_amd64_debug
-build:linux_amd64_debug --config=linux_amd64
-build:linux_amd64_debug --config=debug
-
-
-# Docker Sandbox Configs
-#-----------------------
-# Note all docker sandbox configs must run from a linux x86_64 host
-# build:docker-sandbox --experimental_docker_image=gcr.io/prysmaticlabs/rbe-worker:latest
-build:docker-sandbox --spawn_strategy=docker --strategy=Javac=docker --genrule_strategy=docker
-build:docker-sandbox --define=EXECUTOR=remote
-build:docker-sandbox --experimental_docker_verbose
-build:docker-sandbox --experimental_enable_docker_sandbox
-build:docker-sandbox --crosstool_top=@rbe_ubuntu_clang//cc:toolchain 
-build:docker-sandbox --host_javabase=@rbe_ubuntu_clang//java:jdk 
-build:docker-sandbox --javabase=@rbe_ubuntu_clang//java:jdk 
-build:docker-sandbox --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_hostjdk8 
-build:docker-sandbox --java_toolchain=@bazel_tools//tools/jdk:toolchain_hostjdk8 
-build:docker-sandbox --extra_execution_platforms=@rbe_ubuntu_clang//config:platform 
-build:docker-sandbox --host_platform=@rbe_ubuntu_clang//config:platform 
-build:docker-sandbox --platforms=@rbe_ubuntu_clang//config:platform
-build:docker-sandbox --extra_toolchains=@prysm_toolchains//:cc-toolchain-multiarch
-
-# windows_amd64 docker sandbox build config
-build:windows_amd64_docker --config=docker-sandbox --config=windows_amd64
-build:windows_amd64_docker_debug --config=windows_amd64_docker --config=debug
-
-# osx_amd64 docker sandbox build config
-build:osx_amd64_docker --config=docker-sandbox --config=osx_amd64
-build:osx_amd64_docker_debug --config=osx_amd64_docker --config=debug
-
-# osx_arm64 docker sandbox build config
-build:osx_arm64_docker --config=docker-sandbox --config=osx_arm64
-build:osx_arm64_docker_debug --config=osx_arm64_docker --config=debug
-
-# linux_arm64 docker sandbox build config
-build:linux_arm64_docker --config=docker-sandbox --config=linux_arm64
-build:linux_arm64_docker_debug --config=linux_arm64_docker --config=debug
-
-# linux_amd64 docker sandbox build config
-build:linux_amd64_docker --config=docker-sandbox --config=linux_amd64
-build:linux_amd64_docker_debug --config=linux_amd64_docker --config=debug
-
-
-# Remote Build Execution
-#-----------------------
-# Originally from https://github.com/bazelbuild/bazel-toolchains/blob/master/bazelrc/bazel-2.0.0.bazelrc
-#
-# Depending on how many machines are in the remote execution instance, setting
-# this higher can make builds faster by allowing more jobs to run in parallel.
-# Setting it too high can result in jobs that timeout, however, while waiting
-# for a remote machine to execute them.
-build:remote --jobs=50
-
-# Set several flags related to specifying the platform, toolchain and java
-# properties.
-# These flags should only be used as is for the rbe-ubuntu16-04 container
-# and need to be adapted to work with other toolchain containers.
-build:remote --host_javabase=@rbe_ubuntu_clang//java:jdk
-build:remote --javabase=@rbe_ubuntu_clang//java:jdk
-build:remote --host_java_toolchain=@bazel_tools//tools/jdk:toolchain_hostjdk8
-build:remote --java_toolchain=@bazel_tools//tools/jdk:toolchain_hostjdk8
-build:remote --crosstool_top=@rbe_ubuntu_clang//cc:toolchain
-build:remote --action_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1
-# Platform flags:
-# The toolchain container used for execution is defined in the target indicated
-# by "extra_execution_platforms", "host_platform" and "platforms".
-# More about platforms: https://docs.bazel.build/versions/master/platforms.html
-build:remote --extra_toolchains=@rbe_ubuntu_clang//config:cc-toolchain
-build:remote --extra_execution_platforms=@rbe_ubuntu_clang//config:platform
-build:remote --host_platform=@rbe_ubuntu_clang//config:platform
-build:remote --platforms=@rbe_ubuntu_clang//config:platform
-
-# Starting with Bazel 0.27.0 strategies do not need to be explicitly
-# defined. See https://github.com/bazelbuild/bazel/issues/7480
-build:remote --define=EXECUTOR=remote
-
-# Enable remote execution so actions are performed on the remote systems.
-# build:remote --remote_executor=grpcs://remotebuildexecution.googleapis.com
-
-# Enforce stricter environment rules, which eliminates some non-hermetic
-# behavior and therefore improves both the remote cache hit rate and the
-# correctness and repeatability of the build.
-build:remote --incompatible_strict_action_env=true
-
-# Set a higher timeout value, just in case.
-build:remote --remote_timeout=3600
-
-# Enable authentication. This will pick up application default credentials by
-# default. You can use --google_credentials=some_file.json to use a service
-# account credential instead.
-# build:remote --google_default_credentials=true
-
-# Enable build without the bytes
-# See: https://github.com/bazelbuild/bazel/issues/6862
-build:remote --experimental_remote_download_outputs=toplevel --experimental_inmemory_jdeps_files --experimental_inmemory_dotd_files
-
-build:remote --remote_local_fallback
-
-# Ignore GoStdLib with remote caching
-build --modify_execution_info='GoStdlib.*=+no-remote-cache'
-
 # Set bazel gotag
 build --define gotags=bazel
--- a/.github/ISSUE_TEMPLATE/feature_request.md
+++ b/.github/ISSUE_TEMPLATE/feature_request.md
@@ -16,12 +16,12 @@ Existing issues often contain information about workarounds, resolution, or prog

 ### Description

-<!-- ✍️--> A clear and concise description of the problem or missing capability...
+<!-- ✍️ A clear and concise description of the problem or missing capability... --> 

 ### Describe the solution you'd like

-<!-- ✍️--> If you have a solution in mind, please describe it.
+<!-- ✍️ If you have a solution in mind, please describe it. --> 

 ### Describe alternatives you've considered

-<!-- ✍️--> Have you considered any alternative solutions or workarounds?
+<!-- ✍️ Have you considered any alternative solutions or workarounds? --> 
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -26,10 +26,10 @@ jobs:
    steps:
      - name: Checkout
        uses: actions/checkout@v2
-      - name: Set up Go 1.18
+      - name: Set up Go 1.19
        uses: actions/setup-go@v3
        with:
-          go-version: 1.18
+          go-version: 1.19
      - name: Run Gosec Security Scanner
        run: | # https://github.com/securego/gosec/issues/469
          export PATH=$PATH:$(go env GOPATH)/bin
@@ -43,16 +43,16 @@ jobs:
      - name: Checkout
        uses: actions/checkout@v2

-      - name: Set up Go 1.18
+      - name: Set up Go 1.19
        uses: actions/setup-go@v3
        with:
-          go-version: 1.18
+          go-version: 1.19
          id: go

      - name: Golangci-lint
        uses: golangci/golangci-lint-action@v3
        with:
-          version: v1.47.2
+          version: v1.50.1
          args: --config=.golangci.yml --out-${NO_FUTURE}format colored-line-number

  build:
@@ -62,7 +62,7 @@ jobs:
      - name: Set up Go 1.x
        uses: actions/setup-go@v2
        with:
-          go-version: 1.18
+          go-version: 1.19
        id: go

      - name: Check out code into the Go module directory
--- a/.gitignore
+++ b/.gitignore
@@ -38,3 +38,6 @@ metaData

 # execution API authentication
 jwt.hex
+
+# manual testing
+tmp
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -6,7 +6,7 @@ run:
    - proto
    - tools/analyzers
  timeout: 10m
-  go: '1.18'
+  go: '1.19'

 linters:
  disable-all: true
--- a/DEPENDENCIES.md
+++ b/DEPENDENCIES.md
@@ -1,4 +1,4 @@
-# Dependency Managagement in Prysm
+# Dependency Management in Prysm

 Prysm is go project with many complicated dependencies, including some c++ based libraries. There
 are two parts to Prysm's dependency management. Go modules and bazel managed dependencies. Be sure 
@@ -28,7 +28,7 @@ including complicated c++ dependencies.
 One key advantage of Bazel over vanilla `go build` is that Bazel automatically (re)builds generated
 pb.go files at build time when file changes are present in any protobuf definition file or after
 any updates to the protobuf compiler or other relevant dependencies. Vanilla go users should run
-the following scripts often to ensure their generated files are up to date. Further more, Prysm
+the following scripts often to ensure their generated files are up to date. Furthermore, Prysm
 generates SSZ marshal related code based on defined data structures. These generated files must
 also be updated and checked in as frequently.

--- a/88
+++ b/88
@@ -76,9 +76,8 @@ http_archive(

 http_archive(
    name = "io_bazel_rules_docker",
-    sha256 = "1f4e59843b61981a96835dc4ac377ad4da9f8c334ebe5e0bb3f58f80c09735f4",
-    strip_prefix = "rules_docker-0.19.0",
-    urls = ["https://github.com/bazelbuild/rules_docker/releases/download/v0.19.0/rules_docker-v0.19.0.tar.gz"],
+    sha256 = "b1e80761a8a8243d03ebca8845e9cc1ba6c82ce7c5179ce2b295cd36f7e394bf",
+    urls = ["https://github.com/bazelbuild/rules_docker/releases/download/v0.25.0/rules_docker-v0.25.0.tar.gz"],
 )

 http_archive(
@@ -88,10 +87,10 @@ http_archive(
        # Expose internals of go_test for custom build transitions.
        "//third_party:io_bazel_rules_go_test.patch",
    ],
-    sha256 = "099a9fb96a376ccbbb7d291ed4ecbdfd42f6bc822ab77ae6f1b5cb9e914e94fa",
+    sha256 = "ae013bf35bd23234d1dea46b079f1e05ba74ac0321423830119d3e787ec73483",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.35.0/rules_go-v0.35.0.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.35.0/rules_go-v0.35.0.zip",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.36.0/rules_go-v0.36.0.zip",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.36.0/rules_go-v0.36.0.zip",
    ],
 )

@@ -110,13 +109,6 @@ git_repository(
    # gazelle args: -go_prefix github.com/gogo/protobuf -proto legacy
 )

-http_archive(
-    name = "fuzzit_linux",
-    build_file_content = "exports_files([\"fuzzit\"])",
-    sha256 = "9ca76ac1c22d9360936006efddf992977ebf8e4788ded8e5f9d511285c9ac774",
-    urls = ["https://github.com/fuzzitdev/fuzzit/releases/download/v2.4.76/fuzzit_Linux_x86_64.zip"],
-)
-
 load(
    "@io_bazel_rules_docker//repositories:repositories.bzl",
    container_repositories = "repositories",
@@ -129,32 +121,36 @@ load(
    "container_pull",
 )

+# Pulled gcr.io/distroless/cc-debian11:latest on 2022-02-23
 container_pull(
-    name = "cc_image_base",
-    digest = "sha256:2c4bb6b7236db0a55ec54ba8845e4031f5db2be957ac61867872bf42e56c4deb",
+    name = "cc_image_base_amd64",
+    digest = "sha256:2a0daf90a7deb78465bfca3ef2eee6e91ce0a5706059f05d79d799a51d339523",
    registry = "gcr.io",
-    repository = "distroless/cc",
+    repository = "distroless/cc-debian11",
 )

+# Pulled gcr.io/distroless/cc-debian11:debug on 2022-02-23
 container_pull(
-    name = "cc_debug_image_base",
-    digest = "sha256:3680c61e81f68fc00bfb5e1ec65e8e678aaafa7c5f056bc2681c29527ebbb30c",
+    name = "cc_debug_image_base_amd64",
+    digest = "sha256:7bd596f5f200588f13a69c268eea6ce428b222b67cd7428d6a7fef95e75c052a",
    registry = "gcr.io",
-    repository = "distroless/cc",
+    repository = "distroless/cc-debian11",
 )

+# Pulled from gcr.io/distroless/base-debian11:latest on 2022-02-23
 container_pull(
-    name = "go_image_base",
-    digest = "sha256:ba7a315f86771332e76fa9c3d423ecfdbb8265879c6f1c264d6fff7d4fa460a4",
+    name = "go_image_base_amd64",
+    digest = "sha256:34e682800774ecbd0954b1663d90238505f1ba5543692dbc75feef7dd4839e90",
    registry = "gcr.io",
-    repository = "distroless/base",
+    repository = "distroless/base-debian11",
 )

+# Pulled from gcr.io/distroless/base-debian11:debug on 2022-02-23
 container_pull(
-    name = "go_debug_image_base",
-    digest = "sha256:efd8711717d9e9b5d0dbb20ea10876dab0609c923bc05321b912f9239090ca80",
+    name = "go_debug_image_base_amd64",
+    digest = "sha256:0f503c6bfd207793bc416f20a35bf6b75d769a903c48f180ad73f60f7b60d7bd",
    registry = "gcr.io",
-    repository = "distroless/base",
+    repository = "distroless/base-debian11",
 )

 container_pull(
@@ -164,35 +160,15 @@ container_pull(
    repository = "pinglamb/alpine-glibc",
 )

-container_pull(
-    name = "fuzzit_base",
-    digest = "sha256:24a39a4360b07b8f0121eb55674a2e757ab09f0baff5569332fefd227ee4338f",
-    registry = "gcr.io",
-    repository = "fuzzit-public/stretch-llvm8",
-)
-
 load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")

 go_rules_dependencies()

 go_register_toolchains(
-    go_version = "1.18.5",
+    go_version = "1.19.4",
    nogo = "@//:nogo",
 )

-http_archive(
-    name = "prysm_testnet_site",
-    build_file_content = """
-proto_library(
-  name = "faucet_proto",
-  srcs = ["src/proto/faucet.proto"],
-  visibility = ["//visibility:public"],
-)""",
-    sha256 = "29742136ff9faf47343073c4569a7cf21b8ed138f726929e09e3c38ab83544f7",
-    strip_prefix = "prysm-testnet-site-5c711600f0a77fc553b18cf37b880eaffef4afdb",
-    url = "https://github.com/prestonvanloon/prysm-testnet-site/archive/5c711600f0a77fc553b18cf37b880eaffef4afdb.tar.gz",
-)
-
 http_archive(
    name = "io_kubernetes_build",
    sha256 = "b84fbd1173acee9d02a7d3698ad269fdf4f7aa081e9cecd40e012ad0ad8cfa2a",
@@ -215,7 +191,7 @@ filegroup(
    url = "https://github.com/eth-clients/slashing-protection-interchange-tests/archive/b8413ca42dc92308019d0d4db52c87e9e125c4e9.tar.gz",
 )

-consensus_spec_version = "v1.2.0"
+consensus_spec_version = "v1.3.0-rc.3"

 bls_test_version = "v0.1.1"

@@ -231,7 +207,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "eded065f923a99b78372d6f748c9b3f1de8229f8f574c1fec9c5fe76c8affb65",
+    sha256 = "c56ea4e8fb2fea4b0b23d2191a87bc7e676738dd8a623b44ac847bfeaae5fe64",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )

@@ -247,7 +223,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "2ed83783129e93360f4bf9d5d5f606ee28adbe8b458acdfac61b8d99218d16a9",
+    sha256 = "c97730b372b81e9ee698c4f09eafaec3fb4be177fab323b32e5ef78d0873fb5c",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )

@@ -263,7 +239,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "f5eff2adac78c99a4180491f373328465263caa2cba0206308a7c598abf76cda",
+    sha256 = "bdd8255c8a536fa83366144aa32fcc3df92a4997401f88f7cda934d13e90d11c",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )

@@ -278,7 +254,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "f1a33b7459391716defa4c2b6f0c1bd7ccc38471ce9126d752d3bad767bebf2b",
+    sha256 = "f6539e19b8e4e45f45b80da39c87dfe7c61d9d7cb51fa7a3a36bdaca11a89693",
    strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
    url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )
@@ -309,9 +285,9 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "82b01a48b143fe0f2fb7fb5f5dd385c1f934335a12d7954f08b1d45d77427b5e",
-    strip_prefix = "eth2-networks-674f7a1d01d9c18345456eab76e3871b3df2126b",
-    url = "https://github.com/eth-clients/eth2-networks/archive/674f7a1d01d9c18345456eab76e3871b3df2126b.tar.gz",
+    sha256 = "2701e1e1a3ec10c673fe7dbdbbe6f02c8ae8c922aebbf6e720d8c72d5458aafe",
+    strip_prefix = "eth2-networks-7b4897888cebef23801540236f73123e21774954",
+    url = "https://github.com/eth-clients/eth2-networks/archive/7b4897888cebef23801540236f73123e21774954.tar.gz",
 )

 http_archive(
@@ -342,9 +318,9 @@ filegroup(
    visibility = ["//visibility:public"],
 )
 """,
-    sha256 = "b2226874526805d64c29e5053fa28e511b57c0860585d6d59777ee81ff4859ca",
+    sha256 = "5006614c33e358699b4e072c649cd4c3866f7d41a691449d5156f6c6e07a4c60",
    urls = [
-        "https://github.com/prysmaticlabs/prysm-web-ui/releases/download/v2.0.2/prysm-web-ui.tar.gz",
+        "https://github.com/prysmaticlabs/prysm-web-ui/releases/download/v2.0.3/prysm-web-ui.tar.gz",
    ],
 )

--- a/api/client/beacon/checkpoint.go
+++ b/api/client/beacon/checkpoint.go
@@ -9,7 +9,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/ssz/detect"
 	"github.com/prysmaticlabs/prysm/v3/io/file"
 	"github.com/prysmaticlabs/prysm/v3/runtime/version"
@@ -18,13 +18,13 @@ import (
 	"golang.org/x/mod/semver"
 )

-// OriginData represents the BeaconState and SignedBeaconBlock necessary to start an empty Beacon Node
+// OriginData represents the BeaconState and ReadOnlySignedBeaconBlock necessary to start an empty Beacon Node
 // using Checkpoint Sync.
 type OriginData struct {
 	sb []byte
 	bb []byte
 	st state.BeaconState
-	b  interfaces.SignedBeaconBlock
+	b  interfaces.ReadOnlySignedBeaconBlock
 	vu *detect.VersionedUnmarshaler
 	br [32]byte
 	sr [32]byte
@@ -49,12 +49,12 @@ func (o *OriginData) StateBytes() []byte {
 	return o.sb
 }

-// BlockBytes returns the ssz-encoded bytes of the downloaded SignedBeaconBlock value.
+// BlockBytes returns the ssz-encoded bytes of the downloaded ReadOnlySignedBeaconBlock value.
 func (o *OriginData) BlockBytes() []byte {
 	return o.bb
 }

-func fname(prefix string, vu *detect.VersionedUnmarshaler, slot types.Slot, root [32]byte) string {
+func fname(prefix string, vu *detect.VersionedUnmarshaler, slot primitives.Slot, root [32]byte) string {
 	return fmt.Sprintf("%s_%s_%s_%d-%#x.ssz", prefix, vu.Config.ConfigName, version.String(vu.Fork), slot, root)
 }

@@ -116,13 +116,13 @@ func DownloadFinalizedData(ctx context.Context, client *Client) (*OriginData, er
 	}, nil
 }

-// WeakSubjectivityData represents the state root, block root and epoch of the BeaconState + SignedBeaconBlock
+// WeakSubjectivityData represents the state root, block root and epoch of the BeaconState + ReadOnlySignedBeaconBlock
 // that falls at the beginning of the current weak subjectivity period. These values can be used to construct
 // a weak subjectivity checkpoint beacon node flag to be used for validation.
 type WeakSubjectivityData struct {
 	BlockRoot [32]byte
 	StateRoot [32]byte
-	Epoch     types.Epoch
+	Epoch     primitives.Epoch
 }

 // CheckpointString returns the standard string representation of a Checkpoint.
@@ -238,7 +238,7 @@ func computeBackwardsCompatible(ctx context.Context, client *Client) (*WeakSubje

 // this method downloads the head state, which can be used to find the correct chain config
 // and use prysm's helper methods to compute the latest weak subjectivity epoch.
-func getWeakSubjectivityEpochFromHead(ctx context.Context, client *Client) (types.Epoch, error) {
+func getWeakSubjectivityEpochFromHead(ctx context.Context, client *Client) (primitives.Epoch, error) {
 	headBytes, err := client.GetState(ctx, IdHead)
 	if err != nil {
 		return 0, err
--- a/api/client/beacon/checkpoint_test.go
+++ b/api/client/beacon/checkpoint_test.go
@@ -19,7 +19,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/time/slots"

 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/ssz/detect"
 	"github.com/prysmaticlabs/prysm/v3/runtime/version"

@@ -102,7 +102,7 @@ func TestFname(t *testing.T) {
 		Config: params.MainnetConfig(),
 		Fork:   version.Phase0,
 	}
-	slot := types.Slot(23)
+	slot := primitives.Slot(23)
 	prefix := "block"
 	var root [32]byte
 	copy(root[:], []byte{0x23, 0x23, 0x23})
@@ -335,7 +335,7 @@ func TestGetWeakSubjectivityEpochFromHead(t *testing.T) {
 	require.Equal(t, expectedEpoch, actualEpoch)
 }

-func forkForEpoch(cfg *params.BeaconChainConfig, epoch types.Epoch) (*ethpb.Fork, error) {
+func forkForEpoch(cfg *params.BeaconChainConfig, epoch primitives.Epoch) (*ethpb.Fork, error) {
 	os := forks.NewOrderedSchedule(cfg)
 	currentVersion, err := os.VersionForEpoch(epoch)
 	if err != nil {
@@ -357,7 +357,7 @@ func forkForEpoch(cfg *params.BeaconChainConfig, epoch types.Epoch) (*ethpb.Fork
 	}, nil
 }

-func defaultTestHeadState(t *testing.T, cfg *params.BeaconChainConfig) (state.BeaconState, types.Epoch) {
+func defaultTestHeadState(t *testing.T, cfg *params.BeaconChainConfig) (state.BeaconState, primitives.Epoch) {
 	st, err := util.NewBeaconStateAltair()
 	require.NoError(t, err)

--- a/api/client/beacon/client.go
+++ b/api/client/beacon/client.go
@@ -21,20 +21,21 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/rpc/apimiddleware"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	log "github.com/sirupsen/logrus"
 )

 const (
-	getSignedBlockPath      = "/eth/v2/beacon/blocks"
-	getBlockRootPath        = "/eth/v1/beacon/blocks/{{.Id}}/root"
-	getForkForStatePath     = "/eth/v1/beacon/states/{{.Id}}/fork"
-	getWeakSubjectivityPath = "/eth/v1/beacon/weak_subjectivity"
-	getForkSchedulePath     = "/eth/v1/config/fork_schedule"
-	getStatePath            = "/eth/v2/debug/beacon/states"
-	getNodeVersionPath      = "/eth/v1/node/version"
+	getSignedBlockPath       = "/eth/v2/beacon/blocks"
+	getBlockRootPath         = "/eth/v1/beacon/blocks/{{.Id}}/root"
+	getForkForStatePath      = "/eth/v1/beacon/states/{{.Id}}/fork"
+	getWeakSubjectivityPath  = "/eth/v1/beacon/weak_subjectivity"
+	getForkSchedulePath      = "/eth/v1/config/fork_schedule"
+	getStatePath             = "/eth/v2/debug/beacon/states"
+	getNodeVersionPath       = "/eth/v1/node/version"
+	changeBLStoExecutionPath = "/eth/v1/beacon/pool/bls_to_execution_changes"
 )

 // StateOrBlockId represents the block_id / state_id parameters that several of the Eth Beacon API methods accept.
@@ -61,7 +62,7 @@ func IdFromRoot(r [32]byte) StateOrBlockId {

 // IdFromSlot encodes a Slot in the format expected by the API in places where a slot can be used to identify
 // a BeaconState or SignedBeaconBlock.
-func IdFromSlot(s types.Slot) StateOrBlockId {
+func IdFromSlot(s primitives.Slot) StateOrBlockId {
 	return StateOrBlockId(strconv.FormatUint(uint64(s), 10))
 }

@@ -146,7 +147,6 @@ func withSSZEncoding() reqOption {
 // 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})
-	log.Printf("requesting %s", u.String())
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
 	if err != nil {
 		return nil, err
@@ -337,12 +337,66 @@ func (c *Client) GetWeakSubjectivity(ctx context.Context) (*WeakSubjectivityData
 		return nil, err
 	}
 	return &WeakSubjectivityData{
-		Epoch:     types.Epoch(epoch),
+		Epoch:     primitives.Epoch(epoch),
 		BlockRoot: bytesutil.ToBytes32(blockRoot),
 		StateRoot: bytesutil.ToBytes32(stateRoot),
 	}, nil
 }

+// 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})
+	body, err := json.Marshal(request)
+	if err != nil {
+		return errors.Wrap(err, "failed to marshal JSON")
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, u.String(), bytes.NewBuffer(body))
+	if err != nil {
+		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)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		err = resp.Body.Close()
+	}()
+	if resp.StatusCode != http.StatusOK {
+		decoder := json.NewDecoder(resp.Body)
+		decoder.DisallowUnknownFields()
+		errorJson := &apimiddleware.IndexedVerificationFailureErrorJson{}
+		if err := decoder.Decode(errorJson); err != nil {
+			return errors.Wrapf(err, "failed to decode error JSON for %s", resp.Request.URL)
+		}
+		for _, failure := range errorJson.Failures {
+			w := request[failure.Index].Message
+			log.WithFields(log.Fields{
+				"validator_index":    w.ValidatorIndex,
+				"withdrawal_address": w.ToExecutionAddress,
+			}).Error(failure.Message)
+		}
+		return errors.Errorf("POST error %d: %s", errorJson.Code, errorJson.Message)
+	}
+	return nil
+}
+
+// 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)
+	if err != nil {
+		return nil, err
+	}
+	poolResponse := &apimiddleware.BLSToExecutionChangesPoolResponseJson{}
+	err = json.Unmarshal(body, poolResponse)
+	if err != nil {
+		return nil, err
+	}
+	return poolResponse, nil
+}
+
 func non200Err(response *http.Response) error {
 	bodyBytes, err := io.ReadAll(response.Body)
 	var body string
@@ -388,7 +442,7 @@ func (f *forkResponse) Fork() (*ethpb.Fork, error) {
 	return &ethpb.Fork{
 		CurrentVersion:  cSlice,
 		PreviousVersion: pSlice,
-		Epoch:           types.Epoch(epoch),
+		Epoch:           primitives.Epoch(epoch),
 	}, nil
 }

@@ -413,7 +467,7 @@ func (fsr *forkScheduleResponse) OrderedForkSchedule() (forks.OrderedSchedule, e
 		version := bytesutil.ToBytes4(vSlice)
 		ofs = append(ofs, forks.ForkScheduleEntry{
 			Version: version,
-			Epoch:   types.Epoch(uint64(epoch)),
+			Epoch:   primitives.Epoch(uint64(epoch)),
 		})
 	}
 	sort.Sort(ofs)
--- a/api/client/beacon/doc.go
+++ b/api/client/beacon/doc.go
@@ -1,6 +1,5 @@
 /*
 Package beacon provides a client for interacting with the standard Eth Beacon Node API.
 Interactive swagger documentation for the API is available here: https://ethereum.github.io/beacon-APIs/
-
 */
 package beacon
--- a/api/client/builder/BUILD.bazel
+++ b/api/client/builder/BUILD.bazel
@@ -3,6 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
    name = "go_default_library",
    srcs = [
+        "bid.go",
        "client.go",
        "errors.go",
        "types.go",
@@ -10,6 +11,8 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/v3/api/client/builder",
    visibility = ["//visibility:public"],
    deps = [
+        "//consensus-types/blocks:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//encoding/bytesutil:go_default_library",
        "//monitoring/tracing:go_default_library",
@@ -17,8 +20,10 @@ go_library(
        "//network/authorization:go_default_library",
        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
+        "//runtime/version:go_default_library",
        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
+        "@com_github_prysmaticlabs_fastssz//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
    ],
@@ -34,10 +39,12 @@ go_test(
    embed = [":go_default_library"],
    deps = [
        "//config/params:go_default_library",
+        "//consensus-types/blocks:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//encoding/bytesutil:go_default_library",
        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
+        "//testing/assert:go_default_library",
        "//testing/require:go_default_library",
        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
        "@com_github_golang_protobuf//proto:go_default_library",
--- a/api/client/builder/bid.go
+++ b/api/client/builder/bid.go
@@ -0,0 +1,195 @@
+package builder
+
+import (
+	"math/big"
+
+	ssz "github.com/prysmaticlabs/fastssz"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/runtime/version"
+)
+
+// SignedBid is an interface describing the method set of a signed builder bid.
+type SignedBid interface {
+	Message() (Bid, error)
+	Signature() []byte
+	Version() int
+	IsNil() bool
+}
+
+// Bid is an interface describing the method set of a builder bid.
+type Bid interface {
+	Header() (interfaces.ExecutionData, error)
+	Value() []byte
+	Pubkey() []byte
+	Version() int
+	IsNil() bool
+	HashTreeRoot() ([32]byte, error)
+	HashTreeRootWith(hh *ssz.Hasher) error
+}
+
+type signedBuilderBid struct {
+	p *ethpb.SignedBuilderBid
+}
+
+// WrappedSignedBuilderBid is a constructor which wraps a protobuf signed bit into an interface.
+func WrappedSignedBuilderBid(p *ethpb.SignedBuilderBid) (SignedBid, error) {
+	w := signedBuilderBid{p: p}
+	if w.IsNil() {
+		return nil, blocks.ErrNilObjectWrapped
+	}
+	return w, nil
+}
+
+// Message --
+func (b signedBuilderBid) Message() (Bid, error) {
+	return WrappedBuilderBid(b.p.Message)
+}
+
+// Signature --
+func (b signedBuilderBid) Signature() []byte {
+	return b.p.Signature
+}
+
+// Version --
+func (b signedBuilderBid) Version() int {
+	return version.Bellatrix
+}
+
+// IsNil --
+func (b signedBuilderBid) IsNil() bool {
+	return b.p == nil
+}
+
+type signedBuilderBidCapella struct {
+	p *ethpb.SignedBuilderBidCapella
+}
+
+// WrappedSignedBuilderBidCapella is a constructor which wraps a protobuf signed bit into an interface.
+func WrappedSignedBuilderBidCapella(p *ethpb.SignedBuilderBidCapella) (SignedBid, error) {
+	w := signedBuilderBidCapella{p: p}
+	if w.IsNil() {
+		return nil, blocks.ErrNilObjectWrapped
+	}
+	return w, nil
+}
+
+// Message --
+func (b signedBuilderBidCapella) Message() (Bid, error) {
+	return WrappedBuilderBidCapella(b.p.Message)
+}
+
+// Signature --
+func (b signedBuilderBidCapella) Signature() []byte {
+	return b.p.Signature
+}
+
+// Version --
+func (b signedBuilderBidCapella) Version() int {
+	return version.Capella
+}
+
+// IsNil --
+func (b signedBuilderBidCapella) IsNil() bool {
+	return b.p == nil
+}
+
+type builderBid struct {
+	p *ethpb.BuilderBid
+}
+
+// WrappedBuilderBid is a constructor which wraps a protobuf bid into an interface.
+func WrappedBuilderBid(p *ethpb.BuilderBid) (Bid, error) {
+	w := builderBid{p: p}
+	if w.IsNil() {
+		return nil, blocks.ErrNilObjectWrapped
+	}
+	return w, nil
+}
+
+// Header --
+func (b builderBid) Header() (interfaces.ExecutionData, error) {
+	return blocks.WrappedExecutionPayloadHeader(b.p.Header)
+}
+
+// Version --
+func (b builderBid) Version() int {
+	return version.Bellatrix
+}
+
+// Value --
+func (b builderBid) Value() []byte {
+	return b.p.Value
+}
+
+// Pubkey --
+func (b builderBid) Pubkey() []byte {
+	return b.p.Pubkey
+}
+
+// IsNil --
+func (b builderBid) IsNil() bool {
+	return b.p == nil
+}
+
+// HashTreeRoot --
+func (b builderBid) HashTreeRoot() ([32]byte, error) {
+	return b.p.HashTreeRoot()
+}
+
+// HashTreeRootWith --
+func (b builderBid) HashTreeRootWith(hh *ssz.Hasher) error {
+	return b.p.HashTreeRootWith(hh)
+}
+
+type builderBidCapella struct {
+	p *ethpb.BuilderBidCapella
+}
+
+// WrappedBuilderBidCapella is a constructor which wraps a protobuf bid into an interface.
+func WrappedBuilderBidCapella(p *ethpb.BuilderBidCapella) (Bid, error) {
+	w := builderBidCapella{p: p}
+	if w.IsNil() {
+		return nil, blocks.ErrNilObjectWrapped
+	}
+	return w, nil
+}
+
+// Header returns the execution data interface.
+func (b builderBidCapella) Header() (interfaces.ExecutionData, error) {
+	// We have to convert big endian to little endian because the value is coming from the execution layer.
+	v := bytesutil.ReverseByteOrder(b.p.Value)
+	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header, big.NewInt(0).SetBytes(v))
+}
+
+// Version --
+func (b builderBidCapella) Version() int {
+	return version.Capella
+}
+
+// Value --
+func (b builderBidCapella) Value() []byte {
+	return b.p.Value
+}
+
+// Pubkey --
+func (b builderBidCapella) Pubkey() []byte {
+	return b.p.Pubkey
+}
+
+// IsNil --
+func (b builderBidCapella) IsNil() bool {
+	return b.p == nil
+}
+
+// HashTreeRoot --
+func (b builderBidCapella) HashTreeRoot() ([32]byte, error) {
+	return b.p.HashTreeRoot()
+}
+
+// HashTreeRootWith --
+func (b builderBidCapella) HashTreeRootWith(hh *ssz.Hasher) error {
+	return b.p.HashTreeRootWith(hh)
+}
--- a/api/client/builder/client.go
+++ b/api/client/builder/client.go
@@ -6,19 +6,23 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"math/big"
 	"net"
 	"net/http"
 	"net/url"
+	"strings"
 	"text/template"
 	"time"

 	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/monitoring/tracing"
 	"github.com/prysmaticlabs/prysm/v3/network"
 	"github.com/prysmaticlabs/prysm/v3/network/authorization"
-	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/runtime/version"
 	log "github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )
@@ -32,6 +36,7 @@ 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)
@@ -82,9 +87,9 @@ var _ observer = &requestLogger{}
 // BuilderClient provides a collection of helper methods for calling Builder API endpoints.
 type BuilderClient interface {
 	NodeURL() string
-	GetHeader(ctx context.Context, slot types.Slot, parentHash [32]byte, pubkey [48]byte) (*ethpb.SignedBuilderBid, error)
+	GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubkey [48]byte) (SignedBid, error)
 	RegisterValidator(ctx context.Context, svr []*ethpb.SignedValidatorRegistrationV1) error
-	SubmitBlindedBlock(ctx context.Context, sb *ethpb.SignedBlindedBeaconBlockBellatrix) (*v1.ExecutionPayload, error)
+	SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, error)
 	Status(ctx context.Context) error
 }

@@ -184,9 +189,9 @@ func (c *Client) do(ctx context.Context, method string, path string, body io.Rea

 var execHeaderTemplate = template.Must(template.New("").Parse(getExecHeaderPath))

-func execHeaderPath(slot types.Slot, parentHash [32]byte, pubkey [48]byte) (string, error) {
+func execHeaderPath(slot primitives.Slot, parentHash [32]byte, pubkey [48]byte) (string, error) {
 	v := struct {
-		Slot       types.Slot
+		Slot       primitives.Slot
 		ParentHash string
 		Pubkey     string
 	}{
@@ -202,8 +207,8 @@ func execHeaderPath(slot types.Slot, parentHash [32]byte, pubkey [48]byte) (stri
 	return b.String(), nil
 }

-// GetHeader is used by a proposing validator to request an ExecutionPayloadHeader from the Builder node.
-func (c *Client) GetHeader(ctx context.Context, slot types.Slot, parentHash [32]byte, pubkey [48]byte) (*ethpb.SignedBuilderBid, error) {
+// GetHeader is used by a proposing validator to request an execution payload header from the Builder node.
+func (c *Client) GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubkey [48]byte) (SignedBid, error) {
 	path, err := execHeaderPath(slot, parentHash, pubkey)
 	if err != nil {
 		return nil, err
@@ -212,11 +217,35 @@ func (c *Client) GetHeader(ctx context.Context, slot types.Slot, parentHash [32]
 	if err != nil {
 		return nil, err
 	}
-	hr := &ExecHeaderResponse{}
-	if err := json.Unmarshal(hb, hr); err != nil {
+	v := &VersionResponse{}
+	if err := json.Unmarshal(hb, v); err != nil {
 		return nil, errors.Wrapf(err, "error unmarshaling the builder GetHeader response, using slot=%d, parentHash=%#x, pubkey=%#x", slot, parentHash, pubkey)
 	}
-	return hr.ToProto()
+	switch strings.ToLower(v.Version) {
+	case strings.ToLower(version.String(version.Capella)):
+		hr := &ExecHeaderResponseCapella{}
+		if err := json.Unmarshal(hb, hr); err != nil {
+			return nil, errors.Wrapf(err, "error unmarshaling the builder GetHeader response, using slot=%d, parentHash=%#x, pubkey=%#x", slot, parentHash, pubkey)
+		}
+		p, err := hr.ToProto()
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not extract proto message from header")
+		}
+		return WrappedSignedBuilderBidCapella(p)
+	case strings.ToLower(version.String(version.Bellatrix)):
+		hr := &ExecHeaderResponse{}
+		if err := json.Unmarshal(hb, hr); err != nil {
+			return nil, errors.Wrapf(err, "error unmarshaling the builder GetHeader response, using slot=%d, parentHash=%#x, pubkey=%#x", slot, parentHash, pubkey)
+		}
+		p, err := hr.ToProto()
+		if err != nil {
+			return nil, errors.Wrap(err, "could not extract proto message from header")
+		}
+		return WrappedSignedBuilderBid(p)
+	default:
+		return nil, fmt.Errorf("unsupported header version %s", strings.ToLower(v.Version))
+	}
+
 }

 // RegisterValidator encodes the SignedValidatorRegistrationV1 message to json (including hex-encoding the byte
@@ -247,26 +276,75 @@ func (c *Client) RegisterValidator(ctx context.Context, svr []*ethpb.SignedValid
 }

 // SubmitBlindedBlock calls the builder API endpoint that binds the validator to the builder and submits the block.
-// The response is the full ExecutionPayload used to create the blinded block.
-func (c *Client) SubmitBlindedBlock(ctx context.Context, sb *ethpb.SignedBlindedBeaconBlockBellatrix) (*v1.ExecutionPayload, error) {
-	v := &SignedBlindedBeaconBlockBellatrix{SignedBlindedBeaconBlockBellatrix: sb}
-	body, err := json.Marshal(v)
-	if err != nil {
-		return nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockBellatrix value body in SubmitBlindedBlock")
+// The response is the full execution payload used to create the blinded block.
+func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, error) {
+	if !sb.IsBlinded() {
+		return nil, errNotBlinded
 	}
+	switch sb.Version() {
+	case version.Bellatrix:
+		psb, err := sb.PbBlindedBellatrixBlock()
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not get protobuf block")
+		}
+		b := &SignedBlindedBeaconBlockBellatrix{SignedBlindedBeaconBlockBellatrix: psb}
+		body, err := json.Marshal(b)
+		if err != nil {
+			return nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockBellatrix value body in SubmitBlindedBlock")
+		}

-	ctx, cancel := context.WithTimeout(ctx, submitBlindedBlockTimeout)
-	defer cancel()
-	rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body))
+		ctx, cancel := context.WithTimeout(ctx, submitBlindedBlockTimeout)
+		defer cancel()
+		versionOpt := func(r *http.Request) {
+			r.Header.Add("Eth-Consensus-Version", version.String(version.Bellatrix))
+		}
+		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)

-	if err != nil {
-		return nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockBellatrix to the builder api")
+		if err != nil {
+			return nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockBellatrix to the builder api")
+		}
+		ep := &ExecPayloadResponse{}
+		if err := json.Unmarshal(rb, ep); err != nil {
+			return nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlock response")
+		}
+		p, err := ep.ToProto()
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not extract proto message from payload")
+		}
+		return blocks.WrappedExecutionPayload(p)
+	case version.Capella:
+		psb, err := sb.PbBlindedCapellaBlock()
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not get protobuf block")
+		}
+		b := &SignedBlindedBeaconBlockCapella{SignedBlindedBeaconBlockCapella: psb}
+		body, err := json.Marshal(b)
+		if err != nil {
+			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))
+		}
+		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)
+
+		if err != nil {
+			return nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockCapella to the builder api")
+		}
+		ep := &ExecPayloadResponseCapella{}
+		if err := json.Unmarshal(rb, ep); err != nil {
+			return nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlockCapella response")
+		}
+		p, err := ep.ToProto()
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not extract proto message from payload")
+		}
+		return blocks.WrappedExecutionPayloadCapella(p, big.NewInt(0))
+	default:
+		return nil, fmt.Errorf("unsupported block version %s", version.String(sb.Version()))
 	}
-	ep := &ExecPayloadResponse{}
-	if err := json.Unmarshal(rb, ep); err != nil {
-		return nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlock response")
-	}
-	return ep.ToProto()
 }

 // Status asks the remote builder server for a health check. A response of 200 with an empty body is the success/healthy
--- a/api/client/builder/client_test.go
+++ b/api/client/builder/client_test.go
@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"math/big"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -13,10 +14,12 @@ import (

 	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	eth "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/testing/assert"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 )

@@ -81,7 +84,7 @@ func TestClient_Status(t *testing.T) {

 func TestClient_RegisterValidator(t *testing.T) {
 	ctx := context.Background()
-	expectedBody := `[{"message":{"fee_recipient":"0x0000000000000000000000000000000000000000","gas_limit":"23","timestamp":"42","pubkey":"0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"}}]`
+	expectedBody := `[{"message":{"fee_recipient":"0x0000000000000000000000000000000000000000","gas_limit":"23","timestamp":"42","pubkey":"0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"},"signature":"0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"}]`
 	expectedPath := "/eth/v1/builder/validators"
 	hc := &http.Client{
 		Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
@@ -111,6 +114,7 @@ func TestClient_RegisterValidator(t *testing.T) {
 			Timestamp:    42,
 			Pubkey:       ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
 		},
+		Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
 	}
 	require.NoError(t, c.RegisterValidator(ctx, []*eth.SignedValidatorRegistrationV1{reg}))
 }
@@ -118,99 +122,203 @@ func TestClient_RegisterValidator(t *testing.T) {
 func TestClient_GetHeader(t *testing.T) {
 	ctx := context.Background()
 	expectedPath := "/eth/v1/builder/header/23/0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2/0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
-	hc := &http.Client{
-		Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-			require.Equal(t, expectedPath, r.URL.Path)
-			message := ErrorMessage{
-				Code:    500,
-				Message: "Internal server error",
-			}
-			resp, err := json.Marshal(message)
-			require.NoError(t, err)
-			return &http.Response{
-				StatusCode: http.StatusInternalServerError,
-				Body:       io.NopCloser(bytes.NewBuffer(resp)),
-				Request:    r.Clone(ctx),
-			}, nil
-		}),
-	}
-	c := &Client{
-		hc:      hc,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
 	var slot types.Slot = 23
 	parentHash := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
 	pubkey := ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
-	_, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
-	require.ErrorIs(t, err, ErrNotOK)

-	hc = &http.Client{
-		Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-			require.Equal(t, expectedPath, r.URL.Path)
-			return &http.Response{
-				StatusCode: http.StatusNoContent,
-				Body:       io.NopCloser(bytes.NewBuffer([]byte("No header is available."))),
-				Request:    r.Clone(ctx),
-			}, nil
-		}),
-	}
-	c = &Client{
-		hc:      hc,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
-	_, err = c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
-	require.ErrorIs(t, err, ErrNoContent)
+	t.Run("server error", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, expectedPath, r.URL.Path)
+				message := ErrorMessage{
+					Code:    500,
+					Message: "Internal server error",
+				}
+				resp, err := json.Marshal(message)
+				require.NoError(t, err)
+				return &http.Response{
+					StatusCode: http.StatusInternalServerError,
+					Body:       io.NopCloser(bytes.NewBuffer(resp)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}

-	hc = &http.Client{
-		Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-			require.Equal(t, expectedPath, r.URL.Path)
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponse)),
-				Request:    r.Clone(ctx),
-			}, nil
-		}),
-	}
-	c = &Client{
-		hc:      hc,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
-	h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
-	require.NoError(t, err)
-	expectedSig := ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505")
-	require.Equal(t, true, bytes.Equal(expectedSig, h.Signature))
-	expectedTxRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
-	require.Equal(t, true, bytes.Equal(expectedTxRoot, h.Message.Header.TransactionsRoot))
-	require.Equal(t, uint64(1), h.Message.Header.GasUsed)
-	value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
-	require.NoError(t, err)
-	require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", h.Message.Value))
+		_, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.ErrorIs(t, err, ErrNotOK)
+	})
+	t.Run("header not available", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, expectedPath, r.URL.Path)
+				return &http.Response{
+					StatusCode: http.StatusNoContent,
+					Body:       io.NopCloser(bytes.NewBuffer([]byte("No header is available."))),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		_, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.ErrorIs(t, err, ErrNoContent)
+	})
+	t.Run("bellatrix", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, expectedPath, r.URL.Path)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponse)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.NoError(t, err)
+		expectedSig := ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505")
+		require.Equal(t, true, bytes.Equal(expectedSig, h.Signature()))
+		expectedTxRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+		bid, err := h.Message()
+		require.NoError(t, err)
+		bidHeader, err := bid.Header()
+		require.NoError(t, err)
+		withdrawalsRoot, err := bidHeader.TransactionsRoot()
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(expectedTxRoot, withdrawalsRoot))
+		require.Equal(t, uint64(1), bidHeader.GasUsed())
+		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
+		require.NoError(t, err)
+		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
+		bidValue := bytesutil.ReverseByteOrder(bid.Value())
+		require.DeepEqual(t, bidValue, value.Bytes())
+		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
+	})
+	t.Run("capella", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, expectedPath, r.URL.Path)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponseCapella)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		h, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.NoError(t, err)
+		expectedWithdrawalsRoot := ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+		bid, err := h.Message()
+		require.NoError(t, err)
+		bidHeader, err := bid.Header()
+		require.NoError(t, err)
+		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
+		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
+		require.NoError(t, err)
+		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
+		bidValue := bytesutil.ReverseByteOrder(bid.Value())
+		require.DeepEqual(t, bidValue, value.Bytes())
+		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
+	})
+	t.Run("unsupported version", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, expectedPath, r.URL.Path)
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponseUnknownVersion)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		_, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
+		require.ErrorContains(t, "unsupported header version", err)
+	})
 }

 func TestSubmitBlindedBlock(t *testing.T) {
 	ctx := context.Background()
-	hc := &http.Client{
-		Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-			require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayload)),
-				Request:    r.Clone(ctx),
-			}, nil
-		}),
-	}
-	c := &Client{
-		hc:      hc,
-		baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-	}
-	sbbb := testSignedBlindedBeaconBlockBellatrix(t)
-	ep, err := c.SubmitBlindedBlock(ctx, sbbb)
-	require.NoError(t, err)
-	require.Equal(t, true, bytes.Equal(ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"), ep.ParentHash))
-	bfpg, err := stringToUint256("452312848583266388373324160190187140051835877600158453279131187530910662656")
-	require.NoError(t, err)
-	require.Equal(t, fmt.Sprintf("%#x", bfpg.SSZBytes()), fmt.Sprintf("%#x", ep.BaseFeePerGas))
-	require.Equal(t, uint64(1), ep.GasLimit)
+
+	t.Run("bellatrix", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, "bellatrix", r.Header.Get("Eth-Consensus-Version"))
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayload)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
+		require.NoError(t, err)
+		ep, err := c.SubmitBlindedBlock(ctx, sbbb)
+		require.NoError(t, err)
+		require.Equal(t, true, bytes.Equal(ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"), ep.ParentHash()))
+		bfpg, err := stringToUint256("452312848583266388373324160190187140051835877600158453279131187530910662656")
+		require.NoError(t, err)
+		require.Equal(t, fmt.Sprintf("%#x", bfpg.SSZBytes()), fmt.Sprintf("%#x", ep.BaseFeePerGas()))
+		require.Equal(t, uint64(1), ep.GasLimit())
+	})
+	t.Run("capella", func(t *testing.T) {
+		hc := &http.Client{
+			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
+				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, "capella", r.Header.Get("Eth-Consensus-Version"))
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayloadCapella)),
+					Request:    r.Clone(ctx),
+				}, nil
+			}),
+		}
+		c := &Client{
+			hc:      hc,
+			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
+		}
+		sbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockCapella(t))
+		require.NoError(t, err)
+		ep, err := c.SubmitBlindedBlock(ctx, sbb)
+		require.NoError(t, err)
+		withdrawals, err := ep.Withdrawals()
+		require.NoError(t, err)
+		require.Equal(t, 1, len(withdrawals))
+		assert.Equal(t, uint64(1), withdrawals[0].Index)
+		assert.Equal(t, types.ValidatorIndex(1), withdrawals[0].ValidatorIndex)
+		assert.DeepEqual(t, ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943"), withdrawals[0].Address)
+		assert.Equal(t, uint64(1), withdrawals[0].Amount)
+	})
+	t.Run("not blinded", func(t *testing.T) {
+		sbb, err := blocks.NewSignedBeaconBlock(&eth.SignedBeaconBlockBellatrix{Block: &eth.BeaconBlockBellatrix{Body: &eth.BeaconBlockBodyBellatrix{}}})
+		require.NoError(t, err)
+		_, err = (&Client{}).SubmitBlindedBlock(ctx, sbb)
+		require.ErrorIs(t, err, errNotBlinded)
+	})
 }

 func testSignedBlindedBeaconBlockBellatrix(t *testing.T) *eth.SignedBlindedBeaconBlockBellatrix {
@@ -355,6 +463,149 @@ func testSignedBlindedBeaconBlockBellatrix(t *testing.T) *eth.SignedBlindedBeaco
 	}
 }

+func testSignedBlindedBeaconBlockCapella(t *testing.T) *eth.SignedBlindedBeaconBlockCapella {
+	return &eth.SignedBlindedBeaconBlockCapella{
+		Block: &eth.BlindedBeaconBlockCapella{
+			Slot:          1,
+			ProposerIndex: 1,
+			ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+			StateRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+			Body: &eth.BlindedBeaconBlockBodyCapella{
+				RandaoReveal: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+				Eth1Data: &eth.Eth1Data{
+					DepositRoot:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					DepositCount: 1,
+					BlockHash:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+				},
+				Graffiti: ezDecode(t, "0xdeadbeefc0ffee"),
+				ProposerSlashings: []*eth.ProposerSlashing{
+					{
+						Header_1: &eth.SignedBeaconBlockHeader{
+							Header: &eth.BeaconBlockHeader{
+								Slot:          1,
+								ProposerIndex: 1,
+								ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								StateRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								BodyRoot:      ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+						Header_2: &eth.SignedBeaconBlockHeader{
+							Header: &eth.BeaconBlockHeader{
+								Slot:          1,
+								ProposerIndex: 1,
+								ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								StateRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								BodyRoot:      ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+					},
+				},
+				AttesterSlashings: []*eth.AttesterSlashing{
+					{
+						Attestation_1: &eth.IndexedAttestation{
+							AttestingIndices: []uint64{1},
+							Data: &eth.AttestationData{
+								Slot:            1,
+								CommitteeIndex:  1,
+								BeaconBlockRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								Source: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+								Target: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+						Attestation_2: &eth.IndexedAttestation{
+							AttestingIndices: []uint64{1},
+							Data: &eth.AttestationData{
+								Slot:            1,
+								CommitteeIndex:  1,
+								BeaconBlockRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								Source: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+								Target: &eth.Checkpoint{
+									Epoch: 1,
+									Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+								},
+							},
+							Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+					},
+				},
+				Attestations: []*eth.Attestation{
+					{
+						AggregationBits: bitfield.Bitlist{0x01},
+						Data: &eth.AttestationData{
+							Slot:            1,
+							CommitteeIndex:  1,
+							BeaconBlockRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							Source: &eth.Checkpoint{
+								Epoch: 1,
+								Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+							Target: &eth.Checkpoint{
+								Epoch: 1,
+								Root:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							},
+						},
+						Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+					},
+				},
+				Deposits: []*eth.Deposit{
+					{
+						Proof: [][]byte{ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")},
+						Data: &eth.Deposit_Data{
+							PublicKey:             ezDecode(t, "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"),
+							WithdrawalCredentials: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+							Amount:                1,
+							Signature:             ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+						},
+					},
+				},
+				VoluntaryExits: []*eth.SignedVoluntaryExit{
+					{
+						Exit: &eth.VoluntaryExit{
+							Epoch:          1,
+							ValidatorIndex: 1,
+						},
+						Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+					},
+				},
+				SyncAggregate: &eth.SyncAggregate{
+					SyncCommitteeSignature: make([]byte, 48),
+					SyncCommitteeBits:      bitfield.Bitvector512{0x01},
+				},
+				ExecutionPayloadHeader: &v1.ExecutionPayloadHeaderCapella{
+					ParentHash:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					FeeRecipient:     ezDecode(t, "0xabcf8e0d4e9587369b2301d0790347320302cc09"),
+					StateRoot:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					ReceiptsRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					LogsBloom:        ezDecode(t, "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
+					PrevRandao:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					BlockNumber:      1,
+					GasLimit:         1,
+					GasUsed:          1,
+					Timestamp:        1,
+					ExtraData:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					BaseFeePerGas:    []byte(strconv.FormatUint(1, 10)),
+					BlockHash:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					TransactionsRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+					WithdrawalsRoot:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+				},
+			},
+		},
+		Signature: ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+	}
+}
+
 func TestRequestLogger(t *testing.T) {
 	wo := WithObserver(&requestLogger{})
 	c, err := NewClient("localhost:3500", wo)
--- a/api/client/builder/testdata/blinded-block-capella.json
+++ b/api/client/builder/testdata/blinded-block-capella.json
--- a/api/client/builder/testdata/execution-payload-capella.json
+++ b/api/client/builder/testdata/execution-payload-capella.json
@@ -0,0 +1 @@
+{"parent_hash":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","fee_recipient":"0xabcf8e0d4e9587369b2301d0790347320302cc09","state_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","receipts_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","logs_bloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","prev_randao":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","block_number":"1","gas_limit":"1","gas_used":"1","timestamp":"1","extra_data":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","base_fee_per_gas":"14074904626401341155369551180448584754667373453244490859944217516317499064576","block_hash":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","transactions_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","withdrawals_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"}
--- a/api/client/builder/testing/BUILD.bazel
+++ b/api/client/builder/testing/BUILD.bazel
@@ -6,9 +6,10 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/v3/api/client/builder/testing",
    visibility = ["//visibility:public"],
    deps = [
+        "//api/client/builder:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//encoding/bytesutil:go_default_library",
-        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
    ],
 )
--- a/api/client/builder/testing/mock.go
+++ b/api/client/builder/testing/mock.go
@@ -3,9 +3,10 @@ package testing
 import (
 	"context"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/api/client/builder"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 )

@@ -25,7 +26,7 @@ func (MockClient) NodeURL() string {
 }

 // GetHeader --
-func (MockClient) GetHeader(_ context.Context, _ types.Slot, _ [32]byte, _ [48]byte) (*ethpb.SignedBuilderBid, error) {
+func (MockClient) GetHeader(_ context.Context, _ primitives.Slot, _ [32]byte, _ [48]byte) (builder.SignedBid, error) {
 	return nil, nil
 }

@@ -39,7 +40,7 @@ func (m MockClient) RegisterValidator(_ context.Context, svr []*ethpb.SignedVali
 }

 // SubmitBlindedBlock --
-func (MockClient) SubmitBlindedBlock(_ context.Context, _ *ethpb.SignedBlindedBeaconBlockBellatrix) (*v1.ExecutionPayload, error) {
+func (MockClient) SubmitBlindedBlock(_ context.Context, _ interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, error) {
 	return nil, nil
 }

--- a/api/client/builder/types.go
+++ b/api/client/builder/types.go
@@ -8,6 +8,7 @@ import (

 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	eth "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
@@ -23,8 +24,8 @@ type ValidatorRegistration struct {

 func (r *SignedValidatorRegistration) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Message   *ValidatorRegistration `json:"message,omitempty"`
-		Signature hexutil.Bytes          `json:"signature,omitempty"`
+		Message   *ValidatorRegistration `json:"message"`
+		Signature hexutil.Bytes          `json:"signature"`
 	}{
 		Message:   &ValidatorRegistration{r.Message},
 		Signature: r.SignedValidatorRegistrationV1.Signature,
@@ -36,8 +37,8 @@ func (r *SignedValidatorRegistration) UnmarshalJSON(b []byte) error {
 		r.SignedValidatorRegistrationV1 = &eth.SignedValidatorRegistrationV1{}
 	}
 	o := struct {
-		Message   *ValidatorRegistration `json:"message,omitempty"`
-		Signature hexutil.Bytes          `json:"signature,omitempty"`
+		Message   *ValidatorRegistration `json:"message"`
+		Signature hexutil.Bytes          `json:"signature"`
 	}{}
 	if err := json.Unmarshal(b, &o); err != nil {
 		return err
@@ -49,10 +50,10 @@ func (r *SignedValidatorRegistration) UnmarshalJSON(b []byte) error {

 func (r *ValidatorRegistration) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		FeeRecipient hexutil.Bytes `json:"fee_recipient,omitempty"`
-		GasLimit     string        `json:"gas_limit,omitempty"`
-		Timestamp    string        `json:"timestamp,omitempty"`
-		Pubkey       hexutil.Bytes `json:"pubkey,omitempty"`
+		FeeRecipient hexutil.Bytes `json:"fee_recipient"`
+		GasLimit     string        `json:"gas_limit"`
+		Timestamp    string        `json:"timestamp"`
+		Pubkey       hexutil.Bytes `json:"pubkey"`
 	}{
 		FeeRecipient: r.FeeRecipient,
 		GasLimit:     fmt.Sprintf("%d", r.GasLimit),
@@ -66,10 +67,10 @@ func (r *ValidatorRegistration) UnmarshalJSON(b []byte) error {
 		r.ValidatorRegistrationV1 = &eth.ValidatorRegistrationV1{}
 	}
 	o := struct {
-		FeeRecipient hexutil.Bytes `json:"fee_recipient,omitempty"`
-		GasLimit     string        `json:"gas_limit,omitempty"`
-		Timestamp    string        `json:"timestamp,omitempty"`
-		Pubkey       hexutil.Bytes `json:"pubkey,omitempty"`
+		FeeRecipient hexutil.Bytes `json:"fee_recipient"`
+		GasLimit     string        `json:"gas_limit"`
+		Timestamp    string        `json:"timestamp"`
+		Pubkey       hexutil.Bytes `json:"pubkey"`
 	}{}
 	if err := json.Unmarshal(b, &o); err != nil {
 		return err
@@ -110,8 +111,7 @@ func stringToUint256(s string) (Uint256, error) {

 // sszBytesToUint256 creates a Uint256 from a ssz-style (little-endian byte slice) representation.
 func sszBytesToUint256(b []byte) (Uint256, error) {
-	bi := new(big.Int)
-	bi.SetBytes(bytesutil.ReverseByteOrder(b))
+	bi := bytesutil.LittleEndianBytesToBigInt(b)
 	if !isValidUint256(bi) {
 		return Uint256{}, errors.Wrapf(errDecodeUint256, "value=%s", b)
 	}
@@ -182,12 +182,16 @@ func (s Uint64String) MarshalText() ([]byte, error) {
 	return []byte(fmt.Sprintf("%d", s)), nil
 }

+type VersionResponse struct {
+	Version string `json:"version"`
+}
+
 type ExecHeaderResponse struct {
-	Version string `json:"version,omitempty"`
+	Version string `json:"version"`
 	Data    struct {
-		Signature hexutil.Bytes `json:"signature,omitempty"`
-		Message   *BuilderBid   `json:"message,omitempty"`
-	} `json:"data,omitempty"`
+		Signature hexutil.Bytes `json:"signature"`
+		Message   *BuilderBid   `json:"message"`
+	} `json:"data"`
 }

 func (ehr *ExecHeaderResponse) ToProto() (*eth.SignedBuilderBid, error) {
@@ -233,26 +237,26 @@ func (h *ExecutionPayloadHeader) ToProto() (*v1.ExecutionPayloadHeader, error) {
 }

 type BuilderBid struct {
-	Header *ExecutionPayloadHeader `json:"header,omitempty"`
-	Value  Uint256                 `json:"value,omitempty"`
-	Pubkey hexutil.Bytes           `json:"pubkey,omitempty"`
+	Header *ExecutionPayloadHeader `json:"header"`
+	Value  Uint256                 `json:"value"`
+	Pubkey hexutil.Bytes           `json:"pubkey"`
 }

 type ExecutionPayloadHeader struct {
-	ParentHash       hexutil.Bytes `json:"parent_hash,omitempty"`
-	FeeRecipient     hexutil.Bytes `json:"fee_recipient,omitempty"`
-	StateRoot        hexutil.Bytes `json:"state_root,omitempty"`
-	ReceiptsRoot     hexutil.Bytes `json:"receipts_root,omitempty"`
-	LogsBloom        hexutil.Bytes `json:"logs_bloom,omitempty"`
-	PrevRandao       hexutil.Bytes `json:"prev_randao,omitempty"`
-	BlockNumber      Uint64String  `json:"block_number,omitempty"`
-	GasLimit         Uint64String  `json:"gas_limit,omitempty"`
-	GasUsed          Uint64String  `json:"gas_used,omitempty"`
-	Timestamp        Uint64String  `json:"timestamp,omitempty"`
-	ExtraData        hexutil.Bytes `json:"extra_data,omitempty"`
-	BaseFeePerGas    Uint256       `json:"base_fee_per_gas,omitempty"`
-	BlockHash        hexutil.Bytes `json:"block_hash,omitempty"`
-	TransactionsRoot hexutil.Bytes `json:"transactions_root,omitempty"`
+	ParentHash       hexutil.Bytes `json:"parent_hash"`
+	FeeRecipient     hexutil.Bytes `json:"fee_recipient"`
+	StateRoot        hexutil.Bytes `json:"state_root"`
+	ReceiptsRoot     hexutil.Bytes `json:"receipts_root"`
+	LogsBloom        hexutil.Bytes `json:"logs_bloom"`
+	PrevRandao       hexutil.Bytes `json:"prev_randao"`
+	BlockNumber      Uint64String  `json:"block_number"`
+	GasLimit         Uint64String  `json:"gas_limit"`
+	GasUsed          Uint64String  `json:"gas_used"`
+	Timestamp        Uint64String  `json:"timestamp"`
+	ExtraData        hexutil.Bytes `json:"extra_data"`
+	BaseFeePerGas    Uint256       `json:"base_fee_per_gas"`
+	BlockHash        hexutil.Bytes `json:"block_hash"`
+	TransactionsRoot hexutil.Bytes `json:"transactions_root"`
 	*v1.ExecutionPayloadHeader
 }

@@ -294,25 +298,25 @@ func (h *ExecutionPayloadHeader) UnmarshalJSON(b []byte) error {
 }

 type ExecPayloadResponse struct {
-	Version string           `json:"version,omitempty"`
-	Data    ExecutionPayload `json:"data,omitempty"`
+	Version string           `json:"version"`
+	Data    ExecutionPayload `json:"data"`
 }

 type ExecutionPayload struct {
-	ParentHash    hexutil.Bytes   `json:"parent_hash,omitempty"`
-	FeeRecipient  hexutil.Bytes   `json:"fee_recipient,omitempty"`
-	StateRoot     hexutil.Bytes   `json:"state_root,omitempty"`
-	ReceiptsRoot  hexutil.Bytes   `json:"receipts_root,omitempty"`
-	LogsBloom     hexutil.Bytes   `json:"logs_bloom,omitempty"`
-	PrevRandao    hexutil.Bytes   `json:"prev_randao,omitempty"`
-	BlockNumber   Uint64String    `json:"block_number,omitempty"`
-	GasLimit      Uint64String    `json:"gas_limit,omitempty"`
-	GasUsed       Uint64String    `json:"gas_used,omitempty"`
-	Timestamp     Uint64String    `json:"timestamp,omitempty"`
-	ExtraData     hexutil.Bytes   `json:"extra_data,omitempty"`
-	BaseFeePerGas Uint256         `json:"base_fee_per_gas,omitempty"`
-	BlockHash     hexutil.Bytes   `json:"block_hash,omitempty"`
-	Transactions  []hexutil.Bytes `json:"transactions,omitempty"`
+	ParentHash    hexutil.Bytes   `json:"parent_hash"`
+	FeeRecipient  hexutil.Bytes   `json:"fee_recipient"`
+	StateRoot     hexutil.Bytes   `json:"state_root"`
+	ReceiptsRoot  hexutil.Bytes   `json:"receipts_root"`
+	LogsBloom     hexutil.Bytes   `json:"logs_bloom"`
+	PrevRandao    hexutil.Bytes   `json:"prev_randao"`
+	BlockNumber   Uint64String    `json:"block_number"`
+	GasLimit      Uint64String    `json:"gas_limit"`
+	GasUsed       Uint64String    `json:"gas_used"`
+	Timestamp     Uint64String    `json:"timestamp"`
+	ExtraData     hexutil.Bytes   `json:"extra_data"`
+	BaseFeePerGas Uint256         `json:"base_fee_per_gas"`
+	BlockHash     hexutil.Bytes   `json:"block_hash"`
+	Transactions  []hexutil.Bytes `json:"transactions"`
 }

 func (r *ExecPayloadResponse) ToProto() (*v1.ExecutionPayload, error) {
@@ -342,6 +346,186 @@ func (p *ExecutionPayload) ToProto() (*v1.ExecutionPayload, error) {
 	}, nil
 }

+type ExecHeaderResponseCapella struct {
+	Data struct {
+		Signature hexutil.Bytes      `json:"signature"`
+		Message   *BuilderBidCapella `json:"message"`
+	} `json:"data"`
+}
+
+func (ehr *ExecHeaderResponseCapella) ToProto() (*eth.SignedBuilderBidCapella, error) {
+	bb, err := ehr.Data.Message.ToProto()
+	if err != nil {
+		return nil, err
+	}
+	return &eth.SignedBuilderBidCapella{
+		Message:   bb,
+		Signature: ehr.Data.Signature,
+	}, nil
+}
+
+func (bb *BuilderBidCapella) ToProto() (*eth.BuilderBidCapella, error) {
+	header, err := bb.Header.ToProto()
+	if err != nil {
+		return nil, err
+	}
+	return &eth.BuilderBidCapella{
+		Header: header,
+		Value:  bb.Value.SSZBytes(),
+		Pubkey: bb.Pubkey,
+	}, nil
+}
+
+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,
+		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,
+	}, nil
+}
+
+type BuilderBidCapella struct {
+	Header *ExecutionPayloadHeaderCapella `json:"header"`
+	Value  Uint256                        `json:"value"`
+	Pubkey hexutil.Bytes                  `json:"pubkey"`
+}
+
+type ExecutionPayloadHeaderCapella struct {
+	ParentHash       hexutil.Bytes `json:"parent_hash"`
+	FeeRecipient     hexutil.Bytes `json:"fee_recipient"`
+	StateRoot        hexutil.Bytes `json:"state_root"`
+	ReceiptsRoot     hexutil.Bytes `json:"receipts_root"`
+	LogsBloom        hexutil.Bytes `json:"logs_bloom"`
+	PrevRandao       hexutil.Bytes `json:"prev_randao"`
+	BlockNumber      Uint64String  `json:"block_number"`
+	GasLimit         Uint64String  `json:"gas_limit"`
+	GasUsed          Uint64String  `json:"gas_used"`
+	Timestamp        Uint64String  `json:"timestamp"`
+	ExtraData        hexutil.Bytes `json:"extra_data"`
+	BaseFeePerGas    Uint256       `json:"base_fee_per_gas"`
+	BlockHash        hexutil.Bytes `json:"block_hash"`
+	TransactionsRoot hexutil.Bytes `json:"transactions_root"`
+	WithdrawalsRoot  hexutil.Bytes `json:"withdrawals_root"`
+	*v1.ExecutionPayloadHeaderCapella
+}
+
+func (h *ExecutionPayloadHeaderCapella) MarshalJSON() ([]byte, error) {
+	type MarshalCaller ExecutionPayloadHeaderCapella
+	baseFeePerGas, err := sszBytesToUint256(h.ExecutionPayloadHeaderCapella.BaseFeePerGas)
+	if err != nil {
+		return []byte{}, errors.Wrapf(err, "invalid BaseFeePerGas")
+	}
+	return json.Marshal(&MarshalCaller{
+		ParentHash:       h.ExecutionPayloadHeaderCapella.ParentHash,
+		FeeRecipient:     h.ExecutionPayloadHeaderCapella.FeeRecipient,
+		StateRoot:        h.ExecutionPayloadHeaderCapella.StateRoot,
+		ReceiptsRoot:     h.ExecutionPayloadHeaderCapella.ReceiptsRoot,
+		LogsBloom:        h.ExecutionPayloadHeaderCapella.LogsBloom,
+		PrevRandao:       h.ExecutionPayloadHeaderCapella.PrevRandao,
+		BlockNumber:      Uint64String(h.ExecutionPayloadHeaderCapella.BlockNumber),
+		GasLimit:         Uint64String(h.ExecutionPayloadHeaderCapella.GasLimit),
+		GasUsed:          Uint64String(h.ExecutionPayloadHeaderCapella.GasUsed),
+		Timestamp:        Uint64String(h.ExecutionPayloadHeaderCapella.Timestamp),
+		ExtraData:        h.ExecutionPayloadHeaderCapella.ExtraData,
+		BaseFeePerGas:    baseFeePerGas,
+		BlockHash:        h.ExecutionPayloadHeaderCapella.BlockHash,
+		TransactionsRoot: h.ExecutionPayloadHeaderCapella.TransactionsRoot,
+		WithdrawalsRoot:  h.ExecutionPayloadHeaderCapella.WithdrawalsRoot,
+	})
+}
+
+func (h *ExecutionPayloadHeaderCapella) UnmarshalJSON(b []byte) error {
+	type UnmarshalCaller ExecutionPayloadHeaderCapella
+	uc := &UnmarshalCaller{}
+	if err := json.Unmarshal(b, uc); err != nil {
+		return err
+	}
+	ep := ExecutionPayloadHeaderCapella(*uc)
+	*h = ep
+	var err error
+	h.ExecutionPayloadHeaderCapella, err = h.ToProto()
+	return err
+}
+
+type ExecPayloadResponseCapella struct {
+	Version string                  `json:"version"`
+	Data    ExecutionPayloadCapella `json:"data"`
+}
+
+type ExecutionPayloadCapella struct {
+	ParentHash    hexutil.Bytes   `json:"parent_hash"`
+	FeeRecipient  hexutil.Bytes   `json:"fee_recipient"`
+	StateRoot     hexutil.Bytes   `json:"state_root"`
+	ReceiptsRoot  hexutil.Bytes   `json:"receipts_root"`
+	LogsBloom     hexutil.Bytes   `json:"logs_bloom"`
+	PrevRandao    hexutil.Bytes   `json:"prev_randao"`
+	BlockNumber   Uint64String    `json:"block_number"`
+	GasLimit      Uint64String    `json:"gas_limit"`
+	GasUsed       Uint64String    `json:"gas_used"`
+	Timestamp     Uint64String    `json:"timestamp"`
+	ExtraData     hexutil.Bytes   `json:"extra_data"`
+	BaseFeePerGas Uint256         `json:"base_fee_per_gas"`
+	BlockHash     hexutil.Bytes   `json:"block_hash"`
+	Transactions  []hexutil.Bytes `json:"transactions"`
+	Withdrawals   []Withdrawal    `json:"withdrawals"`
+}
+
+func (r *ExecPayloadResponseCapella) ToProto() (*v1.ExecutionPayloadCapella, error) {
+	return r.Data.ToProto()
+}
+
+func (p *ExecutionPayloadCapella) ToProto() (*v1.ExecutionPayloadCapella, error) {
+	txs := make([][]byte, len(p.Transactions))
+	for i := range p.Transactions {
+		txs[i] = 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,
+			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,
+		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,
+		Transactions:  txs,
+		Withdrawals:   withdrawals,
+	}, nil
+}
+
+type Withdrawal struct {
+	Index          Uint256       `json:"index"`
+	ValidatorIndex Uint256       `json:"validator_index"`
+	Address        hexutil.Bytes `json:"address"`
+	Amount         Uint256       `json:"amount"`
+}
+
 type SignedBlindedBeaconBlockBellatrix struct {
 	*eth.SignedBlindedBeaconBlockBellatrix
 }
@@ -356,8 +540,8 @@ type BlindedBeaconBlockBodyBellatrix struct {

 func (r *SignedBlindedBeaconBlockBellatrix) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Message   *BlindedBeaconBlockBellatrix `json:"message,omitempty"`
-		Signature hexutil.Bytes                `json:"signature,omitempty"`
+		Message   *BlindedBeaconBlockBellatrix `json:"message"`
+		Signature hexutil.Bytes                `json:"signature"`
 	}{
 		Message:   &BlindedBeaconBlockBellatrix{r.SignedBlindedBeaconBlockBellatrix.Block},
 		Signature: r.SignedBlindedBeaconBlockBellatrix.Signature,
@@ -367,10 +551,10 @@ func (r *SignedBlindedBeaconBlockBellatrix) MarshalJSON() ([]byte, error) {
 func (b *BlindedBeaconBlockBellatrix) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Slot          string                           `json:"slot"`
-		ProposerIndex string                           `json:"proposer_index,omitempty"`
-		ParentRoot    hexutil.Bytes                    `json:"parent_root,omitempty"`
-		StateRoot     hexutil.Bytes                    `json:"state_root,omitempty"`
-		Body          *BlindedBeaconBlockBodyBellatrix `json:"body,omitempty"`
+		ProposerIndex string                           `json:"proposer_index"`
+		ParentRoot    hexutil.Bytes                    `json:"parent_root"`
+		StateRoot     hexutil.Bytes                    `json:"state_root"`
+		Body          *BlindedBeaconBlockBodyBellatrix `json:"body"`
 	}{
 		Slot:          fmt.Sprintf("%d", b.Slot),
 		ProposerIndex: fmt.Sprintf("%d", b.ProposerIndex),
@@ -386,8 +570,8 @@ type ProposerSlashing struct {

 func (s *ProposerSlashing) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		SignedHeader1 *SignedBeaconBlockHeader `json:"signed_header_1,omitempty"`
-		SignedHeader2 *SignedBeaconBlockHeader `json:"signed_header_2,omitempty"`
+		SignedHeader1 *SignedBeaconBlockHeader `json:"signed_header_1"`
+		SignedHeader2 *SignedBeaconBlockHeader `json:"signed_header_2"`
 	}{
 		SignedHeader1: &SignedBeaconBlockHeader{s.ProposerSlashing.Header_1},
 		SignedHeader2: &SignedBeaconBlockHeader{s.ProposerSlashing.Header_2},
@@ -400,8 +584,8 @@ type SignedBeaconBlockHeader struct {

 func (h *SignedBeaconBlockHeader) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Header    *BeaconBlockHeader `json:"message,omitempty"`
-		Signature hexutil.Bytes      `json:"signature,omitempty"`
+		Header    *BeaconBlockHeader `json:"message"`
+		Signature hexutil.Bytes      `json:"signature"`
 	}{
 		Header:    &BeaconBlockHeader{h.SignedBeaconBlockHeader.Header},
 		Signature: h.SignedBeaconBlockHeader.Signature,
@@ -414,11 +598,11 @@ type BeaconBlockHeader struct {

 func (h *BeaconBlockHeader) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Slot          string        `json:"slot,omitempty"`
-		ProposerIndex string        `json:"proposer_index,omitempty"`
-		ParentRoot    hexutil.Bytes `json:"parent_root,omitempty"`
-		StateRoot     hexutil.Bytes `json:"state_root,omitempty"`
-		BodyRoot      hexutil.Bytes `json:"body_root,omitempty"`
+		Slot          string        `json:"slot"`
+		ProposerIndex string        `json:"proposer_index"`
+		ParentRoot    hexutil.Bytes `json:"parent_root"`
+		StateRoot     hexutil.Bytes `json:"state_root"`
+		BodyRoot      hexutil.Bytes `json:"body_root"`
 	}{
 		Slot:          fmt.Sprintf("%d", h.BeaconBlockHeader.Slot),
 		ProposerIndex: fmt.Sprintf("%d", h.BeaconBlockHeader.ProposerIndex),
@@ -438,9 +622,9 @@ func (a *IndexedAttestation) MarshalJSON() ([]byte, error) {
 		indices[i] = fmt.Sprintf("%d", a.AttestingIndices[i])
 	}
 	return json.Marshal(struct {
-		AttestingIndices []string         `json:"attesting_indices,omitempty"`
-		Data             *AttestationData `json:"data,omitempty"`
-		Signature        hexutil.Bytes    `json:"signature,omitempty"`
+		AttestingIndices []string         `json:"attesting_indices"`
+		Data             *AttestationData `json:"data"`
+		Signature        hexutil.Bytes    `json:"signature"`
 	}{
 		AttestingIndices: indices,
 		Data:             &AttestationData{a.IndexedAttestation.Data},
@@ -454,8 +638,8 @@ type AttesterSlashing struct {

 func (s *AttesterSlashing) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Attestation1 *IndexedAttestation `json:"attestation_1,omitempty"`
-		Attestation2 *IndexedAttestation `json:"attestation_2,omitempty"`
+		Attestation1 *IndexedAttestation `json:"attestation_1"`
+		Attestation2 *IndexedAttestation `json:"attestation_2"`
 	}{
 		Attestation1: &IndexedAttestation{s.Attestation_1},
 		Attestation2: &IndexedAttestation{s.Attestation_2},
@@ -468,8 +652,8 @@ type Checkpoint struct {

 func (c *Checkpoint) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Epoch string        `json:"epoch,omitempty"`
-		Root  hexutil.Bytes `json:"root,omitempty"`
+		Epoch string        `json:"epoch"`
+		Root  hexutil.Bytes `json:"root"`
 	}{
 		Epoch: fmt.Sprintf("%d", c.Checkpoint.Epoch),
 		Root:  c.Checkpoint.Root,
@@ -482,11 +666,11 @@ type AttestationData struct {

 func (a *AttestationData) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Slot            string        `json:"slot,omitempty"`
-		Index           string        `json:"index,omitempty"`
-		BeaconBlockRoot hexutil.Bytes `json:"beacon_block_root,omitempty"`
-		Source          *Checkpoint   `json:"source,omitempty"`
-		Target          *Checkpoint   `json:"target,omitempty"`
+		Slot            string        `json:"slot"`
+		Index           string        `json:"index"`
+		BeaconBlockRoot hexutil.Bytes `json:"beacon_block_root"`
+		Source          *Checkpoint   `json:"source"`
+		Target          *Checkpoint   `json:"target"`
 	}{
 		Slot:            fmt.Sprintf("%d", a.AttestationData.Slot),
 		Index:           fmt.Sprintf("%d", a.AttestationData.CommitteeIndex),
@@ -502,9 +686,9 @@ type Attestation struct {

 func (a *Attestation) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		AggregationBits hexutil.Bytes    `json:"aggregation_bits,omitempty"`
-		Data            *AttestationData `json:"data,omitempty"`
-		Signature       hexutil.Bytes    `json:"signature,omitempty" ssz-size:"96"`
+		AggregationBits hexutil.Bytes    `json:"aggregation_bits"`
+		Data            *AttestationData `json:"data"`
+		Signature       hexutil.Bytes    `json:"signature" ssz-size:"96"`
 	}{
 		AggregationBits: hexutil.Bytes(a.Attestation.AggregationBits),
 		Data:            &AttestationData{a.Attestation.Data},
@@ -518,10 +702,10 @@ type DepositData struct {

 func (d *DepositData) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		PublicKey             hexutil.Bytes `json:"pubkey,omitempty"`
-		WithdrawalCredentials hexutil.Bytes `json:"withdrawal_credentials,omitempty"`
-		Amount                string        `json:"amount,omitempty"`
-		Signature             hexutil.Bytes `json:"signature,omitempty"`
+		PublicKey             hexutil.Bytes `json:"pubkey"`
+		WithdrawalCredentials hexutil.Bytes `json:"withdrawal_credentials"`
+		Amount                string        `json:"amount"`
+		Signature             hexutil.Bytes `json:"signature"`
 	}{
 		PublicKey:             d.PublicKey,
 		WithdrawalCredentials: d.WithdrawalCredentials,
@@ -554,8 +738,8 @@ type SignedVoluntaryExit struct {

 func (sve *SignedVoluntaryExit) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Message   *VoluntaryExit `json:"message,omitempty"`
-		Signature hexutil.Bytes  `json:"signature,omitempty"`
+		Message   *VoluntaryExit `json:"message"`
+		Signature hexutil.Bytes  `json:"signature"`
 	}{
 		Signature: sve.SignedVoluntaryExit.Signature,
 		Message:   &VoluntaryExit{sve.SignedVoluntaryExit.Exit},
@@ -568,8 +752,8 @@ type VoluntaryExit struct {

 func (ve *VoluntaryExit) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		Epoch          string `json:"epoch,omitempty"`
-		ValidatorIndex string `json:"validator_index,omitempty"`
+		Epoch          string `json:"epoch"`
+		ValidatorIndex string `json:"validator_index"`
 	}{
 		Epoch:          fmt.Sprintf("%d", ve.Epoch),
 		ValidatorIndex: fmt.Sprintf("%d", ve.ValidatorIndex),
@@ -582,8 +766,8 @@ type SyncAggregate struct {

 func (s *SyncAggregate) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		SyncCommitteeBits      hexutil.Bytes `json:"sync_committee_bits,omitempty"`
-		SyncCommitteeSignature hexutil.Bytes `json:"sync_committee_signature,omitempty"`
+		SyncCommitteeBits      hexutil.Bytes `json:"sync_committee_bits"`
+		SyncCommitteeSignature hexutil.Bytes `json:"sync_committee_signature"`
 	}{
 		SyncCommitteeBits:      hexutil.Bytes(s.SyncAggregate.SyncCommitteeBits),
 		SyncCommitteeSignature: s.SyncAggregate.SyncCommitteeSignature,
@@ -596,9 +780,9 @@ type Eth1Data struct {

 func (e *Eth1Data) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
-		DepositRoot  hexutil.Bytes `json:"deposit_root,omitempty"`
-		DepositCount string        `json:"deposit_count,omitempty"`
-		BlockHash    hexutil.Bytes `json:"block_hash,omitempty"`
+		DepositRoot  hexutil.Bytes `json:"deposit_root"`
+		DepositCount string        `json:"deposit_count"`
+		BlockHash    hexutil.Bytes `json:"block_hash"`
 	}{
 		DepositRoot:  e.DepositRoot,
 		DepositCount: fmt.Sprintf("%d", e.DepositCount),
@@ -628,16 +812,16 @@ func (b *BlindedBeaconBlockBodyBellatrix) MarshalJSON() ([]byte, error) {
 		pros[i] = &ProposerSlashing{ProposerSlashing: b.BlindedBeaconBlockBodyBellatrix.ProposerSlashings[i]}
 	}
 	return json.Marshal(struct {
-		RandaoReveal           hexutil.Bytes           `json:"randao_reveal,omitempty"`
-		Eth1Data               *Eth1Data               `json:"eth1_data,omitempty"`
-		Graffiti               hexutil.Bytes           `json:"graffiti,omitempty"`
-		ProposerSlashings      []*ProposerSlashing     `json:"proposer_slashings,omitempty"`
-		AttesterSlashings      []*AttesterSlashing     `json:"attester_slashings,omitempty"`
-		Attestations           []*Attestation          `json:"attestations,omitempty"`
-		Deposits               []*Deposit              `json:"deposits,omitempty"`
-		VoluntaryExits         []*SignedVoluntaryExit  `json:"voluntary_exits,omitempty"`
-		SyncAggregate          *SyncAggregate          `json:"sync_aggregate,omitempty"`
-		ExecutionPayloadHeader *ExecutionPayloadHeader `json:"execution_payload_header,omitempty"`
+		RandaoReveal           hexutil.Bytes           `json:"randao_reveal"`
+		Eth1Data               *Eth1Data               `json:"eth1_data"`
+		Graffiti               hexutil.Bytes           `json:"graffiti"`
+		ProposerSlashings      []*ProposerSlashing     `json:"proposer_slashings"`
+		AttesterSlashings      []*AttesterSlashing     `json:"attester_slashings"`
+		Attestations           []*Attestation          `json:"attestations"`
+		Deposits               []*Deposit              `json:"deposits"`
+		VoluntaryExits         []*SignedVoluntaryExit  `json:"voluntary_exits"`
+		SyncAggregate          *SyncAggregate          `json:"sync_aggregate"`
+		ExecutionPayloadHeader *ExecutionPayloadHeader `json:"execution_payload_header"`
 	}{
 		RandaoReveal:           b.RandaoReveal,
 		Eth1Data:               &Eth1Data{b.BlindedBeaconBlockBodyBellatrix.Eth1Data},
@@ -652,6 +836,126 @@ func (b *BlindedBeaconBlockBodyBellatrix) MarshalJSON() ([]byte, error) {
 	})
 }

+type SignedBLSToExecutionChange struct {
+	*eth.SignedBLSToExecutionChange
+}
+
+func (ch *SignedBLSToExecutionChange) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Message   *BLSToExecutionChange `json:"message"`
+		Signature hexutil.Bytes         `json:"signature"`
+	}{
+		Signature: ch.Signature,
+		Message:   &BLSToExecutionChange{ch.Message},
+	})
+}
+
+type BLSToExecutionChange struct {
+	*eth.BLSToExecutionChange
+}
+
+func (ch *BLSToExecutionChange) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		ValidatorIndex     string        `json:"validator_index"`
+		FromBlsPubkey      hexutil.Bytes `json:"from_bls_pubkey"`
+		ToExecutionAddress hexutil.Bytes `json:"to_execution_address"`
+	}{
+		ValidatorIndex:     fmt.Sprintf("%d", ch.ValidatorIndex),
+		FromBlsPubkey:      ch.FromBlsPubkey,
+		ToExecutionAddress: ch.ToExecutionAddress,
+	})
+}
+
+type SignedBlindedBeaconBlockCapella struct {
+	*eth.SignedBlindedBeaconBlockCapella
+}
+
+type BlindedBeaconBlockCapella struct {
+	*eth.BlindedBeaconBlockCapella
+}
+
+type BlindedBeaconBlockBodyCapella struct {
+	*eth.BlindedBeaconBlockBodyCapella
+}
+
+func (b *SignedBlindedBeaconBlockCapella) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Message   *BlindedBeaconBlockCapella `json:"message"`
+		Signature hexutil.Bytes              `json:"signature"`
+	}{
+		Message:   &BlindedBeaconBlockCapella{b.Block},
+		Signature: b.Signature,
+	})
+}
+
+func (b *BlindedBeaconBlockCapella) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Slot          string                         `json:"slot"`
+		ProposerIndex string                         `json:"proposer_index"`
+		ParentRoot    hexutil.Bytes                  `json:"parent_root"`
+		StateRoot     hexutil.Bytes                  `json:"state_root"`
+		Body          *BlindedBeaconBlockBodyCapella `json:"body"`
+	}{
+		Slot:          fmt.Sprintf("%d", b.Slot),
+		ProposerIndex: fmt.Sprintf("%d", b.ProposerIndex),
+		ParentRoot:    b.ParentRoot,
+		StateRoot:     b.StateRoot,
+		Body:          &BlindedBeaconBlockBodyCapella{b.Body},
+	})
+}
+
+func (b *BlindedBeaconBlockBodyCapella) MarshalJSON() ([]byte, error) {
+	sve := make([]*SignedVoluntaryExit, len(b.VoluntaryExits))
+	for i := range b.VoluntaryExits {
+		sve[i] = &SignedVoluntaryExit{SignedVoluntaryExit: b.VoluntaryExits[i]}
+	}
+	deps := make([]*Deposit, len(b.Deposits))
+	for i := range b.Deposits {
+		deps[i] = &Deposit{Deposit: b.Deposits[i]}
+	}
+	atts := make([]*Attestation, len(b.Attestations))
+	for i := range b.Attestations {
+		atts[i] = &Attestation{Attestation: b.Attestations[i]}
+	}
+	atsl := make([]*AttesterSlashing, len(b.AttesterSlashings))
+	for i := range b.AttesterSlashings {
+		atsl[i] = &AttesterSlashing{AttesterSlashing: b.AttesterSlashings[i]}
+	}
+	pros := make([]*ProposerSlashing, len(b.ProposerSlashings))
+	for i := range b.ProposerSlashings {
+		pros[i] = &ProposerSlashing{ProposerSlashing: b.ProposerSlashings[i]}
+	}
+	chs := make([]*SignedBLSToExecutionChange, len(b.BlsToExecutionChanges))
+	for i := range b.BlsToExecutionChanges {
+		chs[i] = &SignedBLSToExecutionChange{SignedBLSToExecutionChange: b.BlsToExecutionChanges[i]}
+	}
+	return json.Marshal(struct {
+		RandaoReveal           hexutil.Bytes                  `json:"randao_reveal"`
+		Eth1Data               *Eth1Data                      `json:"eth1_data"`
+		Graffiti               hexutil.Bytes                  `json:"graffiti"`
+		ProposerSlashings      []*ProposerSlashing            `json:"proposer_slashings"`
+		AttesterSlashings      []*AttesterSlashing            `json:"attester_slashings"`
+		Attestations           []*Attestation                 `json:"attestations"`
+		Deposits               []*Deposit                     `json:"deposits"`
+		VoluntaryExits         []*SignedVoluntaryExit         `json:"voluntary_exits"`
+		BLSToExecutionChanges  []*SignedBLSToExecutionChange  `json:"bls_to_execution_changes"`
+		SyncAggregate          *SyncAggregate                 `json:"sync_aggregate"`
+		ExecutionPayloadHeader *ExecutionPayloadHeaderCapella `json:"execution_payload_header"`
+	}{
+		RandaoReveal:           b.RandaoReveal,
+		Eth1Data:               &Eth1Data{b.Eth1Data},
+		Graffiti:               b.Graffiti,
+		ProposerSlashings:      pros,
+		AttesterSlashings:      atsl,
+		Attestations:           atts,
+		Deposits:               deps,
+		VoluntaryExits:         sve,
+		BLSToExecutionChanges:  chs,
+		SyncAggregate:          &SyncAggregate{b.SyncAggregate},
+		ExecutionPayloadHeader: &ExecutionPayloadHeaderCapella{ExecutionPayloadHeaderCapella: b.ExecutionPayloadHeader},
+	})
+}
+
 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
@@ -16,6 +16,7 @@ import (
 	"github.com/prysmaticlabs/go-bitfield"
 	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	eth "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/testing/assert"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 )

@@ -87,6 +88,62 @@ var testExampleHeaderResponse = `{
  }
 }`

+var testExampleHeaderResponseCapella = `{
+  "version": "capella",
+  "data": {
+    "message": {
+      "header": {
+        "parent_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "fee_recipient": "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+        "state_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "receipts_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "logs_bloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "prev_randao": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "block_number": "1",
+        "gas_limit": "1",
+        "gas_used": "1",
+        "timestamp": "1",
+        "extra_data": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "base_fee_per_gas": "452312848583266388373324160190187140051835877600158453279131187530910662656",
+        "block_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "transactions_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "withdrawals_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"
+      },
+      "value": "652312848583266388373324160190187140051835877600158453279131187530910662656",
+      "pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
+    },
+    "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
+  }
+}`
+
+var testExampleHeaderResponseUnknownVersion = `{
+  "version": "bad",
+  "data": {
+    "message": {
+      "header": {
+        "parent_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "fee_recipient": "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+        "state_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "receipts_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "logs_bloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+        "prev_randao": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "block_number": "1",
+        "gas_limit": "1",
+        "gas_used": "1",
+        "timestamp": "1",
+        "extra_data": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "base_fee_per_gas": "452312848583266388373324160190187140051835877600158453279131187530910662656",
+        "block_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "transactions_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+        "withdrawals_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"
+      },
+      "value": "652312848583266388373324160190187140051835877600158453279131187530910662656",
+      "pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
+    },
+    "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
+  }
+}`
+
 func TestExecutionHeaderResponseUnmarshal(t *testing.T) {
 	hr := &ExecHeaderResponse{}
 	require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponse), hr))
@@ -186,6 +243,110 @@ func TestExecutionHeaderResponseUnmarshal(t *testing.T) {
 	}
 }

+func TestExecutionHeaderResponseCapellaUnmarshal(t *testing.T) {
+	hr := &ExecHeaderResponseCapella{}
+	require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponseCapella), hr))
+	cases := []struct {
+		expected string
+		actual   string
+		name     string
+	}{
+		{
+			expected: "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505",
+			actual:   hexutil.Encode(hr.Data.Signature),
+			name:     "Signature",
+		},
+		{
+			expected: "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a",
+			actual:   hexutil.Encode(hr.Data.Message.Pubkey),
+			name:     "ExecHeaderResponse.Pubkey",
+		},
+		{
+			expected: "652312848583266388373324160190187140051835877600158453279131187530910662656",
+			actual:   hr.Data.Message.Value.String(),
+			name:     "ExecHeaderResponse.Value",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.ParentHash),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.ParentHash",
+		},
+		{
+			expected: "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+			actual:   hexutil.Encode(hr.Data.Message.Header.FeeRecipient),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.FeeRecipient",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.StateRoot),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.StateRoot",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.ReceiptsRoot),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.ReceiptsRoot",
+		},
+		{
+			expected: "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+			actual:   hexutil.Encode(hr.Data.Message.Header.LogsBloom),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.LogsBloom",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.PrevRandao),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.PrevRandao",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", hr.Data.Message.Header.BlockNumber),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.BlockNumber",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", hr.Data.Message.Header.GasLimit),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.GasLimit",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", hr.Data.Message.Header.GasUsed),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.GasUsed",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", hr.Data.Message.Header.Timestamp),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.Timestamp",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.ExtraData),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.ExtraData",
+		},
+		{
+			expected: "452312848583266388373324160190187140051835877600158453279131187530910662656",
+			actual:   fmt.Sprintf("%d", hr.Data.Message.Header.BaseFeePerGas),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.BaseFeePerGas",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.BlockHash),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.BlockHash",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.TransactionsRoot),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.TransactionsRoot",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(hr.Data.Message.Header.WithdrawalsRoot),
+			name:     "ExecHeaderResponse.ExecutionPayloadHeader.WithdrawalsRoot",
+		},
+	}
+	for _, c := range cases {
+		require.Equal(t, c.expected, c.actual, fmt.Sprintf("unexpected value for field %s", c.name))
+	}
+}
+
 func TestExecutionHeaderResponseToProto(t *testing.T) {
 	bfpg, err := stringToUint256("452312848583266388373324160190187140051835877600158453279131187530910662656")
 	require.NoError(t, err)
@@ -244,6 +405,67 @@ func TestExecutionHeaderResponseToProto(t *testing.T) {
 	require.DeepEqual(t, expected, p)
 }

+func TestExecutionHeaderResponseCapellaToProto(t *testing.T) {
+	bfpg, err := stringToUint256("452312848583266388373324160190187140051835877600158453279131187530910662656")
+	require.NoError(t, err)
+	v, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
+	require.NoError(t, err)
+	hr := &ExecHeaderResponseCapella{}
+	require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponseCapella), hr))
+	p, err := hr.ToProto()
+	require.NoError(t, err)
+	signature, err := hexutil.Decode("0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505")
+	require.NoError(t, err)
+	pubkey, err := hexutil.Decode("0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a")
+	require.NoError(t, err)
+	parentHash, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	feeRecipient, err := hexutil.Decode("0xabcf8e0d4e9587369b2301d0790347320302cc09")
+	require.NoError(t, err)
+	stateRoot, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	receiptsRoot, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	logsBloom, err := hexutil.Decode("0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000")
+	require.NoError(t, err)
+	prevRandao, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	extraData, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	blockHash, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	txRoot, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	withdrawalsRoot, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+
+	expected := &eth.SignedBuilderBidCapella{
+		Message: &eth.BuilderBidCapella{
+			Header: &v1.ExecutionPayloadHeaderCapella{
+				ParentHash:       parentHash,
+				FeeRecipient:     feeRecipient,
+				StateRoot:        stateRoot,
+				ReceiptsRoot:     receiptsRoot,
+				LogsBloom:        logsBloom,
+				PrevRandao:       prevRandao,
+				BlockNumber:      1,
+				GasLimit:         1,
+				GasUsed:          1,
+				Timestamp:        1,
+				ExtraData:        extraData,
+				BaseFeePerGas:    bfpg.SSZBytes(),
+				BlockHash:        blockHash,
+				TransactionsRoot: txRoot,
+				WithdrawalsRoot:  withdrawalsRoot,
+			},
+			Value:  v.SSZBytes(),
+			Pubkey: pubkey,
+		},
+		Signature: signature,
+	}
+	require.DeepEqual(t, expected, p)
+}
+
 var testExampleExecutionPayload = `{
  "version": "bellatrix",
  "data": {
@@ -266,6 +488,36 @@ var testExampleExecutionPayload = `{
  }
 }`

+var testExampleExecutionPayloadCapella = `{
+  "version": "capella",
+  "data": {
+    "parent_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "fee_recipient": "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+    "state_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "receipts_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "logs_bloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+    "prev_randao": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "block_number": "1",
+    "gas_limit": "1",
+    "gas_used": "1",
+    "timestamp": "1",
+    "extra_data": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "base_fee_per_gas": "452312848583266388373324160190187140051835877600158453279131187530910662656",
+    "block_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+    "transactions": [
+      "0x02f878831469668303f51d843b9ac9f9843b9aca0082520894c93269b73096998db66be0441e836d873535cb9c8894a19041886f000080c001a031cc29234036afbf9a1fb9476b463367cb1f957ac0b919b69bbc798436e604aaa018c4e9c3914eb27aadd0b91e10b18655739fcf8c1fc398763a9f1beecb8ddc86"
+    ],
+	"withdrawals": [
+	  {
+		"index": "1",
+		"validator_index": "1",
+		"address": "0xcf8e0d4e9587369b2301d0790347320302cc0943",
+		"amount": "1"
+	  }
+	]
+  }
+}`
+
 func TestExecutionPayloadResponseUnmarshal(t *testing.T) {
 	epr := &ExecPayloadResponse{}
 	require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayload), epr))
@@ -348,6 +600,95 @@ func TestExecutionPayloadResponseUnmarshal(t *testing.T) {
 	require.Equal(t, txHash, hexutil.Encode(epr.Data.Transactions[0]))
 }

+func TestExecutionPayloadResponseCapellaUnmarshal(t *testing.T) {
+	epr := &ExecPayloadResponseCapella{}
+	require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayloadCapella), epr))
+	cases := []struct {
+		expected string
+		actual   string
+		name     string
+	}{
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(epr.Data.ParentHash),
+			name:     "ExecPayloadResponse.ExecutionPayload.ParentHash",
+		},
+		{
+			expected: "0xabcf8e0d4e9587369b2301d0790347320302cc09",
+			actual:   hexutil.Encode(epr.Data.FeeRecipient),
+			name:     "ExecPayloadResponse.ExecutionPayload.FeeRecipient",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(epr.Data.StateRoot),
+			name:     "ExecPayloadResponse.ExecutionPayload.StateRoot",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(epr.Data.ReceiptsRoot),
+			name:     "ExecPayloadResponse.ExecutionPayload.ReceiptsRoot",
+		},
+		{
+			expected: "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
+			actual:   hexutil.Encode(epr.Data.LogsBloom),
+			name:     "ExecPayloadResponse.ExecutionPayload.LogsBloom",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(epr.Data.PrevRandao),
+			name:     "ExecPayloadResponse.ExecutionPayload.PrevRandao",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", epr.Data.BlockNumber),
+			name:     "ExecPayloadResponse.ExecutionPayload.BlockNumber",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", epr.Data.GasLimit),
+			name:     "ExecPayloadResponse.ExecutionPayload.GasLimit",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", epr.Data.GasUsed),
+			name:     "ExecPayloadResponse.ExecutionPayload.GasUsed",
+		},
+		{
+			expected: "1",
+			actual:   fmt.Sprintf("%d", epr.Data.Timestamp),
+			name:     "ExecPayloadResponse.ExecutionPayload.Timestamp",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(epr.Data.ExtraData),
+			name:     "ExecPayloadResponse.ExecutionPayload.ExtraData",
+		},
+		{
+			expected: "452312848583266388373324160190187140051835877600158453279131187530910662656",
+			actual:   fmt.Sprintf("%d", epr.Data.BaseFeePerGas),
+			name:     "ExecPayloadResponse.ExecutionPayload.BaseFeePerGas",
+		},
+		{
+			expected: "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
+			actual:   hexutil.Encode(epr.Data.BlockHash),
+			name:     "ExecPayloadResponse.ExecutionPayload.BlockHash",
+		},
+	}
+	for _, c := range cases {
+		require.Equal(t, c.expected, c.actual, fmt.Sprintf("unexpected value for field %s", c.name))
+	}
+	require.Equal(t, 1, len(epr.Data.Transactions))
+	txHash := "0x02f878831469668303f51d843b9ac9f9843b9aca0082520894c93269b73096998db66be0441e836d873535cb9c8894a19041886f000080c001a031cc29234036afbf9a1fb9476b463367cb1f957ac0b919b69bbc798436e604aaa018c4e9c3914eb27aadd0b91e10b18655739fcf8c1fc398763a9f1beecb8ddc86"
+	require.Equal(t, txHash, hexutil.Encode(epr.Data.Transactions[0]))
+
+	require.Equal(t, 1, len(epr.Data.Withdrawals))
+	w := epr.Data.Withdrawals[0]
+	assert.Equal(t, uint64(1), w.Index.Uint64())
+	assert.Equal(t, uint64(1), w.ValidatorIndex.Uint64())
+	assert.DeepEqual(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943", w.Address.String())
+	assert.Equal(t, uint64(1), w.Amount.Uint64())
+}
+
 func TestExecutionPayloadResponseToProto(t *testing.T) {
 	hr := &ExecPayloadResponse{}
 	require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayload), hr))
@@ -396,6 +737,65 @@ func TestExecutionPayloadResponseToProto(t *testing.T) {
 	require.DeepEqual(t, expected, p)
 }

+func TestExecutionPayloadResponseCapellaToProto(t *testing.T) {
+	hr := &ExecPayloadResponseCapella{}
+	require.NoError(t, json.Unmarshal([]byte(testExampleExecutionPayloadCapella), hr))
+	p, err := hr.ToProto()
+	require.NoError(t, err)
+
+	parentHash, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	feeRecipient, err := hexutil.Decode("0xabcf8e0d4e9587369b2301d0790347320302cc09")
+	require.NoError(t, err)
+	stateRoot, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	receiptsRoot, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	logsBloom, err := hexutil.Decode("0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000")
+	require.NoError(t, err)
+	prevRandao, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	extraData, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+	blockHash, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2")
+	require.NoError(t, err)
+
+	tx, err := hexutil.Decode("0x02f878831469668303f51d843b9ac9f9843b9aca0082520894c93269b73096998db66be0441e836d873535cb9c8894a19041886f000080c001a031cc29234036afbf9a1fb9476b463367cb1f957ac0b919b69bbc798436e604aaa018c4e9c3914eb27aadd0b91e10b18655739fcf8c1fc398763a9f1beecb8ddc86")
+	require.NoError(t, err)
+	txList := [][]byte{tx}
+	address, err := hexutil.Decode("0xcf8e0d4e9587369b2301d0790347320302cc0943")
+	require.NoError(t, err)
+
+	bfpg, err := stringToUint256("452312848583266388373324160190187140051835877600158453279131187530910662656")
+	require.NoError(t, err)
+	expected := &v1.ExecutionPayloadCapella{
+		ParentHash:    parentHash,
+		FeeRecipient:  feeRecipient,
+		StateRoot:     stateRoot,
+		ReceiptsRoot:  receiptsRoot,
+		LogsBloom:     logsBloom,
+		PrevRandao:    prevRandao,
+		BlockNumber:   1,
+		GasLimit:      1,
+		GasUsed:       1,
+		Timestamp:     1,
+		ExtraData:     extraData,
+		BaseFeePerGas: bfpg.SSZBytes(),
+		BlockHash:     blockHash,
+		Transactions:  txList,
+		Withdrawals: []*v1.Withdrawal{
+			{
+				Index:          1,
+				ValidatorIndex: 1,
+				Address:        address,
+				Amount:         1,
+			},
+		},
+	}
+	require.DeepEqual(t, expected, p)
+
+}
+
 func pbEth1Data() *eth.Eth1Data {
 	return &eth.Eth1Data{
 		DepositRoot:  make([]byte, 32),
@@ -604,6 +1004,28 @@ func pbExecutionPayloadHeader(t *testing.T) *v1.ExecutionPayloadHeader {
 	}
 }

+func pbExecutionPayloadHeaderCapella(t *testing.T) *v1.ExecutionPayloadHeaderCapella {
+	bfpg, err := stringToUint256("452312848583266388373324160190187140051835877600158453279131187530910662656")
+	require.NoError(t, err)
+	return &v1.ExecutionPayloadHeaderCapella{
+		ParentHash:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		FeeRecipient:     ezDecode(t, "0xabcf8e0d4e9587369b2301d0790347320302cc09"),
+		StateRoot:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		ReceiptsRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		LogsBloom:        ezDecode(t, "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
+		PrevRandao:       ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		BlockNumber:      1,
+		GasLimit:         1,
+		GasUsed:          1,
+		Timestamp:        1,
+		ExtraData:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		BaseFeePerGas:    bfpg.SSZBytes(),
+		BlockHash:        ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		TransactionsRoot: ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		WithdrawalsRoot:  ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+	}
+}
+
 func TestExecutionPayloadHeader_MarshalJSON(t *testing.T) {
 	h := &ExecutionPayloadHeader{
 		ExecutionPayloadHeader: pbExecutionPayloadHeader(t),
@@ -614,6 +1036,16 @@ func TestExecutionPayloadHeader_MarshalJSON(t *testing.T) {
 	require.Equal(t, expected, string(b))
 }

+func TestExecutionPayloadHeaderCapella_MarshalJSON(t *testing.T) {
+	h := &ExecutionPayloadHeaderCapella{
+		ExecutionPayloadHeaderCapella: pbExecutionPayloadHeaderCapella(t),
+	}
+	b, err := json.Marshal(h)
+	require.NoError(t, err)
+	expected := `{"parent_hash":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","fee_recipient":"0xabcf8e0d4e9587369b2301d0790347320302cc09","state_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","receipts_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","logs_bloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","prev_randao":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","block_number":"1","gas_limit":"1","gas_used":"1","timestamp":"1","extra_data":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","base_fee_per_gas":"452312848583266388373324160190187140051835877600158453279131187530910662656","block_hash":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","transactions_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2","withdrawals_root":"0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"}`
+	require.Equal(t, expected, string(b))
+}
+
 var testBuilderBid = `{
    "version":"bellatrix",
 	"data":{
@@ -783,6 +1215,35 @@ func TestMarshalBlindedBeaconBlockBodyBellatrix(t *testing.T) {
 	require.Equal(t, string(expected[0:len(expected)-1]), string(m))
 }

+func TestMarshalBlindedBeaconBlockBodyCapella(t *testing.T) {
+	expected, err := os.ReadFile("testdata/blinded-block-capella.json")
+	require.NoError(t, err)
+	b := &BlindedBeaconBlockCapella{BlindedBeaconBlockCapella: &eth.BlindedBeaconBlockCapella{
+		Slot:          1,
+		ProposerIndex: 1,
+		ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		StateRoot:     ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
+		Body: &eth.BlindedBeaconBlockBodyCapella{
+			RandaoReveal:           ezDecode(t, "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"),
+			Eth1Data:               pbEth1Data(),
+			Graffiti:               ezDecode(t, "0xdeadbeefc0ffee"),
+			ProposerSlashings:      []*eth.ProposerSlashing{pbProposerSlashing(t)},
+			AttesterSlashings:      []*eth.AttesterSlashing{pbAttesterSlashing(t)},
+			Attestations:           []*eth.Attestation{pbAttestation(t)},
+			Deposits:               []*eth.Deposit{pbDeposit(t)},
+			VoluntaryExits:         []*eth.SignedVoluntaryExit{pbSignedVoluntaryExit(t)},
+			SyncAggregate:          pbSyncAggregate(),
+			ExecutionPayloadHeader: pbExecutionPayloadHeaderCapella(t),
+		},
+	}}
+	m, err := json.Marshal(b)
+	require.NoError(t, err)
+	// string error output is easier to deal with
+	// -1 end slice index on expected is to get rid of trailing newline
+	// if you update this fixture and this test breaks, you probably removed the trailing newline
+	require.Equal(t, string(expected[0:len(expected)-1]), string(m))
+}
+
 func TestRoundTripUint256(t *testing.T) {
 	vs := "4523128485832663883733241601901871400518358776001584532791311875309106626"
 	u, err := stringToUint256(vs)
@@ -818,6 +1279,16 @@ func TestExecutionPayloadHeaderRoundtrip(t *testing.T) {
 	require.DeepEqual(t, string(expected[0:len(expected)-1]), string(m))
 }

+func TestExecutionPayloadHeaderCapellaRoundtrip(t *testing.T) {
+	expected, err := os.ReadFile("testdata/execution-payload-capella.json")
+	require.NoError(t, err)
+	hu := &ExecutionPayloadHeaderCapella{}
+	require.NoError(t, json.Unmarshal(expected, hu))
+	m, err := json.Marshal(hu)
+	require.NoError(t, err)
+	require.DeepEqual(t, string(expected[0:len(expected)-1]), string(m))
+}
+
 func TestErrorMessage_non200Err(t *testing.T) {
 	mockRequest := &http.Request{
 		URL: &url.URL{Path: "example.com"},
@@ -904,5 +1375,4 @@ func TestErrorMessage_non200Err(t *testing.T) {
 			}
 		})
 	}
-
 }
--- a/async/multilock.go
+++ b/async/multilock.go
@@ -3,7 +3,9 @@ Copyright 2017 Albert Tedja
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
-    http://www.apache.org/licenses/LICENSE-2.0
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
--- a/async/multilock_test.go
+++ b/async/multilock_test.go
@@ -3,7 +3,9 @@ Copyright 2017 Albert Tedja
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
-    http://www.apache.org/licenses/LICENSE-2.0
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
--- a/beacon-chain/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -6,6 +6,7 @@ go_library(
        "chain_info.go",
        "error.go",
        "execution_engine.go",
+        "forkchoice_update_execution.go",
        "head.go",
        "head_sync_committee_info.go",
        "init_sync_process_block.go",
@@ -21,7 +22,6 @@ go_library(
        "receive_attestation.go",
        "receive_block.go",
        "service.go",
-        "state_balance_cache.go",
        "weak_subjectivity_checks.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/v3/beacon-chain/blockchain",
@@ -53,6 +53,7 @@ go_library(
        "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
        "//beacon-chain/forkchoice/types:go_default_library",
        "//beacon-chain/operations/attestations:go_default_library",
+        "//beacon-chain/operations/blstoexec:go_default_library",
        "//beacon-chain/operations/slashings:go_default_library",
        "//beacon-chain/operations/voluntaryexits:go_default_library",
        "//beacon-chain/p2p:go_default_library",
@@ -63,6 +64,7 @@ go_library(
        "//config/params:go_default_library",
        "//consensus-types/blocks:go_default_library",
        "//consensus-types/interfaces:go_default_library",
+        "//consensus-types/payload-attribute:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//crypto/bls:go_default_library",
        "//encoding/bytesutil:go_default_library",
@@ -102,6 +104,7 @@ go_test(
        "chain_info_test.go",
        "checktags_test.go",
        "execution_engine_test.go",
+        "forkchoice_update_execution_test.go",
        "head_sync_committee_info_test.go",
        "head_test.go",
        "init_test.go",
--- a/beacon-chain/blockchain/chain_info.go
+++ b/beacon-chain/blockchain/chain_info.go
@@ -13,7 +13,7 @@ import (
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
@@ -33,13 +33,13 @@ type ChainInfoFetcher interface {
 // HeadUpdater defines a common interface for methods in blockchain service
 // which allow to update the head info
 type HeadUpdater interface {
-	UpdateHead(context.Context) error
+	UpdateHead(context.Context, primitives.Slot)
 }

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

 // GenesisFetcher retrieves the Ethereum consensus data related to its genesis.
@@ -50,16 +50,17 @@ type GenesisFetcher interface {
 // HeadFetcher defines a common interface for methods in blockchain service which
 // directly retrieve head related data.
 type HeadFetcher interface {
-	HeadSlot() types.Slot
+	HeadSlot() primitives.Slot
 	HeadRoot(ctx context.Context) ([]byte, error)
-	HeadBlock(ctx context.Context) (interfaces.SignedBeaconBlock, error)
+	HeadBlock(ctx context.Context) (interfaces.ReadOnlySignedBeaconBlock, error)
 	HeadState(ctx context.Context) (state.BeaconState, error)
-	HeadValidatorsIndices(ctx context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error)
+	HeadStateReadOnly(ctx context.Context) (state.ReadOnlyBeaconState, error)
+	HeadValidatorsIndices(ctx context.Context, epoch primitives.Epoch) ([]primitives.ValidatorIndex, error)
 	HeadGenesisValidatorsRoot() [32]byte
 	HeadETH1Data() *ethpb.Eth1Data
-	HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool)
-	HeadValidatorIndexToPublicKey(ctx context.Context, index types.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error)
-	ChainHeads() ([][32]byte, []types.Slot)
+	HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLength]byte) (primitives.ValidatorIndex, bool)
+	HeadValidatorIndexToPublicKey(ctx context.Context, index primitives.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error)
+	ChainHeads() ([][32]byte, []primitives.Slot)
 	HeadSyncCommitteeFetcher
 	HeadDomainFetcher
 }
@@ -83,7 +84,7 @@ type FinalizationFetcher interface {
 	FinalizedCheckpt() *ethpb.Checkpoint
 	CurrentJustifiedCheckpt() *ethpb.Checkpoint
 	PreviousJustifiedCheckpt() *ethpb.Checkpoint
-	VerifyFinalizedBlkDescendant(ctx context.Context, blockRoot [32]byte) error
+	InForkchoice([32]byte) bool
 	IsFinalized(ctx context.Context, blockRoot [32]byte) bool
 }

@@ -95,30 +96,38 @@ type OptimisticModeFetcher interface {

 // FinalizedCheckpt returns the latest finalized checkpoint from chain store.
 func (s *Service) FinalizedCheckpt() *ethpb.Checkpoint {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	cp := s.ForkChoicer().FinalizedCheckpoint()
 	return &ethpb.Checkpoint{Epoch: cp.Epoch, Root: bytesutil.SafeCopyBytes(cp.Root[:])}
 }

 // PreviousJustifiedCheckpt returns the current justified checkpoint from chain store.
 func (s *Service) PreviousJustifiedCheckpt() *ethpb.Checkpoint {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	cp := s.ForkChoicer().PreviousJustifiedCheckpoint()
 	return &ethpb.Checkpoint{Epoch: cp.Epoch, Root: bytesutil.SafeCopyBytes(cp.Root[:])}
 }

 // CurrentJustifiedCheckpt returns the current justified checkpoint from chain store.
 func (s *Service) CurrentJustifiedCheckpt() *ethpb.Checkpoint {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	cp := s.ForkChoicer().JustifiedCheckpoint()
 	return &ethpb.Checkpoint{Epoch: cp.Epoch, Root: bytesutil.SafeCopyBytes(cp.Root[:])}
 }

 // BestJustifiedCheckpt returns the best justified checkpoint from store.
 func (s *Service) BestJustifiedCheckpt() *ethpb.Checkpoint {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	cp := s.ForkChoicer().BestJustifiedCheckpoint()
 	return &ethpb.Checkpoint{Epoch: cp.Epoch, Root: bytesutil.SafeCopyBytes(cp.Root[:])}
 }

 // HeadSlot returns the slot of the head of the chain.
-func (s *Service) HeadSlot() types.Slot {
+func (s *Service) HeadSlot() primitives.Slot {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()

@@ -157,7 +166,7 @@ func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
 // HeadBlock returns the head block of the chain.
 // If the head is nil from service struct,
 // it will attempt to get the head block from DB.
-func (s *Service) HeadBlock(ctx context.Context) (interfaces.SignedBeaconBlock, error) {
+func (s *Service) HeadBlock(ctx context.Context) (interfaces.ReadOnlySignedBeaconBlock, error) {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()

@@ -187,13 +196,35 @@ func (s *Service) HeadState(ctx context.Context) (state.BeaconState, error) {
 	return s.cfg.StateGen.StateByRoot(ctx, s.headRoot())
 }

+// HeadStateReadOnly returns the read only head state of the chain.
+// If the head is nil from service struct, it will attempt to get the
+// head state from DB. Any callers of this method MUST only use the
+// state instance to read fields from the state. Any type assertions back
+// to the concrete type and subsequent use of it could lead to corruption
+// of the state.
+func (s *Service) HeadStateReadOnly(ctx context.Context) (state.ReadOnlyBeaconState, error) {
+	ctx, span := trace.StartSpan(ctx, "blockChain.HeadStateReadOnly")
+	defer span.End()
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	ok := s.hasHeadState()
+	span.AddAttributes(trace.BoolAttribute("cache_hit", ok))
+
+	if ok {
+		return s.headStateReadOnly(ctx), nil
+	}
+
+	return s.cfg.StateGen.StateByRoot(ctx, s.headRoot())
+}
+
 // HeadValidatorsIndices returns a list of active validator indices from the head view of a given epoch.
-func (s *Service) HeadValidatorsIndices(ctx context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error) {
+func (s *Service) HeadValidatorsIndices(ctx context.Context, epoch primitives.Epoch) ([]primitives.ValidatorIndex, error) {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()

 	if !s.hasHeadState() {
-		return []types.ValidatorIndex{}, nil
+		return []primitives.ValidatorIndex{}, nil
 	}
 	return helpers.ActiveValidatorIndices(ctx, s.headState(ctx), epoch)
 }
@@ -254,6 +285,8 @@ func (s *Service) CurrentFork() *ethpb.Fork {

 // IsCanonical returns true if the input block root is part of the canonical chain.
 func (s *Service) IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error) {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	// If the block has not been finalized, check fork choice store to see if the block is canonical
 	if s.cfg.ForkChoiceStore.HasNode(blockRoot) {
 		return s.cfg.ForkChoiceStore.IsCanonical(blockRoot), nil
@@ -265,12 +298,14 @@ func (s *Service) IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, er

 // ChainHeads returns all possible chain heads (leaves of fork choice tree).
 // Heads roots and heads slots are returned.
-func (s *Service) ChainHeads() ([][32]byte, []types.Slot) {
+func (s *Service) ChainHeads() ([][32]byte, []primitives.Slot) {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	return s.cfg.ForkChoiceStore.Tips()
 }

 // HeadPublicKeyToValidatorIndex returns the validator index of the `pubkey` in current head state.
-func (s *Service) HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool) {
+func (s *Service) HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLength]byte) (primitives.ValidatorIndex, bool) {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()
 	if !s.hasHeadState() {
@@ -280,7 +315,7 @@ func (s *Service) HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLen
 }

 // HeadValidatorIndexToPublicKey returns the pubkey of the validator `index`  in current head state.
-func (s *Service) HeadValidatorIndexToPublicKey(_ context.Context, index types.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error) {
+func (s *Service) HeadValidatorIndexToPublicKey(_ context.Context, index primitives.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error) {
 	s.headLock.RLock()
 	defer s.headLock.RUnlock()
 	if !s.hasHeadState() {
@@ -307,9 +342,8 @@ func (s *Service) IsOptimistic(ctx context.Context) (bool, error) {
 	headRoot := s.head.root
 	s.headLock.RUnlock()

-	if s.cfg.ForkChoiceStore.AllTipsAreInvalid() {
-		return true, nil
-	}
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	optimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(headRoot)
 	if err == nil {
 		return optimistic, nil
@@ -325,16 +359,34 @@ func (s *Service) IsOptimistic(ctx context.Context) (bool, error) {
 // IsFinalized returns true if the input root is finalized.
 // It first checks latest finalized root then checks finalized root index in DB.
 func (s *Service) IsFinalized(ctx context.Context, root [32]byte) bool {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
 	if s.ForkChoicer().FinalizedCheckpoint().Root == root {
 		return true
 	}
+	// If node exists in our store, then it is not
+	// finalized.
+	if s.ForkChoicer().HasNode(root) {
+		return false
+	}
 	return s.cfg.BeaconDB.IsFinalizedBlock(ctx, root)
 }

+// InForkchoice returns true if the given root is found in forkchoice
+// This in particular means that the blockroot is a descendant of the
+// finalized checkpoint
+func (s *Service) InForkchoice(root [32]byte) bool {
+	s.ForkChoicer().RLock()
+	defer s.ForkChoicer().RUnlock()
+	return s.ForkChoicer().HasNode(root)
+}
+
 // IsOptimisticForRoot takes the root as argument instead of the current head
 // and returns true if it is optimistic.
 func (s *Service) IsOptimisticForRoot(ctx context.Context, root [32]byte) (bool, error) {
+	s.ForkChoicer().RLock()
 	optimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(root)
+	s.ForkChoicer().RUnlock()
 	if err == nil {
 		return optimistic, nil
 	}
--- a/beacon-chain/blockchain/chain_info_norace_test.go
+++ b/beacon-chain/blockchain/chain_info_norace_test.go
@@ -8,6 +8,7 @@ import (
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 	"github.com/prysmaticlabs/prysm/v3/testing/util"
@@ -81,6 +82,9 @@ func TestHeadState_DataRace(t *testing.T) {
 	require.NoError(t, err)
 	wait := make(chan struct{})
 	st, _ := util.DeterministicGenesisState(t, 1)
+	root := bytesutil.ToBytes32(bytesutil.PadTo([]byte{'s'}, 32))
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(context.Background(), root))
+	require.NoError(t, beaconDB.SaveState(context.Background(), st, root))
 	go func() {
 		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}, b, st))
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -14,7 +14,7 @@ import (
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	enginev1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
@@ -33,7 +33,7 @@ var _ ForkFetcher = (*Service)(nil)
 // insert into forkchoice
 func prepareForkchoiceState(
 	_ context.Context,
-	slot types.Slot,
+	slot primitives.Slot,
 	blockRoot [32]byte,
 	parentRoot [32]byte,
 	payloadHash [32]byte,
@@ -74,7 +74,7 @@ func TestHeadRoot_Nil(t *testing.T) {
 func TestService_ForkChoiceStore(t *testing.T) {
 	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New()}}
 	p := c.ForkChoiceStore()
-	require.Equal(t, types.Epoch(0), p.FinalizedCheckpoint().Epoch)
+	require.Equal(t, primitives.Epoch(0), p.FinalizedCheckpoint().Epoch)
 }

 func TestFinalizedCheckpt_GenesisRootOk(t *testing.T) {
@@ -96,7 +96,7 @@ func TestFinalizedCheckpt_GenesisRootOk(t *testing.T) {
 	cp = service.CurrentJustifiedCheckpt()
 	assert.DeepEqual(t, [32]byte{}, bytesutil.ToBytes32(cp.Root))
 	// check that forkchoice has the right genesis root as the node root
-	root, err := fcs.Head(ctx, []uint64{})
+	root, err := fcs.Head(ctx)
 	require.NoError(t, err)
 	require.Equal(t, service.originBlockRoot, root)

@@ -114,8 +114,12 @@ func TestCurrentJustifiedCheckpt_CanRetrieve(t *testing.T) {
 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)

-	cp := &forkchoicetypes.Checkpoint{Epoch: 6, Root: [32]byte{'j'}}
-	require.NoError(t, fcs.UpdateJustifiedCheckpoint(cp))
+	jroot := [32]byte{'j'}
+	cp := &forkchoicetypes.Checkpoint{Epoch: 6, Root: jroot}
+	bState, _ := util.DeterministicGenesisState(t, 10)
+	require.NoError(t, beaconDB.SaveState(ctx, bState, jroot))
+
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, cp))
 	jp := service.CurrentJustifiedCheckpt()
 	assert.Equal(t, cp.Epoch, jp.Epoch, "Unexpected justified epoch")
 	require.Equal(t, cp.Root, bytesutil.ToBytes32(jp.Root))
@@ -125,8 +129,11 @@ func TestHeadSlot_CanRetrieve(t *testing.T) {
 	c := &Service{}
 	s, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{})
 	require.NoError(t, err)
-	c.head = &head{slot: 100, state: s}
-	assert.Equal(t, types.Slot(100), c.HeadSlot())
+	b, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlock())
+	require.NoError(t, err)
+	b.SetSlot(100)
+	c.head = &head{block: b, state: s}
+	assert.Equal(t, primitives.Slot(100), c.HeadSlot())
 }

 func TestHeadRoot_CanRetrieve(t *testing.T) {
@@ -328,7 +335,7 @@ func TestService_ChainHeads(t *testing.T) {
 	st, blkRoot, err = prepareForkchoiceState(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, params.BeaconConfig().ZeroHash, ojc, ofc)
 	require.NoError(t, err)
 	require.NoError(t, c.cfg.ForkChoiceStore.InsertNode(ctx, st, blkRoot))
-	st, blkRoot, err = prepareForkchoiceState(ctx, 103, [32]byte{'d'}, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
+	st, blkRoot, err = prepareForkchoiceState(ctx, 103, [32]byte{'d'}, [32]byte{'a'}, params.BeaconConfig().ZeroHash, ojc, ofc)
 	require.NoError(t, err)
 	require.NoError(t, c.cfg.ForkChoiceStore.InsertNode(ctx, st, blkRoot))
 	st, blkRoot, err = prepareForkchoiceState(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, params.BeaconConfig().ZeroHash, ojc, ofc)
@@ -337,7 +344,7 @@ func TestService_ChainHeads(t *testing.T) {

 	roots, slots := c.ChainHeads()
 	require.Equal(t, 3, len(roots))
-	rootMap := map[[32]byte]types.Slot{{'c'}: 102, {'d'}: 103, {'e'}: 104}
+	rootMap := map[[32]byte]primitives.Slot{{'c'}: 102, {'d'}: 103, {'e'}: 104}
 	for i, root := range roots {
 		slot, ok := rootMap[root]
 		require.Equal(t, true, ok)
@@ -358,7 +365,7 @@ func TestService_HeadPublicKeyToValidatorIndex(t *testing.T) {

 	i, e := c.HeadPublicKeyToValidatorIndex(bytesutil.ToBytes48(v.PublicKey))
 	require.Equal(t, true, e)
-	require.Equal(t, types.ValidatorIndex(0), i)
+	require.Equal(t, primitives.ValidatorIndex(0), i)
 }

 func TestService_HeadPublicKeyToValidatorIndexNil(t *testing.T) {
@@ -367,12 +374,12 @@ func TestService_HeadPublicKeyToValidatorIndexNil(t *testing.T) {

 	idx, e := c.HeadPublicKeyToValidatorIndex([fieldparams.BLSPubkeyLength]byte{})
 	require.Equal(t, false, e)
-	require.Equal(t, types.ValidatorIndex(0), idx)
+	require.Equal(t, primitives.ValidatorIndex(0), idx)

 	c.head = &head{state: nil}
 	i, e := c.HeadPublicKeyToValidatorIndex([fieldparams.BLSPubkeyLength]byte{})
 	require.Equal(t, false, e)
-	require.Equal(t, types.ValidatorIndex(0), i)
+	require.Equal(t, primitives.ValidatorIndex(0), i)
 }

 func TestService_HeadValidatorIndexToPublicKey(t *testing.T) {
@@ -412,7 +419,7 @@ func TestService_IsOptimistic(t *testing.T) {
 	ctx := context.Background()
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
-	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New()}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New()}, head: &head{root: [32]byte{'b'}}}
 	st, blkRoot, err := prepareForkchoiceState(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
 	require.NoError(t, err)
 	require.NoError(t, c.cfg.ForkChoiceStore.InsertNode(ctx, st, blkRoot))
@@ -435,7 +442,7 @@ func TestService_IsOptimisticBeforeBellatrix(t *testing.T) {

 func TestService_IsOptimisticForRoot(t *testing.T) {
 	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New()}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New()}, head: &head{root: [32]byte{'b'}}}
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	st, blkRoot, err := prepareForkchoiceState(ctx, 100, [32]byte{'a'}, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
@@ -453,7 +460,7 @@ func TestService_IsOptimisticForRoot(t *testing.T) {
 func TestService_IsOptimisticForRoot_DB(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()
-	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: doublylinkedtree.New()}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: doublylinkedtree.New()}, head: &head{root: [32]byte{'b'}}}
 	c.head = &head{root: params.BeaconConfig().ZeroHash}
 	b := util.NewBeaconBlock()
 	b.Block.Slot = 10
@@ -511,7 +518,7 @@ func TestService_IsOptimisticForRoot_DB(t *testing.T) {
 func TestService_IsOptimisticForRoot_DB_non_canonical(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()
-	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: doublylinkedtree.New()}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: doublylinkedtree.New()}, head: &head{root: [32]byte{'b'}}}
 	c.head = &head{root: params.BeaconConfig().ZeroHash}
 	b := util.NewBeaconBlock()
 	b.Block.Slot = 10
--- a/beacon-chain/blockchain/error.go
+++ b/beacon-chain/blockchain/error.go
@@ -8,7 +8,7 @@ var (
 	// ErrInvalidBlockHashPayloadStatus is returned when the payload has invalid block hash.
 	ErrInvalidBlockHashPayloadStatus = invalidBlock{error: errors.New("received an INVALID_BLOCK_HASH payload from execution engine")}
 	// ErrUndefinedExecutionEngineError is returned when the execution engine returns an error that is not defined
-	ErrUndefinedExecutionEngineError = errors.New("received an undefined ee error")
+	ErrUndefinedExecutionEngineError = errors.New("received an undefined execution engine error")
 	// errNilFinalizedInStore is returned when a nil finalized checkpt is returned from store.
 	errNilFinalizedInStore = errors.New("nil finalized checkpoint returned from store")
 	// errNilFinalizedCheckpoint is returned when a nil finalized checkpt is returned from a state.
@@ -19,18 +19,14 @@ var (
 	errInvalidNilSummary = errors.New("nil summary returned from the DB")
 	// errWrongBlockCount is returned when the wrong number of blocks or block roots is used
 	errWrongBlockCount = errors.New("wrong number of blocks or block roots")
-	// block is not a valid optimistic candidate block
-	errNotOptimisticCandidate = errors.New("block is not suitable for optimistic sync")
 	// errBlockNotFoundInCacheOrDB is returned when a block is not found in the cache or DB.
 	errBlockNotFoundInCacheOrDB = errors.New("block not found in cache or db")
-	// errNilStateFromStategen is returned when a nil state is returned from the state generator.
-	errNilStateFromStategen = errors.New("justified state can't be nil")
 	// errWSBlockNotFound is returned when a block is not found in the WS cache or DB.
 	errWSBlockNotFound = errors.New("weak subjectivity root not found in db")
 	// errWSBlockNotFoundInEpoch is returned when a block is not found in the WS cache or DB within epoch.
 	errWSBlockNotFoundInEpoch = errors.New("weak subjectivity root not found in db within epoch")
 	// errNotDescendantOfFinalized is returned when a block is not a descendant of the finalized checkpoint
-	errNotDescendantOfFinalized = invalidBlock{error: errors.New("not descendant of finalized checkpoint")}
+	ErrNotDescendantOfFinalized = invalidBlock{error: errors.New("not descendant of finalized checkpoint")}
 )

 // An invalid block is the block that fails state transition based on the core protocol rules.
--- a/beacon-chain/blockchain/execution_engine.go
+++ b/beacon-chain/blockchain/execution_engine.go
@@ -15,9 +15,11 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	payloadattribute "github.com/prysmaticlabs/prysm/v3/consensus-types/payload-attribute"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	enginev1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
+	"github.com/prysmaticlabs/prysm/v3/runtime/version"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
@@ -29,7 +31,7 @@ var defaultLatestValidHash = bytesutil.PadTo([]byte{0xff}, 32)
 type notifyForkchoiceUpdateArg struct {
 	headState state.BeaconState
 	headRoot  [32]byte
-	headBlock interfaces.BeaconBlock
+	headBlock interfaces.ReadOnlyBeaconBlock
 }

 // notifyForkchoiceUpdate signals execution engine the fork choice updates. Execution engine should:
@@ -67,11 +69,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *notifyForkcho
 	}

 	nextSlot := s.CurrentSlot() + 1 // Cache payload ID for next slot proposer.
-	hasAttr, attr, proposerId, err := s.getPayloadAttribute(ctx, arg.headState, nextSlot)
-	if err != nil {
-		log.WithError(err).Error("Could not get head payload attribute")
-		return nil, nil
-	}
+	hasAttr, attr, proposerId := s.getPayloadAttribute(ctx, arg.headState, nextSlot)

 	payloadID, lastValidHash, err := s.cfg.ExecutionEngineCaller.ForkchoiceUpdated(ctx, fcs, attr)
 	if err != nil {
@@ -100,7 +98,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *notifyForkcho
 				return nil, nil
 			}

-			r, err := s.cfg.ForkChoiceStore.Head(ctx, s.justifiedBalances.balances)
+			r, err := s.cfg.ForkChoiceStore.Head(ctx)
 			if err != nil {
 				log.WithFields(logrus.Fields{
 					"slot":                 headBlk.Slot(),
@@ -150,7 +148,8 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *notifyForkcho
 		log.WithError(err).Error("Could not set head root to valid")
 		return nil, nil
 	}
-	if hasAttr && payloadID != nil { // If the forkchoice update call has an attribute, update the proposer payload ID cache.
+	// If the forkchoice update call has an attribute, update the proposer payload ID cache.
+	if hasAttr && payloadID != nil {
 		var pId [8]byte
 		copy(pId[:], payloadID[:])
 		s.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(nextSlot, proposerId, pId, arg.headRoot)
@@ -183,7 +182,7 @@ 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.SignedBeaconBlock) (bool, error) {
+	postStateHeader interfaces.ExecutionData, blk interfaces.ReadOnlySignedBeaconBlock) (bool, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.notifyNewPayload")
 	defer span.End()

@@ -251,22 +250,25 @@ func (s *Service) notifyNewPayload(ctx context.Context, postStateVersion int,

 // 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 types.Slot) (bool, *enginev1.PayloadAttributes, types.ValidatorIndex, error) {
+func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState, slot primitives.Slot) (bool, payloadattribute.Attributer, primitives.ValidatorIndex) {
+	emptyAttri := payloadattribute.EmptyWithVersion(st.Version())
 	// Root is `[32]byte{}` since we are retrieving proposer ID of a given slot. During insertion at assignment the root was not known.
 	proposerID, _, ok := s.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(slot, [32]byte{} /* root */)
 	if !ok { // There's no need to build attribute if there is no proposer for slot.
-		return false, nil, 0, nil
+		return false, emptyAttri, 0
 	}

 	// Get previous randao.
 	st = st.Copy()
 	st, err := transition.ProcessSlotsIfPossible(ctx, st, slot)
 	if err != nil {
-		return false, nil, 0, err
+		log.WithError(err).Error("Could not process slots to get payload attribute")
+		return false, emptyAttri, 0
 	}
 	prevRando, err := helpers.RandaoMix(st, time.CurrentEpoch(st))
 	if err != nil {
-		return false, nil, 0, nil
+		log.WithError(err).Error("Could not get randao mix to get payload attribute")
+		return false, emptyAttri, 0
 	}

 	// Get fee recipient.
@@ -284,7 +286,8 @@ func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState,
 				"Please refer to our documentation for instructions")
 		}
 	case err != nil:
-		return false, nil, 0, errors.Wrap(err, "could not get fee recipient in db")
+		log.WithError(err).Error("Could not get fee recipient to get payload attribute")
+		return false, emptyAttri, 0
 	default:
 		feeRecipient = recipient
 	}
@@ -292,14 +295,44 @@ func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState,
 	// Get timestamp.
 	t, err := slots.ToTime(uint64(s.genesisTime.Unix()), slot)
 	if err != nil {
-		return false, nil, 0, err
+		log.WithError(err).Error("Could not get timestamp to get payload attribute")
+		return false, emptyAttri, 0
 	}
-	attr := &enginev1.PayloadAttributes{
-		Timestamp:             uint64(t.Unix()),
-		PrevRandao:            prevRando,
-		SuggestedFeeRecipient: feeRecipient.Bytes(),
+
+	var attr payloadattribute.Attributer
+	switch st.Version() {
+	case version.Capella:
+		withdrawals, err := st.ExpectedWithdrawals()
+		if err != nil {
+			log.WithError(err).Error("Could not get expected withdrawals to get payload attribute")
+			return false, emptyAttri, 0
+		}
+		attr, err = payloadattribute.New(&enginev1.PayloadAttributesV2{
+			Timestamp:             uint64(t.Unix()),
+			PrevRandao:            prevRando,
+			SuggestedFeeRecipient: feeRecipient.Bytes(),
+			Withdrawals:           withdrawals,
+		})
+		if err != nil {
+			log.WithError(err).Error("Could not get payload attribute")
+			return false, emptyAttri, 0
+		}
+	case version.Bellatrix:
+		attr, err = payloadattribute.New(&enginev1.PayloadAttributes{
+			Timestamp:             uint64(t.Unix()),
+			PrevRandao:            prevRando,
+			SuggestedFeeRecipient: feeRecipient.Bytes(),
+		})
+		if err != nil {
+			log.WithError(err).Error("Could not get payload attribute")
+			return false, emptyAttri, 0
+		}
+	default:
+		log.WithField("version", st.Version()).Error("Could not get payload attribute due to unknown state version")
+		return false, emptyAttri, 0
 	}
-	return true, attr, proposerID, nil
+
+	return true, attr, proposerID
 }

 // removeInvalidBlockAndState removes the invalid block and its corresponding state from the cache and DB.
--- a/beacon-chain/blockchain/execution_engine_test.go
+++ b/beacon-chain/blockchain/execution_engine_test.go
@@ -15,12 +15,13 @@ import (
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
 	bstate "github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
+	state_native "github.com/prysmaticlabs/prysm/v3/beacon-chain/state/state-native"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
@@ -30,6 +31,69 @@ import (
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

+func Test_NotifyForkchoiceUpdate_GetPayloadAttrErrorCanContinue(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	altairBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockAltair())
+	altairBlkRoot, err := altairBlk.Block().HashTreeRoot()
+	require.NoError(t, err)
+	bellatrixBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockBellatrix())
+	bellatrixBlkRoot, err := bellatrixBlk.Block().HashTreeRoot()
+	require.NoError(t, err)
+	fcs := doublylinkedtree.New()
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB, fcs)),
+		WithForkChoiceStore(fcs),
+		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	st, _ := util.DeterministicGenesisState(t, 10)
+	service.head = &head{
+		state: st,
+	}
+
+	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+	state, blkRoot, err := prepareForkchoiceState(ctx, 0, [32]byte{}, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
+	state, blkRoot, err = prepareForkchoiceState(ctx, 1, altairBlkRoot, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
+	state, blkRoot, err = prepareForkchoiceState(ctx, 2, bellatrixBlkRoot, altairBlkRoot, params.BeaconConfig().ZeroHash, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
+
+	b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
+		Body: &ethpb.BeaconBlockBodyBellatrix{
+			ExecutionPayload: &v1.ExecutionPayload{},
+		},
+	})
+	require.NoError(t, err)
+
+	pid := &v1.PayloadIDBytes{1}
+	service.cfg.ExecutionEngineCaller = &mockExecution.EngineClient{PayloadIDBytes: pid}
+	st, _ = util.DeterministicGenesisState(t, 1)
+	require.NoError(t, beaconDB.SaveState(ctx, st, bellatrixBlkRoot))
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, bellatrixBlkRoot))
+
+	// Intentionally generate a bad state such that `hash_tree_root` fails during `process_slot`
+	s, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{})
+	require.NoError(t, err)
+	arg := &notifyForkchoiceUpdateArg{
+		headState: s,
+		headRoot:  [32]byte{},
+		headBlock: b,
+	}
+
+	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(1, 0, [8]byte{}, [32]byte{})
+	got, err := service.notifyForkchoiceUpdate(ctx, arg)
+	require.NoError(t, err)
+	require.DeepEqual(t, got, pid) // We still get a payload ID even though the state is bad. This means it returns until the end.
+}
+
 func Test_NotifyForkchoiceUpdate(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
@@ -47,11 +111,12 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
 	}
 	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
 	st, _ := util.DeterministicGenesisState(t, 10)
 	service.head = &head{
 		state: st,
 	}
-	require.NoError(t, err)
+
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	state, blkRoot, err := prepareForkchoiceState(ctx, 0, [32]byte{}, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
@@ -66,7 +131,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {

 	tests := []struct {
 		name             string
-		blk              interfaces.BeaconBlock
+		blk              interfaces.ReadOnlyBeaconBlock
 		headRoot         [32]byte
 		finalizedRoot    [32]byte
 		justifiedRoot    [32]byte
@@ -75,7 +140,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 	}{
 		{
 			name: "phase0 block",
-			blk: func() interfaces.BeaconBlock {
+			blk: func() interfaces.ReadOnlyBeaconBlock {
 				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}})
 				require.NoError(t, err)
 				return b
@@ -83,7 +148,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "altair block",
-			blk: func() interfaces.BeaconBlock {
+			blk: func() interfaces.ReadOnlyBeaconBlock {
 				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockAltair{Body: &ethpb.BeaconBlockBodyAltair{}})
 				require.NoError(t, err)
 				return b
@@ -91,7 +156,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "not execution block",
-			blk: func() interfaces.BeaconBlock {
+			blk: func() interfaces.ReadOnlyBeaconBlock {
 				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{
@@ -112,7 +177,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "happy case: finalized root is altair block",
-			blk: func() interfaces.BeaconBlock {
+			blk: func() interfaces.ReadOnlyBeaconBlock {
 				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
@@ -126,7 +191,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "happy case: finalized root is bellatrix block",
-			blk: func() interfaces.BeaconBlock {
+			blk: func() interfaces.ReadOnlyBeaconBlock {
 				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
@@ -140,7 +205,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "forkchoice updated with optimistic block",
-			blk: func() interfaces.BeaconBlock {
+			blk: func() interfaces.ReadOnlyBeaconBlock {
 				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
@@ -155,7 +220,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "forkchoice updated with invalid block",
-			blk: func() interfaces.BeaconBlock {
+			blk: func() interfaces.ReadOnlyBeaconBlock {
 				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
@@ -237,8 +302,8 @@ func Test_NotifyForkchoiceUpdate_NIlLVH(t *testing.T) {
 	service.cfg.ForkChoiceStore = fcs
 	service.cfg.ProposerSlotIndexCache = cache.NewProposerPayloadIDsCache()

-	service.justifiedBalances.balances = []uint64{50, 100, 200}
-	require.NoError(t, err)
+	fcs.SetBalancesByRooter(func(context.Context, [32]byte) ([]uint64, error) { return []uint64{50, 100, 200}, nil })
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{}))
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	state, blkRoot, err := prepareForkchoiceState(ctx, 1, bra, [32]byte{}, [32]byte{'A'}, ojc, ofc)
@@ -354,12 +419,15 @@ func Test_NotifyForkchoiceUpdateRecursive_DoublyLinkedTree(t *testing.T) {
 	service.cfg.ForkChoiceStore = fcs
 	service.cfg.ProposerSlotIndexCache = cache.NewProposerPayloadIDsCache()

-	service.justifiedBalances.balances = []uint64{50, 100, 200}
-	require.NoError(t, err)
+	fcs.SetBalancesByRooter(func(context.Context, [32]byte) ([]uint64, error) { return []uint64{50, 100, 200}, nil })
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{}))
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	state, blkRoot, err := prepareForkchoiceState(ctx, 1, bra, [32]byte{}, [32]byte{'A'}, ojc, ofc)
 	require.NoError(t, err)
+
+	bState, _ := util.DeterministicGenesisState(t, 10)
+	require.NoError(t, beaconDB.SaveState(ctx, bState, bra))
 	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
 	state, blkRoot, err = prepareForkchoiceState(ctx, 2, brb, bra, [32]byte{'B'}, ojc, ofc)
 	require.NoError(t, err)
@@ -385,9 +453,12 @@ func Test_NotifyForkchoiceUpdateRecursive_DoublyLinkedTree(t *testing.T) {
 	fcs.ProcessAttestation(ctx, []uint64{0}, brd, 1)
 	fcs.ProcessAttestation(ctx, []uint64{1}, brf, 1)
 	fcs.ProcessAttestation(ctx, []uint64{2}, brg, 1)
+	fcs.SetBalancesByRooter(service.cfg.StateGen.ActiveNonSlashedBalancesByRoot)
 	jc := &forkchoicetypes.Checkpoint{Epoch: 0, Root: bra}
-	require.NoError(t, fcs.UpdateJustifiedCheckpoint(jc))
-	headRoot, err := fcs.Head(ctx, []uint64{50, 100, 200})
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, jc))
+	fcs.SetBalancesByRooter(func(context.Context, [32]byte) ([]uint64, error) { return []uint64{50, 100, 200}, nil })
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{}))
+	headRoot, err := fcs.Head(ctx)
 	require.NoError(t, err)
 	require.Equal(t, brg, headRoot)

@@ -411,7 +482,7 @@ func Test_NotifyForkchoiceUpdateRecursive_DoublyLinkedTree(t *testing.T) {
 	require.Equal(t, brf, InvalidBlockRoot(err))

 	// Ensure Head is D
-	headRoot, err = fcs.Head(ctx, service.justifiedBalances.balances)
+	headRoot, err = fcs.Head(ctx)
 	require.NoError(t, err)
 	require.Equal(t, brd, headRoot)

@@ -483,7 +554,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 		postState      bstate.BeaconState
 		invalidBlock   bool
 		isValidPayload bool
-		blk            interfaces.SignedBeaconBlock
+		blk            interfaces.ReadOnlySignedBeaconBlock
 		newPayloadErr  error
 		errString      string
 		name           string
@@ -529,7 +600,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 		{
 			name:      "altair pre state, happy case",
 			postState: bellatrixState,
-			blk: func() interfaces.SignedBeaconBlock {
+			blk: func() interfaces.ReadOnlySignedBeaconBlock {
 				blk := &ethpb.SignedBeaconBlockBellatrix{
 					Block: &ethpb.BeaconBlockBellatrix{
 						Body: &ethpb.BeaconBlockBodyBellatrix{
@@ -548,7 +619,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 		{
 			name:      "not at merge transition",
 			postState: bellatrixState,
-			blk: func() interfaces.SignedBeaconBlock {
+			blk: func() interfaces.ReadOnlySignedBeaconBlock {
 				blk := &ethpb.SignedBeaconBlockBellatrix{
 					Block: &ethpb.BeaconBlockBellatrix{
 						Body: &ethpb.BeaconBlockBodyBellatrix{
@@ -574,7 +645,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 		{
 			name:      "happy case",
 			postState: bellatrixState,
-			blk: func() interfaces.SignedBeaconBlock {
+			blk: func() interfaces.ReadOnlySignedBeaconBlock {
 				blk := &ethpb.SignedBeaconBlockBellatrix{
 					Block: &ethpb.BeaconBlockBellatrix{
 						Body: &ethpb.BeaconBlockBodyBellatrix{
@@ -593,7 +664,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 		{
 			name:      "undefined error from ee",
 			postState: bellatrixState,
-			blk: func() interfaces.SignedBeaconBlock {
+			blk: func() interfaces.ReadOnlySignedBeaconBlock {
 				blk := &ethpb.SignedBeaconBlockBellatrix{
 					Block: &ethpb.BeaconBlockBellatrix{
 						Body: &ethpb.BeaconBlockBodyBellatrix{
@@ -613,7 +684,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 		{
 			name:      "invalid block hash error from ee",
 			postState: bellatrixState,
-			blk: func() interfaces.SignedBeaconBlock {
+			blk: func() interfaces.ReadOnlySignedBeaconBlock {
 				blk := &ethpb.SignedBeaconBlockBellatrix{
 					Block: &ethpb.BeaconBlockBellatrix{
 						Body: &ethpb.BeaconBlockBodyBellatrix{
@@ -727,33 +798,74 @@ func Test_GetPayloadAttribute(t *testing.T) {
 	// Cache miss
 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)
-	hasPayload, _, vId, err := service.getPayloadAttribute(ctx, nil, 0)
-	require.NoError(t, err)
+	st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
+	hasPayload, _, vId := service.getPayloadAttribute(ctx, st, 0)
 	require.Equal(t, false, hasPayload)
-	require.Equal(t, types.ValidatorIndex(0), vId)
+	require.Equal(t, primitives.ValidatorIndex(0), vId)

 	// Cache hit, advance state, no fee recipient
-	suggestedVid := types.ValidatorIndex(1)
-	slot := types.Slot(1)
+	suggestedVid := primitives.ValidatorIndex(1)
+	slot := primitives.Slot(1)
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
-	st, _ := util.DeterministicGenesisState(t, 1)
 	hook := logTest.NewGlobal()
-	hasPayload, attr, vId, err := service.getPayloadAttribute(ctx, st, slot)
-	require.NoError(t, err)
+	hasPayload, attr, vId := service.getPayloadAttribute(ctx, st, slot)
 	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedVid, vId)
-	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient).String())
+	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
 	require.LogsContain(t, hook, "Fee recipient is currently using the burn address")

 	// Cache hit, advance state, has fee recipient
 	suggestedAddr := common.HexToAddress("123")
-	require.NoError(t, service.cfg.BeaconDB.SaveFeeRecipientsByValidatorIDs(ctx, []types.ValidatorIndex{suggestedVid}, []common.Address{suggestedAddr}))
+	require.NoError(t, service.cfg.BeaconDB.SaveFeeRecipientsByValidatorIDs(ctx, []primitives.ValidatorIndex{suggestedVid}, []common.Address{suggestedAddr}))
 	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
-	hasPayload, attr, vId, err = service.getPayloadAttribute(ctx, st, slot)
-	require.NoError(t, err)
+	hasPayload, attr, vId = service.getPayloadAttribute(ctx, st, slot)
 	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedVid, vId)
-	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient))
+	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
+}
+
+func Test_GetPayloadAttributeV2(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
+		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
+	}
+
+	// Cache miss
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	st, _ := util.DeterministicGenesisStateCapella(t, 1)
+	hasPayload, _, vId := service.getPayloadAttribute(ctx, st, 0)
+	require.Equal(t, false, hasPayload)
+	require.Equal(t, primitives.ValidatorIndex(0), vId)
+
+	// Cache hit, advance state, no fee recipient
+	suggestedVid := primitives.ValidatorIndex(1)
+	slot := primitives.Slot(1)
+	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
+	hook := logTest.NewGlobal()
+	hasPayload, attr, vId := service.getPayloadAttribute(ctx, st, slot)
+	require.Equal(t, true, hasPayload)
+	require.Equal(t, suggestedVid, vId)
+	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
+	require.LogsContain(t, hook, "Fee recipient is currently using the burn address")
+	a, err := attr.Withdrawals()
+	require.NoError(t, err)
+	require.Equal(t, 0, len(a))
+
+	// Cache hit, advance state, has fee recipient
+	suggestedAddr := common.HexToAddress("123")
+	require.NoError(t, service.cfg.BeaconDB.SaveFeeRecipientsByValidatorIDs(ctx, []primitives.ValidatorIndex{suggestedVid}, []common.Address{suggestedAddr}))
+	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(slot, suggestedVid, [8]byte{}, [32]byte{})
+	hasPayload, attr, vId = service.getPayloadAttribute(ctx, st, slot)
+	require.Equal(t, true, hasPayload)
+	require.Equal(t, suggestedVid, vId)
+	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
+	a, err = attr.Withdrawals()
+	require.NoError(t, err)
+	require.Equal(t, 0, len(a))
 }

 func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
@@ -771,7 +883,7 @@ func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
 	}
 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)
-	genesisStateRoot := [32]byte{}
+	var genesisStateRoot [32]byte
 	genesisBlk := blocks.NewGenesisBlock(genesisStateRoot[:])
 	util.SaveBlock(t, ctx, beaconDB, genesisBlk)
 	genesisRoot, err := genesisBlk.Block.HashTreeRoot()
@@ -780,7 +892,7 @@ func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	fjc := &forkchoicetypes.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash}
-	require.NoError(t, fcs.UpdateJustifiedCheckpoint(fjc))
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, fjc))
 	require.NoError(t, fcs.UpdateFinalizedCheckpoint(fjc))
 	state, blkRoot, err := prepareForkchoiceState(ctx, 0, genesisRoot, params.BeaconConfig().ZeroHash, params.BeaconConfig().ZeroHash, ojc, ofc)
 	require.NoError(t, err)
@@ -847,6 +959,7 @@ func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
 	twentyfc := &ethpb.Checkpoint{Epoch: 20, Root: validRoot[:]}
 	state, blkRoot, err = prepareForkchoiceState(ctx, 640, validRoot, genesisRoot, params.BeaconConfig().ZeroHash, twentyjc, twentyfc)
 	require.NoError(t, err)
+	fcs.SetBalancesByRooter(func(_ context.Context, _ [32]byte) ([]uint64, error) { return []uint64{}, nil })
 	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
 	require.NoError(t, fcs.SetOptimisticToValid(ctx, validRoot))
 	assert.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, validRoot))
--- a/beacon-chain/blockchain/forkchoice_update_execution.go
+++ b/beacon-chain/blockchain/forkchoice_update_execution.go
@@ -0,0 +1,108 @@
+package blockchain
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v3/config/features"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+)
+
+func (s *Service) isNewProposer(slot primitives.Slot) bool {
+	_, _, ok := s.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(slot, [32]byte{} /* root */)
+	return ok
+}
+
+func (s *Service) isNewHead(r [32]byte) bool {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	currentHeadRoot := s.originBlockRoot
+	if s.head != nil {
+		currentHeadRoot = s.headRoot()
+	}
+
+	return r != currentHeadRoot || r == [32]byte{}
+}
+
+func (s *Service) getStateAndBlock(ctx context.Context, r [32]byte) (state.BeaconState, interfaces.ReadOnlySignedBeaconBlock, error) {
+	if !s.hasBlockInInitSyncOrDB(ctx, r) {
+		return nil, nil, errors.New("block does not exist")
+	}
+	newHeadBlock, err := s.getBlock(ctx, r)
+	if err != nil {
+		return nil, nil, err
+	}
+	headState, err := s.cfg.StateGen.StateByRoot(ctx, r)
+	if err != nil {
+		return nil, nil, err
+	}
+	return headState, newHeadBlock, nil
+}
+
+func (s *Service) forkchoiceUpdateWithExecution(ctx context.Context, newHeadRoot [32]byte, proposingSlot primitives.Slot) error {
+	isNewHead := s.isNewHead(newHeadRoot)
+	isNewProposer := s.isNewProposer(proposingSlot)
+	if !isNewHead && !isNewProposer {
+		return nil
+	}
+
+	var headState state.BeaconState
+	var headBlock interfaces.ReadOnlySignedBeaconBlock
+	var headRoot [32]byte
+	var err error
+
+	shouldUpdate := isNewHead
+	if isNewHead && isNewProposer && !features.Get().DisableReorgLateBlocks {
+		if proposingSlot == s.CurrentSlot() {
+			proposerHead := s.ForkChoicer().GetProposerHead()
+			if proposerHead != newHeadRoot {
+				shouldUpdate = false
+			}
+		} else if s.ForkChoicer().ShouldOverrideFCU() {
+			shouldUpdate = false
+		}
+	}
+	if shouldUpdate {
+		headRoot = newHeadRoot
+		headState, headBlock, err = s.getStateAndBlock(ctx, newHeadRoot)
+		if err != nil {
+			log.WithError(err).Error("Could not get forkchoice update argument")
+			return nil
+		}
+	} else {
+		// We are guaranteed that the head block is the parent
+		// of the incoming block. We do not process the slot
+		// because it will be processed anyway in notifyForkchoiceUpdate
+		headState = s.headState(ctx)
+		headRoot = s.headRoot()
+		headBlock, err = s.headBlock()
+		if err != nil {
+			return errors.Wrap(err, "could not get head block")
+		}
+	}
+
+	_, err = s.notifyForkchoiceUpdate(ctx, &notifyForkchoiceUpdateArg{
+		headState: headState,
+		headRoot:  headRoot,
+		headBlock: headBlock.Block(),
+	})
+	if err != nil {
+		return errors.Wrap(err, "could not notify forkchoice update")
+	}
+
+	if shouldUpdate {
+		if err := s.saveHead(ctx, newHeadRoot, headBlock, headState); err != nil {
+			log.WithError(err).Error("could not save head")
+		}
+
+		// Only need to prune attestations from pool if the head has changed.
+		if err := s.pruneAttsFromPool(headBlock); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
--- a/beacon-chain/blockchain/forkchoice_update_execution_test.go
+++ b/beacon-chain/blockchain/forkchoice_update_execution_test.go
@@ -0,0 +1,192 @@
+package blockchain
+
+import (
+	"context"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/cache"
+	testDB "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
+	mockExecution "github.com/prysmaticlabs/prysm/v3/beacon-chain/execution/testing"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/v3/config/params"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/testing/require"
+	"github.com/prysmaticlabs/prysm/v3/testing/util"
+	logTest "github.com/sirupsen/logrus/hooks/test"
+)
+
+func TestService_isNewProposer(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+	require.Equal(t, false, service.isNewProposer(service.CurrentSlot()+1))
+
+	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(service.CurrentSlot()+1, 0, [8]byte{}, [32]byte{} /* root */)
+	require.Equal(t, true, service.isNewProposer(service.CurrentSlot()+1))
+}
+
+func TestService_isNewHead(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+	require.Equal(t, true, service.isNewHead([32]byte{}))
+
+	service.head = &head{root: [32]byte{1}}
+	require.Equal(t, true, service.isNewHead([32]byte{2}))
+	require.Equal(t, false, service.isNewHead([32]byte{1}))
+
+	// Nil head should use origin root
+	service.head = nil
+	service.originBlockRoot = [32]byte{3}
+	require.Equal(t, true, service.isNewHead([32]byte{2}))
+	require.Equal(t, false, service.isNewHead([32]byte{3}))
+}
+
+func TestService_getHeadStateAndBlock(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+	_, _, err := service.getStateAndBlock(context.Background(), [32]byte{})
+	require.ErrorContains(t, "block does not exist", err)
+
+	blk, err := blocks.NewSignedBeaconBlock(util.HydrateSignedBeaconBlock(&ethpb.SignedBeaconBlock{Signature: []byte{1}}))
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), blk))
+
+	st, _ := util.DeterministicGenesisState(t, 1)
+	r, err := blk.Block().HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), st, r))
+
+	gotState, err := service.cfg.BeaconDB.State(context.Background(), r)
+	require.NoError(t, err)
+	require.DeepEqual(t, st.ToProto(), gotState.ToProto())
+
+	gotBlk, err := service.cfg.BeaconDB.Block(context.Background(), r)
+	require.NoError(t, err)
+	require.DeepEqual(t, blk, gotBlk)
+}
+
+func TestService_forkchoiceUpdateWithExecution_exceptionalCases(t *testing.T) {
+	hook := logTest.NewGlobal()
+	ctx := context.Background()
+	opts := testServiceOptsWithDB(t)
+
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	service.cfg.ProposerSlotIndexCache = cache.NewProposerPayloadIDsCache()
+	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, service.headRoot(), service.CurrentSlot()+1))
+	hookErr := "could not notify forkchoice update"
+	invalidStateErr := "could not get state summary: could not find block in DB"
+	require.LogsDoNotContain(t, hook, invalidStateErr)
+	require.LogsDoNotContain(t, hook, hookErr)
+	gb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlock())
+	require.NoError(t, err)
+	require.NoError(t, service.saveInitSyncBlock(ctx, [32]byte{'a'}, gb))
+	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, [32]byte{'a'}, service.CurrentSlot()+1))
+	require.LogsContain(t, hook, invalidStateErr)
+
+	hook.Reset()
+	service.head = &head{
+		root:  [32]byte{'a'},
+		block: nil, /* should not panic if notify head uses correct head */
+	}
+
+	// Block in Cache
+	b := util.NewBeaconBlock()
+	b.Block.Slot = 2
+	wsb, err := blocks.NewSignedBeaconBlock(b)
+	require.NoError(t, err)
+	r1, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, service.saveInitSyncBlock(ctx, r1, wsb))
+	st, _ := util.DeterministicGenesisState(t, 1)
+	service.head = &head{
+		root:  r1,
+		block: wsb,
+		state: st,
+	}
+	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(2, 1, [8]byte{1}, [32]byte{2})
+	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, r1, service.CurrentSlot()))
+	require.LogsDoNotContain(t, hook, invalidStateErr)
+	require.LogsDoNotContain(t, hook, hookErr)
+
+	// Block in DB
+	b = util.NewBeaconBlock()
+	b.Block.Slot = 3
+	util.SaveBlock(t, ctx, service.cfg.BeaconDB, b)
+	r1, err = b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	st, _ = util.DeterministicGenesisState(t, 1)
+	service.head = &head{
+		root:  r1,
+		block: wsb,
+		state: st,
+	}
+	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(2, 1, [8]byte{1}, [32]byte{2})
+	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, r1, service.CurrentSlot()+1))
+	require.LogsDoNotContain(t, hook, invalidStateErr)
+	require.LogsDoNotContain(t, hook, hookErr)
+	vId, payloadID, has := service.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(2, [32]byte{2})
+	require.Equal(t, true, has)
+	require.Equal(t, primitives.ValidatorIndex(1), vId)
+	require.Equal(t, [8]byte{1}, payloadID)
+
+	// Test zero headRoot returns immediately.
+	headRoot := service.headRoot()
+	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, [32]byte{}, service.CurrentSlot()+1))
+	require.Equal(t, service.headRoot(), headRoot)
+}
+
+func TestService_forkchoiceUpdateWithExecution_SameHeadRootNewProposer(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	altairBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockAltair())
+	altairBlkRoot, err := altairBlk.Block().HashTreeRoot()
+	require.NoError(t, err)
+	bellatrixBlk := util.SaveBlock(t, ctx, beaconDB, util.NewBeaconBlockBellatrix())
+	bellatrixBlkRoot, err := bellatrixBlk.Block().HashTreeRoot()
+	require.NoError(t, err)
+	fcs := doublylinkedtree.New()
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB, fcs)),
+		WithForkChoiceStore(fcs),
+		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	st, _ := util.DeterministicGenesisState(t, 10)
+	service.head = &head{
+		state: st,
+	}
+
+	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+	state, blkRoot, err := prepareForkchoiceState(ctx, 0, [32]byte{}, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
+	state, blkRoot, err = prepareForkchoiceState(ctx, 1, altairBlkRoot, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
+	state, blkRoot, err = prepareForkchoiceState(ctx, 2, bellatrixBlkRoot, altairBlkRoot, params.BeaconConfig().ZeroHash, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))
+
+	service.cfg.ExecutionEngineCaller = &mockExecution.EngineClient{}
+	require.NoError(t, beaconDB.SaveState(ctx, st, bellatrixBlkRoot))
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, bellatrixBlkRoot))
+	sb, err := blocks.NewSignedBeaconBlock(util.HydrateSignedBeaconBlockBellatrix(&ethpb.SignedBeaconBlockBellatrix{}))
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, sb))
+	r, err := sb.Block().HashTreeRoot()
+	require.NoError(t, err)
+
+	// Set head to be the same but proposing next slot
+	service.head.root = r
+	service.head.block = sb
+	service.head.state = st
+	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(service.CurrentSlot()+1, 0, [8]byte{}, [32]byte{} /* root */)
+	require.NoError(t, service.forkchoiceUpdateWithExecution(ctx, r, service.CurrentSlot()+1))
+
+}
--- a/beacon-chain/blockchain/head.go
+++ b/beacon-chain/blockchain/head.go
@@ -15,10 +15,11 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v3/math"
 	ethpbv1 "github.com/prysmaticlabs/prysm/v3/proto/eth/v1"
+	"github.com/prysmaticlabs/prysm/v3/runtime/version"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
@@ -27,14 +28,7 @@ import (
 // UpdateAndSaveHeadWithBalances updates the beacon state head after getting justified balanced from cache.
 // This function is only used in spec-tests, it does save the head after updating it.
 func (s *Service) UpdateAndSaveHeadWithBalances(ctx context.Context) error {
-	jp := s.CurrentJustifiedCheckpt()
-
-	balances, err := s.justifiedBalances.get(ctx, bytesutil.ToBytes32(jp.Root))
-	if err != nil {
-		msg := fmt.Sprintf("could not read balances for state w/ justified checkpoint %#x", jp.Root)
-		return errors.Wrap(err, msg)
-	}
-	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx, balances)
+	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not update head")
 	}
@@ -51,30 +45,24 @@ func (s *Service) UpdateAndSaveHeadWithBalances(ctx context.Context) error {

 // This defines the current chain service's view of head.
 type head struct {
-	slot  types.Slot                   // current head slot.
-	root  [32]byte                     // current head root.
-	block interfaces.SignedBeaconBlock // 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.
+	lastTick primitives.Slot
 }

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

 	// Do nothing if head hasn't changed.
-	var oldHeadRoot [32]byte
-	s.headLock.RLock()
-	if s.head == nil {
-		oldHeadRoot = s.originBlockRoot
-	} else {
-		oldHeadRoot = s.head.root
-	}
-	s.headLock.RUnlock()
-	if newHeadRoot == oldHeadRoot {
+	if !s.isNewHead(newHeadRoot) {
 		return nil
 	}
+
 	if err := blocks.BeaconBlockIsNil(headBlock); err != nil {
 		return err
 	}
@@ -101,6 +89,11 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 	newStateRoot := headBlock.Block().StateRoot()

 	// A chain re-org occurred, so we fire an event notifying the rest of the services.
+	r, err := s.HeadRoot(ctx)
+	if err != nil {
+		return errors.Wrap(err, "could not get old head root")
+	}
+	oldHeadRoot := bytesutil.ToBytes32(r)
 	if headBlock.Block().ParentRoot() != oldHeadRoot {
 		commonRoot, forkSlot, err := s.ForkChoicer().CommonAncestor(ctx, oldHeadRoot, newHeadRoot)
 		if err != nil {
@@ -109,11 +102,21 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 		}
 		dis := headSlot + newHeadSlot - 2*forkSlot
 		dep := math.Max(uint64(headSlot-forkSlot), uint64(newHeadSlot-forkSlot))
+		oldWeight, err := s.ForkChoicer().Weight(oldHeadRoot)
+		if err != nil {
+			log.WithField("root", fmt.Sprintf("%#x", oldHeadRoot)).Warn("could not determine node weight")
+		}
+		newWeight, err := s.ForkChoicer().Weight(newHeadRoot)
+		if err != nil {
+			log.WithField("root", fmt.Sprintf("%#x", newHeadRoot)).Warn("could not determine node weight")
+		}
 		log.WithFields(logrus.Fields{
 			"newSlot":            fmt.Sprintf("%d", newHeadSlot),
 			"newRoot":            fmt.Sprintf("%#x", newHeadRoot),
+			"newWeight":          newWeight,
 			"oldSlot":            fmt.Sprintf("%d", headSlot),
 			"oldRoot":            fmt.Sprintf("%#x", oldHeadRoot),
+			"oldWeight":          oldWeight,
 			"commonAncestorRoot": fmt.Sprintf("%#x", commonRoot),
 			"distance":           dis,
 			"depth":              dep,
@@ -121,7 +124,7 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 		reorgDistance.Observe(float64(dis))
 		reorgDepth.Observe(float64(dep))

-		isOptimistic, err := s.IsOptimistic(ctx)
+		isOptimistic, err := s.ForkChoicer().IsOptimistic(newHeadRoot)
 		if err != nil {
 			return errors.Wrap(err, "could not check if node is optimistically synced")
 		}
@@ -139,7 +142,7 @@ func (s *Service) saveHead(ctx context.Context, newHeadRoot [32]byte, headBlock
 			},
 		})

-		if err := s.saveOrphanedAtts(ctx, oldHeadRoot, newHeadRoot); err != nil {
+		if err := s.saveOrphanedOperations(ctx, oldHeadRoot, newHeadRoot); err != nil {
 			return err
 		}
 		reorgCount.Inc()
@@ -169,7 +172,7 @@ 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.SignedBeaconBlock, r [32]byte, hs state.BeaconState) error {
+func (s *Service) saveHeadNoDB(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock, r [32]byte, hs state.BeaconState) error {
 	if err := blocks.BeaconBlockIsNil(b); err != nil {
 		return err
 	}
@@ -192,7 +195,7 @@ func (s *Service) saveHeadNoDB(ctx context.Context, b interfaces.SignedBeaconBlo
 }

 // 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.SignedBeaconBlock, state state.BeaconState) error {
+func (s *Service) setHead(root [32]byte, block interfaces.ReadOnlySignedBeaconBlock, state state.BeaconState) error {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -202,7 +205,6 @@ func (s *Service) setHead(root [32]byte, block interfaces.SignedBeaconBlock, sta
 		return err
 	}
 	s.head = &head{
-		slot:  block.Block().Slot(),
 		root:  root,
 		block: bCp,
 		state: state.Copy(),
@@ -213,7 +215,7 @@ func (s *Service) setHead(root [32]byte, block interfaces.SignedBeaconBlock, sta
 // 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.SignedBeaconBlock, state state.BeaconState) error {
+func (s *Service) setHeadInitialSync(root [32]byte, block interfaces.ReadOnlySignedBeaconBlock, state state.BeaconState) error {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -223,7 +225,6 @@ func (s *Service) setHeadInitialSync(root [32]byte, block interfaces.SignedBeaco
 		return err
 	}
 	s.head = &head{
-		slot:  block.Block().Slot(),
 		root:  root,
 		block: bCp,
 		state: state,
@@ -233,8 +234,11 @@ func (s *Service) setHeadInitialSync(root [32]byte, block interfaces.SignedBeaco

 // This returns the head slot.
 // This is a lock free version.
-func (s *Service) headSlot() types.Slot {
-	return s.head.slot
+func (s *Service) headSlot() primitives.Slot {
+	if s.head == nil || s.head.block == nil || s.head.block.Block() == nil {
+		return 0
+	}
+	return s.head.block.Block().Slot()
 }

 // This returns the head root.
@@ -248,10 +252,16 @@ func (s *Service) headRoot() [32]byte {
 	return s.head.root
 }

+// This returns the last slot where we have processed attestations
+// This is a lock free version
+func (s *Service) lastTick() primitives.Slot {
+	return s.head.lastTick
+}
+
 // This returns the head block.
 // It does a full copy on head block for immutability.
 // This is a lock free version.
-func (s *Service) headBlock() (interfaces.SignedBeaconBlock, error) {
+func (s *Service) headBlock() (interfaces.ReadOnlySignedBeaconBlock, error) {
 	return s.head.block.Copy()
 }

@@ -265,6 +275,16 @@ func (s *Service) headState(ctx context.Context) state.BeaconState {
 	return s.head.state.Copy()
 }

+// This returns a read only version of the head state.
+// It does not perform a copy of the head state.
+// This is a lock free version.
+func (s *Service) headStateReadOnly(ctx context.Context) state.ReadOnlyBeaconState {
+	ctx, span := trace.StartSpan(ctx, "blockChain.headStateReadOnly")
+	defer span.End()
+
+	return s.head.state
+}
+
 // This returns the genesis validators root of the head state.
 // This is a lock free version.
 func (s *Service) headGenesisValidatorsRoot() [32]byte {
@@ -274,14 +294,14 @@ func (s *Service) headGenesisValidatorsRoot() [32]byte {
 // This returns the validator referenced by the provided index in
 // the head state.
 // This is a lock free version.
-func (s *Service) headValidatorAtIndex(index types.ValidatorIndex) (state.ReadOnlyValidator, error) {
+func (s *Service) headValidatorAtIndex(index primitives.ValidatorIndex) (state.ReadOnlyValidator, error) {
 	return s.head.state.ValidatorAtIndexReadOnly(index)
 }

 // This returns the validator index referenced by the provided pubkey in
 // the head state.
 // This is a lock free version.
-func (s *Service) headValidatorIndexAtPubkey(pubKey [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool) {
+func (s *Service) headValidatorIndexAtPubkey(pubKey [fieldparams.BLSPubkeyLength]byte) (primitives.ValidatorIndex, bool) {
 	return s.head.state.ValidatorIndexByPubkey(pubKey)
 }

@@ -295,7 +315,7 @@ func (s *Service) hasHeadState() bool {
 // chain head is determined, set, and saved to disk.
 func (s *Service) notifyNewHeadEvent(
 	ctx context.Context,
-	newHeadSlot types.Slot,
+	newHeadSlot primitives.Slot,
 	newHeadState state.BeaconState,
 	newHeadStateRoot,
 	newHeadRoot []byte,
@@ -303,7 +323,7 @@ func (s *Service) notifyNewHeadEvent(
 	previousDutyDependentRoot := s.originBlockRoot[:]
 	currentDutyDependentRoot := s.originBlockRoot[:]

-	var previousDutyEpoch types.Epoch
+	var previousDutyEpoch primitives.Epoch
 	currentDutyEpoch := slots.ToEpoch(newHeadSlot)
 	if currentDutyEpoch > 0 {
 		previousDutyEpoch = currentDutyEpoch.Sub(1)
@@ -347,9 +367,9 @@ func (s *Service) notifyNewHeadEvent(
 	return nil
 }

-// This saves the attestations between `orphanedRoot` and the common ancestor root that is derived using `newHeadRoot`.
+// This saves the Attestations and BLSToExecChanges between `orphanedRoot` and the common ancestor root that is derived using `newHeadRoot`.
 // It also filters out the attestations that is one epoch older as a defense so invalid attestations don't flow into the attestation pool.
-func (s *Service) saveOrphanedAtts(ctx context.Context, orphanedRoot [32]byte, newHeadRoot [32]byte) error {
+func (s *Service) saveOrphanedOperations(ctx context.Context, orphanedRoot [32]byte, newHeadRoot [32]byte) error {
 	commonAncestorRoot, _, err := s.ForkChoicer().CommonAncestor(ctx, newHeadRoot, orphanedRoot)
 	switch {
 	// Exit early if there's no common ancestor and root doesn't exist, there would be nothing to save.
@@ -388,6 +408,15 @@ func (s *Service) saveOrphanedAtts(ctx context.Context, orphanedRoot [32]byte, n
 			}
 			saveOrphanedAttCount.Inc()
 		}
+		if orphanedBlk.Version() >= version.Capella {
+			changes, err := orphanedBlk.Block().Body().BLSToExecutionChanges()
+			if err != nil {
+				return errors.Wrap(err, "could not get BLSToExecutionChanges")
+			}
+			for _, c := range changes {
+				s.cfg.BLSToExecPool.InsertBLSToExecChange(c)
+			}
+		}
 		parentRoot := orphanedBlk.Block().ParentRoot()
 		orphanedRoot = bytesutil.ToBytes32(parentRoot[:])
 	}
--- a/beacon-chain/blockchain/head_sync_committee_info.go
+++ b/beacon-chain/blockchain/head_sync_committee_info.go
@@ -13,7 +13,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 )
@@ -24,30 +24,30 @@ var syncCommitteeHeadStateCache = cache.NewSyncCommitteeHeadState()
 // HeadSyncCommitteeFetcher is the interface that wraps the head sync committee related functions.
 // The head sync committee functions return callers sync committee indices and public keys with respect to current head state.
 type HeadSyncCommitteeFetcher interface {
-	HeadSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error)
-	HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot, committeeIndex types.CommitteeIndex) ([][]byte, error)
+	HeadSyncCommitteeIndices(ctx context.Context, index primitives.ValidatorIndex, slot primitives.Slot) ([]primitives.CommitteeIndex, error)
+	HeadSyncCommitteePubKeys(ctx context.Context, slot primitives.Slot, committeeIndex primitives.CommitteeIndex) ([][]byte, error)
 }

 // HeadDomainFetcher is the interface that wraps the head sync domain related functions.
 // The head sync committee domain functions return callers domain data with respect to slot and head state.
 type HeadDomainFetcher interface {
-	HeadSyncCommitteeDomain(ctx context.Context, slot types.Slot) ([]byte, error)
-	HeadSyncSelectionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error)
-	HeadSyncContributionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error)
+	HeadSyncCommitteeDomain(ctx context.Context, slot primitives.Slot) ([]byte, error)
+	HeadSyncSelectionProofDomain(ctx context.Context, slot primitives.Slot) ([]byte, error)
+	HeadSyncContributionProofDomain(ctx context.Context, slot primitives.Slot) ([]byte, error)
 }

 // HeadSyncCommitteeDomain returns the head sync committee domain using current head state advanced up to `slot`.
-func (s *Service) HeadSyncCommitteeDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+func (s *Service) HeadSyncCommitteeDomain(ctx context.Context, slot primitives.Slot) ([]byte, error) {
 	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainSyncCommittee)
 }

 // HeadSyncSelectionProofDomain returns the head sync committee domain using current head state advanced up to `slot`.
-func (s *Service) HeadSyncSelectionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+func (s *Service) HeadSyncSelectionProofDomain(ctx context.Context, slot primitives.Slot) ([]byte, error) {
 	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainSyncCommitteeSelectionProof)
 }

 // HeadSyncContributionProofDomain returns the head sync committee domain using current head state advanced up to `slot`.
-func (s *Service) HeadSyncContributionProofDomain(ctx context.Context, slot types.Slot) ([]byte, error) {
+func (s *Service) HeadSyncContributionProofDomain(ctx context.Context, slot primitives.Slot) ([]byte, error) {
 	return s.domainWithHeadState(ctx, slot, params.BeaconConfig().DomainContributionAndProof)
 }

@@ -61,7 +61,7 @@ func (s *Service) HeadSyncContributionProofDomain(ctx context.Context, slot type
 // [compute_start_slot_at_epoch(epoch) - 1, compute_start_slot_at_epoch(epoch) + SLOTS_PER_EPOCH - 1)
 // rather than for the range
 // [compute_start_slot_at_epoch(epoch), compute_start_slot_at_epoch(epoch) + SLOTS_PER_EPOCH)
-func (s *Service) HeadSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
+func (s *Service) HeadSyncCommitteeIndices(ctx context.Context, index primitives.ValidatorIndex, slot primitives.Slot) ([]primitives.CommitteeIndex, error) {
 	nextSlotEpoch := slots.ToEpoch(slot + 1)
 	currentEpoch := slots.ToEpoch(slot)

@@ -79,7 +79,7 @@ func (s *Service) HeadSyncCommitteeIndices(ctx context.Context, index types.Vali

 // headCurrentSyncCommitteeIndices returns the input validator `index`'s position indices in the current sync committee with respect to `slot`.
 // Head state advanced up to `slot` is used for calculation.
-func (s *Service) headCurrentSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
+func (s *Service) headCurrentSyncCommitteeIndices(ctx context.Context, index primitives.ValidatorIndex, slot primitives.Slot) ([]primitives.CommitteeIndex, error) {
 	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
 	if err != nil {
 		return nil, err
@@ -89,7 +89,7 @@ func (s *Service) headCurrentSyncCommitteeIndices(ctx context.Context, index typ

 // headNextSyncCommitteeIndices returns the input validator `index`'s position indices in the next sync committee with respect to `slot`.
 // Head state advanced up to `slot` is used for calculation.
-func (s *Service) headNextSyncCommitteeIndices(ctx context.Context, index types.ValidatorIndex, slot types.Slot) ([]types.CommitteeIndex, error) {
+func (s *Service) headNextSyncCommitteeIndices(ctx context.Context, index primitives.ValidatorIndex, slot primitives.Slot) ([]primitives.CommitteeIndex, error) {
 	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
 	if err != nil {
 		return nil, err
@@ -99,7 +99,7 @@ func (s *Service) headNextSyncCommitteeIndices(ctx context.Context, index types.

 // HeadSyncCommitteePubKeys returns the head sync committee public keys with respect to `slot` and subcommittee index `committeeIndex`.
 // Head state advanced up to `slot` is used for calculation.
-func (s *Service) HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot, committeeIndex types.CommitteeIndex) ([][]byte, error) {
+func (s *Service) HeadSyncCommitteePubKeys(ctx context.Context, slot primitives.Slot, committeeIndex primitives.CommitteeIndex) ([][]byte, error) {
 	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
 	if err != nil {
 		return nil, err
@@ -125,7 +125,7 @@ func (s *Service) HeadSyncCommitteePubKeys(ctx context.Context, slot types.Slot,
 }

 // returns calculated domain using input `domain` and `slot`.
-func (s *Service) domainWithHeadState(ctx context.Context, slot types.Slot, domain [4]byte) ([]byte, error) {
+func (s *Service) domainWithHeadState(ctx context.Context, slot primitives.Slot, domain [4]byte) ([]byte, error) {
 	headState, err := s.getSyncCommitteeHeadState(ctx, slot)
 	if err != nil {
 		return nil, err
@@ -135,7 +135,7 @@ func (s *Service) domainWithHeadState(ctx context.Context, slot types.Slot, doma

 // returns the head state that is advanced up to `slot`. It utilizes the cache `syncCommitteeHeadState` by retrieving using `slot` as key.
 // For the cache miss, it processes head state up to slot and fill the cache with `slot` as key.
-func (s *Service) getSyncCommitteeHeadState(ctx context.Context, slot types.Slot) (state.BeaconState, error) {
+func (s *Service) getSyncCommitteeHeadState(ctx context.Context, slot primitives.Slot) (state.BeaconState, error) {
 	var headState state.BeaconState
 	var err error
 	mLock := async.NewMultilock(fmt.Sprintf("%s-%d", "syncHeadState", slot))
--- a/beacon-chain/blockchain/head_sync_committee_info_test.go
+++ b/beacon-chain/blockchain/head_sync_committee_info_test.go
@@ -6,52 +6,13 @@ import (

 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/signing"
-	dbtest "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 	"github.com/prysmaticlabs/prysm/v3/testing/util"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 )

-func TestService_headSyncCommitteeFetcher_Errors(t *testing.T) {
-	beaconDB := dbtest.SetupDB(t)
-	c := &Service{
-		cfg: &config{
-			StateGen: stategen.New(beaconDB, doublylinkedtree.New()),
-		},
-	}
-	c.head = &head{}
-	_, err := c.headCurrentSyncCommitteeIndices(context.Background(), types.ValidatorIndex(0), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.headNextSyncCommitteeIndices(context.Background(), types.ValidatorIndex(0), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.HeadSyncCommitteePubKeys(context.Background(), types.Slot(0), types.CommitteeIndex(0))
-	require.ErrorContains(t, "nil state", err)
-}
-
-func TestService_HeadDomainFetcher_Errors(t *testing.T) {
-	beaconDB := dbtest.SetupDB(t)
-	c := &Service{
-		cfg: &config{
-			StateGen: stategen.New(beaconDB, doublylinkedtree.New()),
-		},
-	}
-	c.head = &head{}
-	_, err := c.HeadSyncCommitteeDomain(context.Background(), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.HeadSyncSelectionProofDomain(context.Background(), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-
-	_, err = c.HeadSyncSelectionProofDomain(context.Background(), types.Slot(0))
-	require.ErrorContains(t, "nil state", err)
-}
-
 func TestService_HeadSyncCommitteeIndices(t *testing.T) {
 	s, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().TargetCommitteeSize)
 	c := &Service{}
@@ -59,18 +20,18 @@ func TestService_HeadSyncCommitteeIndices(t *testing.T) {

 	// Current period
 	slot := 2*uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	a, err := c.HeadSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
+	a, err := c.HeadSyncCommitteeIndices(context.Background(), 0, primitives.Slot(slot))
 	require.NoError(t, err)

 	// Current period where slot-2 across EPOCHS_PER_SYNC_COMMITTEE_PERIOD
 	slot = 3*uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) - 2
-	b, err := c.HeadSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
+	b, err := c.HeadSyncCommitteeIndices(context.Background(), 0, primitives.Slot(slot))
 	require.NoError(t, err)
 	require.DeepEqual(t, a, b)

 	// Next period where slot-1 across EPOCHS_PER_SYNC_COMMITTEE_PERIOD
 	slot = 3*uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) - 1
-	b, err = c.HeadSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
+	b, err = c.HeadSyncCommitteeIndices(context.Background(), 0, primitives.Slot(slot))
 	require.NoError(t, err)
 	require.DeepNotEqual(t, a, b)
 }
@@ -82,7 +43,7 @@ func TestService_headCurrentSyncCommitteeIndices(t *testing.T) {

 	// Process slot up to `EpochsPerSyncCommitteePeriod` so it can `ProcessSyncCommitteeUpdates`.
 	slot := uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	indices, err := c.headCurrentSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
+	indices, err := c.headCurrentSyncCommitteeIndices(context.Background(), 0, primitives.Slot(slot))
 	require.NoError(t, err)

 	// NextSyncCommittee becomes CurrentSyncCommittee so it should be empty by default.
@@ -96,7 +57,7 @@ func TestService_headNextSyncCommitteeIndices(t *testing.T) {

 	// Process slot up to `EpochsPerSyncCommitteePeriod` so it can `ProcessSyncCommitteeUpdates`.
 	slot := uint64(params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	indices, err := c.headNextSyncCommitteeIndices(context.Background(), 0, types.Slot(slot))
+	indices, err := c.headNextSyncCommitteeIndices(context.Background(), 0, primitives.Slot(slot))
 	require.NoError(t, err)

 	// NextSyncCommittee should be be empty after `ProcessSyncCommitteeUpdates`. Validator should get indices.
@@ -110,7 +71,7 @@ func TestService_HeadSyncCommitteePubKeys(t *testing.T) {

 	// Process slot up to 2 * `EpochsPerSyncCommitteePeriod` so it can run `ProcessSyncCommitteeUpdates` twice.
 	slot := uint64(2*params.BeaconConfig().EpochsPerSyncCommitteePeriod)*uint64(params.BeaconConfig().SlotsPerEpoch) + 1
-	pubkeys, err := c.HeadSyncCommitteePubKeys(context.Background(), types.Slot(slot), 0)
+	pubkeys, err := c.HeadSyncCommitteePubKeys(context.Background(), primitives.Slot(slot), 0)
 	require.NoError(t, err)

 	// Any subcommittee should match the subcommittee size.
--- a/beacon-chain/blockchain/head_test.go
+++ b/beacon-chain/blockchain/head_test.go
@@ -10,11 +10,13 @@ import (
 	mock "github.com/prysmaticlabs/prysm/v3/beacon-chain/blockchain/testing"
 	testDB "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/blstoexec"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v3/config/features"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpbv1 "github.com/prysmaticlabs/prysm/v3/proto/eth/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
@@ -30,12 +32,12 @@ func TestSaveHead_Same(t *testing.T) {
 	service := setupBeaconChain(t, beaconDB)

 	r := [32]byte{'A'}
-	service.head = &head{slot: 0, root: r}
+	service.head = &head{root: r}
 	b, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlock())
 	require.NoError(t, err)
 	st, _ := util.DeterministicGenesisState(t, 1)
 	require.NoError(t, service.saveHead(context.Background(), r, b, st))
-	assert.Equal(t, types.Slot(0), service.headSlot(), "Head did not stay the same")
+	assert.Equal(t, primitives.Slot(0), service.headSlot(), "Head did not stay the same")
 	assert.Equal(t, r, service.headRoot(), "Head did not stay the same")
 }

@@ -53,7 +55,6 @@ func TestSaveHead_Different(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
 	service.head = &head{
-		slot:  0,
 		root:  oldRoot,
 		block: oldBlock,
 	}
@@ -79,7 +80,7 @@ func TestSaveHead_Different(t *testing.T) {
 	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), headState, newRoot))
 	require.NoError(t, service.saveHead(context.Background(), newRoot, wsb, headState))

-	assert.Equal(t, types.Slot(1), service.HeadSlot(), "Head did not change")
+	assert.Equal(t, primitives.Slot(1), service.HeadSlot(), "Head did not change")

 	cachedRoot, err := service.HeadRoot(context.Background())
 	require.NoError(t, err)
@@ -107,7 +108,6 @@ func TestSaveHead_Different_Reorg(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
 	service.head = &head{
-		slot:  0,
 		root:  oldRoot,
 		block: oldBlock,
 	}
@@ -135,7 +135,7 @@ func TestSaveHead_Different_Reorg(t *testing.T) {
 	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), headState, newRoot))
 	require.NoError(t, service.saveHead(context.Background(), newRoot, wsb, headState))

-	assert.Equal(t, types.Slot(1), service.HeadSlot(), "Head did not change")
+	assert.Equal(t, primitives.Slot(1), service.HeadSlot(), "Head did not change")

 	cachedRoot, err := service.HeadRoot(context.Background())
 	require.NoError(t, err)
@@ -153,20 +153,6 @@ func TestSaveHead_Different_Reorg(t *testing.T) {
 	require.LogsContain(t, hook, "depth=1")
 }

-func TestCacheJustifiedStateBalances_CanCache(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	service := setupBeaconChain(t, beaconDB)
-	ctx := context.Background()
-
-	state, _ := util.DeterministicGenesisState(t, 100)
-	r := [32]byte{'a'}
-	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: r[:]}))
-	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), state, r))
-	balances, err := service.justifiedBalances.get(ctx, r)
-	require.NoError(t, err)
-	require.DeepEqual(t, balances, state.Balances(), "Incorrect justified balances")
-}
-
 func Test_notifyNewHeadEvent(t *testing.T) {
 	t.Run("genesis_state_root", func(t *testing.T) {
 		bState, _ := util.DeterministicGenesisState(t, 10)
@@ -233,6 +219,48 @@ func Test_notifyNewHeadEvent(t *testing.T) {
 	})
 }

+func TestRetrieveHead_ReadOnly(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+
+	oldBlock := util.SaveBlock(t, context.Background(), service.cfg.BeaconDB, util.NewBeaconBlock())
+	oldRoot, err := oldBlock.Block().HashTreeRoot()
+	require.NoError(t, err)
+	service.head = &head{
+		root:  oldRoot,
+		block: oldBlock,
+	}
+
+	newHeadSignedBlock := util.NewBeaconBlock()
+	newHeadSignedBlock.Block.Slot = 1
+	newHeadBlock := newHeadSignedBlock.Block
+	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
+
+	wsb := util.SaveBlock(t, context.Background(), service.cfg.BeaconDB, newHeadSignedBlock)
+	newRoot, err := newHeadBlock.HashTreeRoot()
+	require.NoError(t, err)
+	state, blkRoot, err := prepareForkchoiceState(ctx, wsb.Block().Slot()-1, wsb.Block().ParentRoot(), service.cfg.ForkChoiceStore.CachedHeadRoot(), [32]byte{}, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
+
+	state, blkRoot, err = prepareForkchoiceState(ctx, wsb.Block().Slot(), newRoot, wsb.Block().ParentRoot(), [32]byte{}, ojc, ofc)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
+	headState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetSlot(1))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Slot: 1, Root: newRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), headState, newRoot))
+	require.NoError(t, service.saveHead(context.Background(), newRoot, wsb, headState))
+
+	rOnlyState, err := service.HeadStateReadOnly(ctx)
+	require.NoError(t, err)
+
+	assert.Equal(t, rOnlyState, service.head.state, "Head is not the same object")
+}
+
 func TestSaveOrphanedAtts(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
@@ -285,7 +313,7 @@ func TestSaveOrphanedAtts(t *testing.T) {
 		util.SaveBlock(t, ctx, beaconDB, blk)
 	}

-	require.NoError(t, service.saveOrphanedAtts(ctx, r3, r4))
+	require.NoError(t, service.saveOrphanedOperations(ctx, r3, r4))
 	require.Equal(t, 3, service.cfg.AttPool.AggregatedAttestationCount())
 	wantAtts := []*ethpb.Attestation{
 		blk3.Block.Body.Attestations[0],
@@ -303,31 +331,37 @@ func TestSaveOrphanedAtts_CanFilter(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 	service := setupBeaconChain(t, beaconDB)
+	service.cfg.BLSToExecPool = blstoexec.NewPool()
 	service.genesisTime = time.Now().Add(time.Duration(-1*int64(params.BeaconConfig().SlotsPerEpoch+2)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)

 	// Chain setup
 	// 0 -- 1 -- 2
 	//  \-4
-	st, keys := util.DeterministicGenesisState(t, 64)
-	blkG, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 0)
+	st, keys := util.DeterministicGenesisStateCapella(t, 64)
+	blkConfig := util.DefaultBlockGenConfig()
+	blkConfig.NumBLSChanges = 5
+	blkG, err := util.GenerateFullBlockCapella(st, keys, blkConfig, 1)
 	assert.NoError(t, err)
 	util.SaveBlock(t, ctx, service.cfg.BeaconDB, blkG)
 	rG, err := blkG.Block.HashTreeRoot()
 	require.NoError(t, err)

-	blk1, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 1)
+	blkConfig.NumBLSChanges = 10
+	blk1, err := util.GenerateFullBlockCapella(st, keys, blkConfig, 2)
 	assert.NoError(t, err)
 	blk1.Block.ParentRoot = rG[:]
 	r1, err := blk1.Block.HashTreeRoot()
 	require.NoError(t, err)

-	blk2, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), 2)
+	blkConfig.NumBLSChanges = 15
+	blk2, err := util.GenerateFullBlockCapella(st, keys, blkConfig, 3)
 	assert.NoError(t, err)
 	blk2.Block.ParentRoot = r1[:]
 	r2, err := blk2.Block.HashTreeRoot()
 	require.NoError(t, err)

-	blk4 := util.NewBeaconBlock()
+	blk4 := util.NewBeaconBlockCapella()
+	blkConfig.NumBLSChanges = 0
 	blk4.Block.Slot = 4
 	blk4.Block.ParentRoot = rG[:]
 	r4, err := blk4.Block.HashTreeRoot()
@@ -335,7 +369,7 @@ func TestSaveOrphanedAtts_CanFilter(t *testing.T) {
 	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}

-	for _, blk := range []*ethpb.SignedBeaconBlock{blkG, blk1, blk2, blk4} {
+	for _, blk := range []*ethpb.SignedBeaconBlockCapella{blkG, blk1, blk2, blk4} {
 		r, err := blk.Block.HashTreeRoot()
 		require.NoError(t, err)
 		state, blkRoot, err := prepareForkchoiceState(ctx, blk.Block.Slot, r, bytesutil.ToBytes32(blk.Block.ParentRoot), [32]byte{}, ojc, ofc)
@@ -344,8 +378,11 @@ func TestSaveOrphanedAtts_CanFilter(t *testing.T) {
 		util.SaveBlock(t, ctx, beaconDB, blk)
 	}

-	require.NoError(t, service.saveOrphanedAtts(ctx, r2, r4))
-	require.Equal(t, 0, service.cfg.AttPool.AggregatedAttestationCount())
+	require.NoError(t, service.saveOrphanedOperations(ctx, r2, r4))
+	require.Equal(t, 1, service.cfg.AttPool.AggregatedAttestationCount())
+	pending, err := service.cfg.BLSToExecPool.PendingBLSToExecChanges()
+	require.NoError(t, err)
+	require.Equal(t, 15, len(pending))
 }

 func TestSaveOrphanedAtts_DoublyLinkedTrie(t *testing.T) {
@@ -404,7 +441,7 @@ func TestSaveOrphanedAtts_DoublyLinkedTrie(t *testing.T) {
 		util.SaveBlock(t, ctx, beaconDB, blk)
 	}

-	require.NoError(t, service.saveOrphanedAtts(ctx, r3, r4))
+	require.NoError(t, service.saveOrphanedOperations(ctx, r3, r4))
 	require.Equal(t, 3, service.cfg.AttPool.AggregatedAttestationCount())
 	wantAtts := []*ethpb.Attestation{
 		blk3.Block.Body.Attestations[0],
@@ -468,7 +505,7 @@ func TestSaveOrphanedAtts_CanFilter_DoublyLinkedTrie(t *testing.T) {
 		util.SaveBlock(t, ctx, beaconDB, blk)
 	}

-	require.NoError(t, service.saveOrphanedAtts(ctx, r2, r4))
+	require.NoError(t, service.saveOrphanedOperations(ctx, r2, r4))
 	require.Equal(t, 0, service.cfg.AttPool.AggregatedAttestationCount())
 }

@@ -509,7 +546,9 @@ func TestUpdateHead_noSavedChanges(t *testing.T) {
 	st, blkRoot, err = prepareForkchoiceState(ctx, 0, bellatrixBlkRoot, [32]byte{}, [32]byte{}, fcp, fcp)
 	require.NoError(t, err)
 	require.NoError(t, fcs.InsertNode(ctx, st, blkRoot))
-	newRoot, err := service.cfg.ForkChoiceStore.Head(ctx, []uint64{1, 2})
+	fcs.SetBalancesByRooter(func(context.Context, [32]byte) ([]uint64, error) { return []uint64{1, 2}, nil })
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{}))
+	newRoot, err := service.cfg.ForkChoiceStore.Head(ctx)
 	require.NoError(t, err)
 	require.NotEqual(t, headRoot, newRoot)
 	require.Equal(t, headRoot, service.headRoot())
--- a/beacon-chain/blockchain/init_sync_process_block.go
+++ b/beacon-chain/blockchain/init_sync_process_block.go
@@ -10,7 +10,7 @@ import (

 // This saves a beacon block to the initial sync blocks cache. It rate limits how many blocks
 // the cache keeps in memory (2 epochs worth of blocks) and saves them to DB when it hits this limit.
-func (s *Service) saveInitSyncBlock(ctx context.Context, r [32]byte, b interfaces.SignedBeaconBlock) error {
+func (s *Service) saveInitSyncBlock(ctx context.Context, r [32]byte, b interfaces.ReadOnlySignedBeaconBlock) error {
 	s.initSyncBlocksLock.Lock()
 	s.initSyncBlocks[r] = b
 	numBlocks := len(s.initSyncBlocks)
@@ -43,7 +43,7 @@ func (s *Service) hasBlockInInitSyncOrDB(ctx context.Context, r [32]byte) bool {

 // Returns block for a given root `r` from either the initial sync blocks cache or the DB.
 // Error is returned if the block is not found in either cache or DB.
-func (s *Service) getBlock(ctx context.Context, r [32]byte) (interfaces.SignedBeaconBlock, error) {
+func (s *Service) getBlock(ctx context.Context, r [32]byte) (interfaces.ReadOnlySignedBeaconBlock, error) {
 	s.initSyncBlocksLock.RLock()

 	// Check cache first because it's faster.
@@ -64,11 +64,11 @@ func (s *Service) getBlock(ctx context.Context, r [32]byte) (interfaces.SignedBe

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

-	blks := make([]interfaces.SignedBeaconBlock, 0, len(s.initSyncBlocks))
+	blks := make([]interfaces.ReadOnlySignedBeaconBlock, 0, len(s.initSyncBlocks))
 	for _, b := range s.initSyncBlocks {
 		blks = append(blks, b)
 	}
@@ -79,5 +79,5 @@ func (s *Service) getInitSyncBlocks() []interfaces.SignedBeaconBlock {
 func (s *Service) clearInitSyncBlocks() {
 	s.initSyncBlocksLock.Lock()
 	defer s.initSyncBlocksLock.Unlock()
-	s.initSyncBlocks = make(map[[32]byte]interfaces.SignedBeaconBlock)
+	s.initSyncBlocks = make(map[[32]byte]interfaces.ReadOnlySignedBeaconBlock)
 }
--- a/beacon-chain/blockchain/log.go
+++ b/beacon-chain/blockchain/log.go
@@ -21,7 +21,7 @@ import (
 var log = logrus.WithField("prefix", "blockchain")

 // logs state transition related data every slot.
-func logStateTransitionData(b interfaces.BeaconBlock) error {
+func logStateTransitionData(b interfaces.ReadOnlyBeaconBlock) error {
 	log := log.WithField("slot", b.Slot())
 	if len(b.Body().Attestations()) > 0 {
 		log = log.WithField("attestations", len(b.Body().Attestations()))
@@ -38,14 +38,14 @@ func logStateTransitionData(b interfaces.BeaconBlock) error {
 	if len(b.Body().VoluntaryExits()) > 0 {
 		log = log.WithField("voluntaryExits", len(b.Body().VoluntaryExits()))
 	}
-	if b.Version() == version.Altair || b.Version() == version.Bellatrix {
+	if b.Version() >= version.Altair {
 		agg, err := b.Body().SyncAggregate()
 		if err != nil {
 			return err
 		}
 		log = log.WithField("syncBitsCount", agg.SyncCommitteeBits.Count())
 	}
-	if b.Version() == version.Bellatrix {
+	if b.Version() >= version.Bellatrix {
 		p, err := b.Body().Execution()
 		if err != nil {
 			return err
@@ -66,7 +66,7 @@ func logStateTransitionData(b interfaces.BeaconBlock) error {
 	return nil
 }

-func logBlockSyncStatus(block interfaces.BeaconBlock, blockRoot [32]byte, justified, finalized *ethpb.Checkpoint, receivedTime time.Time, genesisTime uint64) error {
+func logBlockSyncStatus(block interfaces.ReadOnlyBeaconBlock, blockRoot [32]byte, justified, finalized *ethpb.Checkpoint, receivedTime time.Time, genesisTime uint64) error {
 	startTime, err := slots.ToTime(genesisTime, block.Slot())
 	if err != nil {
 		return err
@@ -87,6 +87,7 @@ func logBlockSyncStatus(block interfaces.BeaconBlock, blockRoot [32]byte, justif
 			"version":                   version.String(block.Version()),
 			"sinceSlotStartTime":        prysmTime.Now().Sub(startTime),
 			"chainServiceProcessedTime": prysmTime.Now().Sub(receivedTime),
+			"deposits":                  len(block.Body().Deposits()),
 		}).Debug("Synced new block")
 	} else {
 		log.WithFields(logrus.Fields{
@@ -101,7 +102,7 @@ func logBlockSyncStatus(block interfaces.BeaconBlock, blockRoot [32]byte, justif
 }

 // logs payload related data every slot.
-func logPayload(block interfaces.BeaconBlock) error {
+func logPayload(block interfaces.ReadOnlyBeaconBlock) error {
 	isExecutionBlk, err := blocks.IsExecutionBlock(block.Body())
 	if err != nil {
 		return errors.Wrap(err, "could not determine if block is execution block")
@@ -117,12 +118,24 @@ func logPayload(block interfaces.BeaconBlock) error {
 		return errors.New("gas limit should not be 0")
 	}
 	gasUtilized := float64(payload.GasUsed()) / float64(payload.GasLimit())
-
-	log.WithFields(logrus.Fields{
+	fields := logrus.Fields{
 		"blockHash":   fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash())),
 		"parentHash":  fmt.Sprintf("%#x", bytesutil.Trunc(payload.ParentHash())),
 		"blockNumber": payload.BlockNumber,
 		"gasUtilized": fmt.Sprintf("%.2f", gasUtilized),
-	}).Debug("Synced new payload")
+	}
+	if block.Version() >= version.Capella {
+		withdrawals, err := payload.Withdrawals()
+		if err != nil {
+			return errors.Wrap(err, "could not get withdrawals")
+		}
+		fields["withdrawals"] = len(withdrawals)
+		changes, err := block.Body().BLSToExecutionChanges()
+		if err != nil {
+			return errors.Wrap(err, "could not get BLSToExecutionChanges")
+		}
+		fields["blsToExecutionChanges"] = len(changes)
+	}
+	log.WithFields(fields).Debug("Synced new payload")
 	return nil
 }
--- a/beacon-chain/blockchain/log_test.go
+++ b/beacon-chain/blockchain/log_test.go
@@ -25,11 +25,11 @@ func Test_logStateTransitionData(t *testing.T) {
 	require.NoError(t, err)
 	tests := []struct {
 		name string
-		b    func() interfaces.BeaconBlock
+		b    func() interfaces.ReadOnlyBeaconBlock
 		want string
 	}{
 		{name: "empty block body",
-			b: func() interfaces.BeaconBlock {
+			b: func() interfaces.ReadOnlyBeaconBlock {
 				wb, err := blocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}})
 				require.NoError(t, err)
 				return wb
@@ -37,7 +37,7 @@ func Test_logStateTransitionData(t *testing.T) {
 			want: "\"Finished applying state transition\" prefix=blockchain slot=0",
 		},
 		{name: "has attestation",
-			b: func() interfaces.BeaconBlock {
+			b: func() interfaces.ReadOnlyBeaconBlock {
 				wb, err := blocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{Attestations: []*ethpb.Attestation{{}}}})
 				require.NoError(t, err)
 				return wb
@@ -45,7 +45,7 @@ func Test_logStateTransitionData(t *testing.T) {
 			want: "\"Finished applying state transition\" attestations=1 prefix=blockchain slot=0",
 		},
 		{name: "has deposit",
-			b: func() interfaces.BeaconBlock {
+			b: func() interfaces.ReadOnlyBeaconBlock {
 				wb, err := blocks.NewBeaconBlock(
 					&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
 						Attestations: []*ethpb.Attestation{{}},
@@ -56,7 +56,7 @@ func Test_logStateTransitionData(t *testing.T) {
 			want: "\"Finished applying state transition\" attestations=1 deposits=1 prefix=blockchain slot=0",
 		},
 		{name: "has attester slashing",
-			b: func() interfaces.BeaconBlock {
+			b: func() interfaces.ReadOnlyBeaconBlock {
 				wb, err := blocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
 					AttesterSlashings: []*ethpb.AttesterSlashing{{}}}})
 				require.NoError(t, err)
@@ -65,7 +65,7 @@ func Test_logStateTransitionData(t *testing.T) {
 			want: "\"Finished applying state transition\" attesterSlashings=1 prefix=blockchain slot=0",
 		},
 		{name: "has proposer slashing",
-			b: func() interfaces.BeaconBlock {
+			b: func() interfaces.ReadOnlyBeaconBlock {
 				wb, err := blocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
 					ProposerSlashings: []*ethpb.ProposerSlashing{{}}}})
 				require.NoError(t, err)
@@ -74,7 +74,7 @@ func Test_logStateTransitionData(t *testing.T) {
 			want: "\"Finished applying state transition\" prefix=blockchain proposerSlashings=1 slot=0",
 		},
 		{name: "has exit",
-			b: func() interfaces.BeaconBlock {
+			b: func() interfaces.ReadOnlyBeaconBlock {
 				wb, err := blocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
 					VoluntaryExits: []*ethpb.SignedVoluntaryExit{{}}}})
 				require.NoError(t, err)
@@ -83,7 +83,7 @@ func Test_logStateTransitionData(t *testing.T) {
 			want: "\"Finished applying state transition\" prefix=blockchain slot=0 voluntaryExits=1",
 		},
 		{name: "has everything",
-			b: func() interfaces.BeaconBlock {
+			b: func() interfaces.ReadOnlyBeaconBlock {
 				wb, err := blocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
 					Attestations:      []*ethpb.Attestation{{}},
 					Deposits:          []*ethpb.Deposit{{}},
@@ -96,7 +96,7 @@ func Test_logStateTransitionData(t *testing.T) {
 			want: "\"Finished applying state transition\" attestations=1 attesterSlashings=1 deposits=1 prefix=blockchain proposerSlashings=1 slot=0 voluntaryExits=1",
 		},
 		{name: "has payload",
-			b:    func() interfaces.BeaconBlock { return wrappedPayloadBlk },
+			b:    func() interfaces.ReadOnlyBeaconBlock { return wrappedPayloadBlk },
 			want: "\"Finished applying state transition\" payloadHash=0x010203 prefix=blockchain slot=0 syncBitsCount=0 txCount=2",
 		},
 	}
--- a/beacon-chain/blockchain/metrics.go
+++ b/beacon-chain/blockchain/metrics.go
@@ -11,7 +11,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/runtime/version"
@@ -130,14 +130,6 @@ var (
 		Name: "sync_head_state_hit",
 		Help: "The number of sync head state requests that are present in the cache.",
 	})
-	stateBalanceCacheHit = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "state_balance_cache_hit",
-		Help: "Count the number of state balance cache hits.",
-	})
-	stateBalanceCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "state_balance_cache_miss",
-		Help: "Count the number of state balance cache hits.",
-	})
 	newPayloadValidNodeCount = promauto.NewCounter(prometheus.CounterOpts{
 		Name: "new_payload_valid_node_count",
 		Help: "Count the number of valid nodes after newPayload EE call",
@@ -216,7 +208,7 @@ var (
 )

 // reportSlotMetrics reports slot related metrics.
-func reportSlotMetrics(stateSlot, headSlot, clockSlot types.Slot, finalizedCheckpoint *ethpb.Checkpoint) {
+func reportSlotMetrics(stateSlot, headSlot, clockSlot primitives.Slot, finalizedCheckpoint *ethpb.Checkpoint) {
 	clockTimeSlot.Set(float64(clockSlot))
 	beaconSlot.Set(float64(stateSlot))
 	beaconHeadSlot.Set(float64(headSlot))
@@ -228,7 +220,7 @@ func reportSlotMetrics(stateSlot, headSlot, clockSlot types.Slot, finalizedCheck

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

 	// Validator instances
 	pendingInstances := 0
@@ -247,7 +239,7 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	slashingEffectiveBalance := uint64(0)

 	for i, validator := range postState.Validators() {
-		bal, err := postState.BalanceAtIndex(types.ValidatorIndex(i))
+		bal, err := postState.BalanceAtIndex(primitives.ValidatorIndex(i))
 		if err != nil {
 			log.WithError(err).Error("Could not load validator balance")
 			continue
@@ -317,9 +309,8 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	var b *precompute.Balance
 	var v []*precompute.Validator
 	var err error
-	switch headState.Version() {
-	case version.Phase0:
-		// Validator participation should be viewed on the canonical chain.
+
+	if headState.Version() == version.Phase0 {
 		v, b, err = precompute.New(ctx, headState)
 		if err != nil {
 			return err
@@ -328,7 +319,7 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 		if err != nil {
 			return err
 		}
-	case version.Altair, version.Bellatrix:
+	} else if headState.Version() >= version.Altair {
 		v, b, err = altair.InitializePrecomputeValidators(ctx, headState)
 		if err != nil {
 			return err
@@ -337,9 +328,10 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 		if err != nil {
 			return err
 		}
-	default:
+	} else {
 		return errors.Errorf("invalid state type provided: %T", headState.ToProtoUnsafe())
 	}
+
 	prevEpochActiveBalances.Set(float64(b.ActivePrevEpoch))
 	prevEpochSourceBalances.Set(float64(b.PrevEpochAttested))
 	prevEpochTargetBalances.Set(float64(b.PrevEpochTargetAttested))
@@ -353,7 +345,7 @@ func reportEpochMetrics(ctx context.Context, postState, headState state.BeaconSt
 	return nil
 }

-func reportAttestationInclusion(blk interfaces.BeaconBlock) {
+func reportAttestationInclusion(blk interfaces.ReadOnlyBeaconBlock) {
 	for _, att := range blk.Body().Attestations() {
 		attestationInclusionDelay.Observe(float64(blk.Slot() - att.Data.Slot))
 	}
--- a/beacon-chain/blockchain/mock_test.go
+++ b/beacon-chain/blockchain/mock_test.go
@@ -1,13 +1,10 @@
 package blockchain

 import (
-	"context"
-	"errors"
 	"testing"

 	testDB "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 )

@@ -25,26 +22,5 @@ func testServiceOptsWithDB(t *testing.T) []Option {
 // in your code path. this is a lightweight way to satisfy the stategen/beacondb
 // initialization requirements w/o the overhead of db init.
 func testServiceOptsNoDB() []Option {
-	return []Option{
-		withStateBalanceCache(satisfactoryStateBalanceCache()),
-	}
-}
-
-type mockStateByRooter struct {
-	state state.BeaconState
-	err   error
-}
-
-var _ stateByRooter = &mockStateByRooter{}
-
-func (m mockStateByRooter) StateByRoot(_ context.Context, _ [32]byte) (state.BeaconState, error) {
-	return m.state, m.err
-}
-
-// returns an instance of the state balance cache that can be used
-// to satisfy the requirement for one in NewService, but which will
-// always return an error if used.
-func satisfactoryStateBalanceCache() *stateBalanceCache {
-	err := errors.New("satisfactoryStateBalanceCache doesn't perform real caching")
-	return &stateBalanceCache{stateGen: mockStateByRooter{err: err}}
+	return []Option{}
 }
--- a/beacon-chain/blockchain/options.go
+++ b/beacon-chain/blockchain/options.go
@@ -9,6 +9,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/execution"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/attestations"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/blstoexec"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/slashings"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/p2p"
@@ -99,6 +100,14 @@ func WithSlashingPool(p slashings.PoolManager) Option {
 	}
 }

+// WithBLSToExecPool to keep track of BLS to Execution address changes.
+func WithBLSToExecPool(p blstoexec.PoolManager) Option {
+	return func(s *Service) error {
+		s.cfg.BLSToExecPool = p
+		return nil
+	}
+}
+
 // WithP2PBroadcaster to broadcast messages after appropriate processing.
 func WithP2PBroadcaster(p p2p.Broadcaster) Option {
 	return func(s *Service) error {
@@ -147,13 +156,6 @@ func WithSlasherAttestationsFeed(f *event.Feed) Option {
 	}
 }

-func withStateBalanceCache(c *stateBalanceCache) Option {
-	return func(s *Service) error {
-		s.justifiedBalances = c
-		return nil
-	}
-}
-
 // WithFinalizedStateAtStartUp to store finalized state at start up.
 func WithFinalizedStateAtStartUp(st state.BeaconState) Option {
 	return func(s *Service) error {
--- a/beacon-chain/blockchain/pow_block.go
+++ b/beacon-chain/blockchain/pow_block.go
@@ -13,30 +13,32 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v3/runtime/version"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 	"github.com/sirupsen/logrus"
 )

 // validateMergeBlock validates terminal block hash in the event of manual overrides before checking for total difficulty.
 //
-// def validate_merge_block(block: BeaconBlock) -> None:
-//    if TERMINAL_BLOCK_HASH != Hash32():
-//        # If `TERMINAL_BLOCK_HASH` is used as an override, the activation epoch must be reached.
-//        assert compute_epoch_at_slot(block.slot) >= TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
-//        assert block.body.execution_payload.parent_hash == TERMINAL_BLOCK_HASH
-//        return
+// def validate_merge_block(block: ReadOnlyBeaconBlock) -> None:
 //
-//    pow_block = get_pow_block(block.body.execution_payload.parent_hash)
-//    # Check if `pow_block` is available
-//    assert pow_block is not None
-//    pow_parent = get_pow_block(pow_block.parent_hash)
-//    # Check if `pow_parent` is available
-//    assert pow_parent is not None
-//    # Check if `pow_block` is a valid terminal PoW block
-//    assert is_valid_terminal_pow_block(pow_block, pow_parent)
-func (s *Service) validateMergeBlock(ctx context.Context, b interfaces.SignedBeaconBlock) error {
+//	if TERMINAL_BLOCK_HASH != Hash32():
+//	    # If `TERMINAL_BLOCK_HASH` is used as an override, the activation epoch must be reached.
+//	    assert compute_epoch_at_slot(block.slot) >= TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
+//	    assert block.body.execution_payload.parent_hash == TERMINAL_BLOCK_HASH
+//	    return
+//
+//	pow_block = get_pow_block(block.body.execution_payload.parent_hash)
+//	# Check if `pow_block` is available
+//	assert pow_block is not None
+//	pow_parent = get_pow_block(pow_block.parent_hash)
+//	# Check if `pow_parent` is available
+//	assert pow_parent is not None
+//	# Check if `pow_block` is a valid terminal PoW block
+//	assert is_valid_terminal_pow_block(pow_block, pow_parent)
+func (s *Service) validateMergeBlock(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock) error {
 	if err := blocks.BeaconBlockIsNil(b); err != nil {
 		return err
 	}
@@ -47,9 +49,13 @@ func (s *Service) validateMergeBlock(ctx context.Context, b interfaces.SignedBea
 	if payload.IsNil() {
 		return errors.New("nil execution payload")
 	}
-	if err := validateTerminalBlockHash(b.Block().Slot(), payload); err != nil {
+	ok, err := canUseValidatedTerminalBlockHash(b.Block().Slot(), payload)
+	if err != nil {
 		return errors.Wrap(err, "could not validate terminal block hash")
 	}
+	if ok {
+		return nil
+	}
 	mergeBlockParentHash, mergeBlockTD, err := s.getBlkParentHashAndTD(ctx, payload.ParentHash())
 	if err != nil {
 		return errors.Wrap(err, "could not get merge block parent hash and total difficulty")
@@ -91,6 +97,7 @@ func (s *Service) getBlkParentHashAndTD(ctx context.Context, blkHash []byte) ([]
 	if blk == nil {
 		return nil, nil, errors.New("pow block is nil")
 	}
+	blk.Version = version.Bellatrix
 	blkTDBig, err := hexutil.DecodeBig(blk.TotalDifficulty)
 	if err != nil {
 		return nil, nil, errors.Wrap(err, "could not decode merge block total difficulty")
@@ -102,32 +109,34 @@ func (s *Service) getBlkParentHashAndTD(ctx context.Context, blkHash []byte) ([]
 	return blk.ParentHash[:], blkTDUint256, nil
 }

-// validateTerminalBlockHash validates if the merge block is a valid terminal PoW block.
+// canUseValidatedTerminalBlockHash validates if the merge block is a valid terminal PoW block.
 // spec code:
 // if TERMINAL_BLOCK_HASH != Hash32():
-//        # If `TERMINAL_BLOCK_HASH` is used as an override, the activation epoch must be reached.
-//        assert compute_epoch_at_slot(block.slot) >= TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
-//        assert block.body.execution_payload.parent_hash == TERMINAL_BLOCK_HASH
-//        return
-func validateTerminalBlockHash(blkSlot types.Slot, payload interfaces.ExecutionData) error {
+//
+//	# If `TERMINAL_BLOCK_HASH` is used as an override, the activation epoch must be reached.
+//	assert compute_epoch_at_slot(block.slot) >= TERMINAL_BLOCK_HASH_ACTIVATION_EPOCH
+//	assert block.body.execution_payload.parent_hash == TERMINAL_BLOCK_HASH
+//	return
+func canUseValidatedTerminalBlockHash(blkSlot primitives.Slot, payload interfaces.ExecutionData) (bool, error) {
 	if bytesutil.ToBytes32(params.BeaconConfig().TerminalBlockHash.Bytes()) == [32]byte{} {
-		return nil
+		return false, nil
 	}
 	if params.BeaconConfig().TerminalBlockHashActivationEpoch > slots.ToEpoch(blkSlot) {
-		return errors.New("terminal block hash activation epoch not reached")
+		return false, errors.New("terminal block hash activation epoch not reached")
 	}
 	if !bytes.Equal(payload.ParentHash(), params.BeaconConfig().TerminalBlockHash.Bytes()) {
-		return errors.New("parent hash does not match terminal block hash")
+		return false, errors.New("parent hash does not match terminal block hash")
 	}
-	return nil
+	return true, nil
 }

 // validateTerminalBlockDifficulties validates terminal pow block by comparing own total difficulty with parent's total difficulty.
 //
 // def is_valid_terminal_pow_block(block: PowBlock, parent: PowBlock) -> bool:
-//    is_total_difficulty_reached = block.total_difficulty >= TERMINAL_TOTAL_DIFFICULTY
-//    is_parent_total_difficulty_valid = parent.total_difficulty < TERMINAL_TOTAL_DIFFICULTY
-//    return is_total_difficulty_reached and is_parent_total_difficulty_valid
+//
+//	is_total_difficulty_reached = block.total_difficulty >= TERMINAL_TOTAL_DIFFICULTY
+//	is_parent_total_difficulty_valid = parent.total_difficulty < TERMINAL_TOTAL_DIFFICULTY
+//	return is_total_difficulty_reached and is_parent_total_difficulty_valid
 func validateTerminalBlockDifficulties(currentDifficulty *uint256.Int, parentDifficulty *uint256.Int) (bool, error) {
 	b, ok := new(big.Int).SetString(params.BeaconConfig().TerminalTotalDifficulty, 10)
 	if !ok {
--- a/beacon-chain/blockchain/pow_block_test.go
+++ b/beacon-chain/blockchain/pow_block_test.go
@@ -18,6 +18,7 @@ import (
 	enginev1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
+	"github.com/prysmaticlabs/prysm/v3/testing/util"
 )

 func Test_validTerminalPowBlock(t *testing.T) {
@@ -213,20 +214,42 @@ func Test_getBlkParentHashAndTD(t *testing.T) {
 func Test_validateTerminalBlockHash(t *testing.T) {
 	wrapped, err := blocks.WrappedExecutionPayload(&enginev1.ExecutionPayload{})
 	require.NoError(t, err)
-	require.NoError(t, validateTerminalBlockHash(1, wrapped))
+	ok, err := canUseValidatedTerminalBlockHash(1, wrapped)
+	require.NoError(t, err)
+	require.Equal(t, false, ok)

 	cfg := params.BeaconConfig()
 	cfg.TerminalBlockHash = [32]byte{0x01}
 	params.OverrideBeaconConfig(cfg)
-	require.ErrorContains(t, "terminal block hash activation epoch not reached", validateTerminalBlockHash(1, wrapped))
+	ok, err = canUseValidatedTerminalBlockHash(1, wrapped)
+	require.ErrorContains(t, "terminal block hash activation epoch not reached", err)
+	require.Equal(t, false, ok)

 	cfg.TerminalBlockHashActivationEpoch = 0
 	params.OverrideBeaconConfig(cfg)
-	require.ErrorContains(t, "parent hash does not match terminal block hash", validateTerminalBlockHash(1, wrapped))
+	ok, err = canUseValidatedTerminalBlockHash(1, wrapped)
+	require.ErrorContains(t, "parent hash does not match terminal block hash", err)
+	require.Equal(t, false, ok)

 	wrapped, err = blocks.WrappedExecutionPayload(&enginev1.ExecutionPayload{
 		ParentHash: cfg.TerminalBlockHash.Bytes(),
 	})
 	require.NoError(t, err)
-	require.NoError(t, validateTerminalBlockHash(1, wrapped))
+	ok, err = canUseValidatedTerminalBlockHash(1, wrapped)
+	require.NoError(t, err)
+	require.Equal(t, true, ok)
+
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB, doublylinkedtree.New())),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	blk, err := blocks.NewSignedBeaconBlock(util.HydrateSignedBeaconBlockBellatrix(&ethpb.SignedBeaconBlockBellatrix{}))
+	require.NoError(t, err)
+	blk.SetSlot(1)
+	require.NoError(t, blk.SetExecution(wrapped))
+	require.NoError(t, service.validateMergeBlock(ctx, blk))
 }
--- a/beacon-chain/blockchain/process_attestation.go
+++ b/beacon-chain/blockchain/process_attestation.go
@@ -6,7 +6,6 @@ import (

 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1/attestation"
@@ -19,24 +18,25 @@ import (
 // The delay is handled by the caller in `processAttestations`.
 //
 // Spec pseudocode definition:
-//   def on_attestation(store: Store, attestation: Attestation) -> None:
-//    """
-//    Run ``on_attestation`` upon receiving a new ``attestation`` from either within a block or directly on the wire.
 //
-//    An ``attestation`` that is asserted as invalid may be valid at a later time,
-//    consider scheduling it for later processing in such case.
-//    """
-//    validate_on_attestation(store, attestation)
-//    store_target_checkpoint_state(store, attestation.data.target)
+//	def on_attestation(store: Store, attestation: Attestation) -> None:
+//	 """
+//	 Run ``on_attestation`` upon receiving a new ``attestation`` from either within a block or directly on the wire.
 //
-//    # Get state at the `target` to fully validate attestation
-//    target_state = store.checkpoint_states[attestation.data.target]
-//    indexed_attestation = get_indexed_attestation(target_state, attestation)
-//    assert is_valid_indexed_attestation(target_state, indexed_attestation)
+//	 An ``attestation`` that is asserted as invalid may be valid at a later time,
+//	 consider scheduling it for later processing in such case.
+//	 """
+//	 validate_on_attestation(store, attestation)
+//	 store_target_checkpoint_state(store, attestation.data.target)
 //
-//    # Update latest messages for attesting indices
-//    update_latest_messages(store, indexed_attestation.attesting_indices, attestation)
-func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation) error {
+//	 # Get state at the `target` to fully validate attestation
+//	 target_state = store.checkpoint_states[attestation.data.target]
+//	 indexed_attestation = get_indexed_attestation(target_state, attestation)
+//	 assert is_valid_indexed_attestation(target_state, indexed_attestation)
+//
+//	 # Update latest messages for attesting indices
+//	 update_latest_messages(store, indexed_attestation.attesting_indices, attestation)
+func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation, disparity time.Duration) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onAttestation")
 	defer span.End()

@@ -62,7 +62,7 @@ func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation) error
 	genesisTime := uint64(s.genesisTime.Unix())

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

@@ -71,11 +71,11 @@ func (s *Service) OnAttestation(ctx context.Context, a *ethpb.Attestation) error
 		return errors.Wrap(err, "could not verify attestation beacon block")
 	}

-	// Note that LMG GHOST and FFG consistency check is ignored because it was performed in sync's validation pipeline:
+	// Note that LMD GHOST and FFG consistency check is ignored because it was performed in sync's validation pipeline:
 	// validate_aggregate_proof.go and validate_beacon_attestation.go

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

--- a/beacon-chain/blockchain/process_attestation_helpers.go
+++ b/beacon-chain/blockchain/process_attestation_helpers.go
@@ -11,7 +11,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
@@ -60,9 +60,9 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (stat

 // verifyAttTargetEpoch validates attestation is from the current or previous epoch.
 func verifyAttTargetEpoch(_ context.Context, genesisTime, nowTime uint64, c *ethpb.Checkpoint) error {
-	currentSlot := types.Slot((nowTime - genesisTime) / params.BeaconConfig().SecondsPerSlot)
+	currentSlot := primitives.Slot((nowTime - genesisTime) / params.BeaconConfig().SecondsPerSlot)
 	currentEpoch := slots.ToEpoch(currentSlot)
-	var prevEpoch types.Epoch
+	var prevEpoch primitives.Epoch
 	// Prevents previous epoch under flow
 	if currentEpoch > 1 {
 		prevEpoch = currentEpoch - 1
--- a/beacon-chain/blockchain/process_attestation_test.go
+++ b/beacon-chain/blockchain/process_attestation_test.go
@@ -8,11 +8,10 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/transition"
 	testDB "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
-	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/assert"
@@ -118,7 +117,7 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {

 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			err := service.OnAttestation(ctx, tt.a)
+			err := service.OnAttestation(ctx, tt.a, 0)
 			if tt.wantedErr != "" {
 				assert.ErrorContains(t, tt.wantedErr, err)
 			} else {
@@ -155,7 +154,7 @@ func TestStore_OnAttestation_Ok_DoublyLinkedTree(t *testing.T) {
 	state, blkRoot, err := prepareForkchoiceState(ctx, 0, tRoot, tRoot, params.BeaconConfig().ZeroHash, ojc, ofc)
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
-	require.NoError(t, service.OnAttestation(ctx, att[0]))
+	require.NoError(t, service.OnAttestation(ctx, att[0], 0))
 }

 func TestStore_SaveCheckpointState(t *testing.T) {
@@ -231,7 +230,7 @@ func TestStore_UpdateCheckpointState(t *testing.T) {
 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)

-	epoch := types.Epoch(1)
+	epoch := primitives.Epoch(1)
 	baseState, _ := util.DeterministicGenesisState(t, 1)
 	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("hi"), fieldparams.RootLength)}
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)))
@@ -324,94 +323,3 @@ func TestVerifyBeaconBlock_OK(t *testing.T) {

 	assert.NoError(t, service.verifyBeaconBlock(ctx, d), "Did not receive the wanted error")
 }
-
-func TestVerifyFinalizedConsistency_InconsistentRoot_DoublyLinkedTree(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	b32 := util.NewBeaconBlock()
-	b32.Block.Slot = 32
-	util.SaveBlock(t, ctx, service.cfg.BeaconDB, b32)
-	r32, err := b32.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	require.NoError(t, service.ForkChoicer().UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: 1}))
-	b33 := util.NewBeaconBlock()
-	b33.Block.Slot = 33
-	b33.Block.ParentRoot = r32[:]
-	util.SaveBlock(t, ctx, service.cfg.BeaconDB, b33)
-	r33, err := b33.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
-	require.ErrorContains(t, "Root and finalized store are not consistent", err)
-}
-
-func TestVerifyFinalizedConsistency_OK(t *testing.T) {
-	ctx := context.Background()
-
-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	b32 := util.NewBeaconBlock()
-	b32.Block.Slot = 32
-	util.SaveBlock(t, ctx, service.cfg.BeaconDB, b32)
-	r32, err := b32.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	require.NoError(t, service.ForkChoicer().UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: 1, Root: r32}))
-	b33 := util.NewBeaconBlock()
-	b33.Block.Slot = 33
-	b33.Block.ParentRoot = r32[:]
-	util.SaveBlock(t, ctx, service.cfg.BeaconDB, b33)
-	r33, err := b33.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
-	require.NoError(t, err)
-}
-
-func TestVerifyFinalizedConsistency_IsCanonical(t *testing.T) {
-	ctx := context.Background()
-
-	opts := testServiceOptsWithDB(t)
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-
-	b32 := util.NewBeaconBlock()
-	b32.Block.Slot = 32
-	r32, err := b32.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	b33 := util.NewBeaconBlock()
-	b33.Block.Slot = 33
-	b33.Block.ParentRoot = r32[:]
-	r33, err := b33.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	ojc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
-	ofc := &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
-	state, blkRoot, err := prepareForkchoiceState(ctx, b32.Block.Slot, r32, [32]byte{}, params.BeaconConfig().ZeroHash, ojc, ofc)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
-	state, blkRoot, err = prepareForkchoiceState(ctx, b33.Block.Slot, r33, r32, params.BeaconConfig().ZeroHash, ojc, ofc)
-	require.NoError(t, err)
-	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
-
-	jc := &forkchoicetypes.Checkpoint{Epoch: 0, Root: r32}
-	require.NoError(t, service.cfg.ForkChoiceStore.UpdateJustifiedCheckpoint(jc))
-	_, err = service.cfg.ForkChoiceStore.Head(ctx, []uint64{})
-	require.NoError(t, err)
-	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
-	require.NoError(t, err)
-}
--- a/beacon-chain/blockchain/process_block.go
+++ b/beacon-chain/blockchain/process_block.go
@@ -19,7 +19,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v3/monitoring/tracing"
@@ -28,6 +28,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1/attestation"
 	"github.com/prysmaticlabs/prysm/v3/runtime/version"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
+	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

@@ -45,53 +46,54 @@ var initialSyncBlockCacheSize = uint64(2 * params.BeaconConfig().SlotsPerEpoch)
 // computation in this method and methods it calls into.
 //
 // Spec pseudocode definition:
-//   def on_block(store: Store, signed_block: SignedBeaconBlock) -> 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
+//	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 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
+//	 # 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
 //
-//    # 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
+//	 # 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 finalized checkpoint
-//    if state.finalized_checkpoint.epoch > store.finalized_checkpoint.epoch:
-//        store.finalized_checkpoint = state.finalized_checkpoint
+//	 # 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
 //
-//        # 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 finalized checkpoint
+//	 if state.finalized_checkpoint.epoch > store.finalized_checkpoint.epoch:
+//	     store.finalized_checkpoint = state.finalized_checkpoint
 //
-//            # 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.SignedBeaconBlock, blockRoot [32]byte) error {
+//	     # 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 {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlock")
 	defer span.End()
 	if err := consensusblocks.BeaconBlockIsNil(signed); err != nil {
@@ -105,6 +107,11 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.SignedBeaconBlo
 		return err
 	}

+	// Verify that the parent block is in forkchoice
+	if !s.ForkChoicer().HasNode(b.ParentRoot()) {
+		return ErrNotDescendantOfFinalized
+	}
+
 	// Save current justified and finalized epochs for future use.
 	currStoreJustifiedEpoch := s.ForkChoicer().JustifiedCheckpoint().Epoch
 	currStoreFinalizedEpoch := s.ForkChoicer().FinalizedCheckpoint().Epoch
@@ -145,6 +152,10 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.SignedBeaconBlo
 	if err := s.handleBlockAttestations(ctx, signed.Block(), postState); err != nil {
 		return errors.Wrap(err, "could not handle block's attestations")
 	}
+	if err := s.handleBlockBLSToExecChanges(signed.Block()); err != nil {
+		return errors.Wrap(err, "could not handle block's BLSToExecutionChanges")
+	}
+
 	s.InsertSlashingsToForkChoiceStore(ctx, signed.Block().Body().AttesterSlashings())
 	if isValidPayload {
 		if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, blockRoot); err != nil {
@@ -180,24 +191,30 @@ func (s *Service) onBlock(ctx context.Context, signed interfaces.SignedBeaconBlo
 	}

 	justified := s.ForkChoicer().JustifiedCheckpoint()
-	balances, err := s.justifiedBalances.get(ctx, justified.Root)
-	if err != nil {
-		msg := fmt.Sprintf("could not read balances for state w/ justified checkpoint %#x", justified.Root)
-		return errors.Wrap(err, msg)
-	}
-
 	start := time.Now()
-	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx, balances)
+	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx)
 	if err != nil {
 		log.WithError(err).Warn("Could not update head")
 	}
+	if blockRoot != headRoot {
+		receivedWeight, err := s.ForkChoicer().Weight(blockRoot)
+		if err != nil {
+			log.WithField("root", fmt.Sprintf("%#x", blockRoot)).Warn("could not determine node weight")
+		}
+		headWeight, err := s.ForkChoicer().Weight(headRoot)
+		if err != nil {
+			log.WithField("root", fmt.Sprintf("%#x", headRoot)).Warn("could not determine node weight")
+		}
+		log.WithFields(logrus.Fields{
+			"receivedRoot":   fmt.Sprintf("%#x", blockRoot),
+			"receivedWeight": receivedWeight,
+			"headRoot":       fmt.Sprintf("%#x", headRoot),
+			"headWeight":     headWeight,
+		}).Debug("Head block is not the received block")
+	}
 	newBlockHeadElapsedTime.Observe(float64(time.Since(start).Milliseconds()))

-	if err := s.notifyEngineIfChangedHead(ctx, headRoot); err != nil {
-		return err
-	}
-
-	if err := s.pruneCanonicalAttsFromPool(ctx, blockRoot, signed); err != nil {
+	if err := s.forkchoiceUpdateWithExecution(ctx, headRoot, s.CurrentSlot()+1); err != nil {
 		return err
 	}

@@ -295,7 +312,7 @@ func getStateVersionAndPayload(st state.BeaconState) (int, interfaces.ExecutionD
 	return preStateVersion, preStateHeader, nil
 }

-func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.SignedBeaconBlock,
+func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.ReadOnlySignedBeaconBlock,
 	blockRoots [][32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlockBatch")
 	defer span.End()
@@ -332,11 +349,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.SignedBeac

 	jCheckpoints := make([]*ethpb.Checkpoint, len(blks))
 	fCheckpoints := make([]*ethpb.Checkpoint, len(blks))
-	sigSet := &bls.SignatureBatch{
-		Signatures: [][]byte{},
-		PublicKeys: []bls.PublicKey{},
-		Messages:   [][32]byte{},
-	}
+	sigSet := bls.NewSet()
 	type versionAndHeader struct {
 		version int
 		header  interfaces.ExecutionData
@@ -376,7 +389,13 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.SignedBeac
 		}
 		sigSet.Join(set)
 	}
-	verify, err := sigSet.Verify()
+
+	var verify bool
+	if features.Get().EnableVerboseSigVerification {
+		verify, err = sigSet.VerifyVerbosely()
+	} else {
+		verify, err = sigSet.Verify()
+	}
 	if err != nil {
 		return invalidBlock{error: err}
 	}
@@ -428,12 +447,22 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.SignedBeac
 			}
 		}
 	}
+	// Save boundary states that will be useful for forkchoice
+	for r, st := range boundaries {
+		if err := s.cfg.StateGen.SaveState(ctx, r, st); err != nil {
+			return err
+		}
+	}
+	// Also saves the last post state which to be used as pre state for the next batch.
+	lastBR := blockRoots[len(blks)-1]
+	if err := s.cfg.StateGen.SaveState(ctx, lastBR, preState); err != nil {
+		return err
+	}
 	// Insert all nodes but the last one to forkchoice
-	if err := s.cfg.ForkChoiceStore.InsertOptimisticChain(ctx, pendingNodes); err != nil {
+	if err := s.cfg.ForkChoiceStore.InsertChain(ctx, pendingNodes); err != nil {
 		return errors.Wrap(err, "could not insert batch to forkchoice")
 	}
 	// Insert the last block to forkchoice
-	lastBR := blockRoots[len(blks)-1]
 	if err := s.cfg.ForkChoiceStore.InsertNode(ctx, preState, lastBR); err != nil {
 		return errors.Wrap(err, "could not insert last block in batch to forkchoice")
 	}
@@ -443,17 +472,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []interfaces.SignedBeac
 			return errors.Wrap(err, "could not set optimistic block to valid")
 		}
 	}
-
-	for r, st := range boundaries {
-		if err := s.cfg.StateGen.SaveState(ctx, r, st); err != nil {
-			return err
-		}
-	}
-	// Also saves the last post state which to be used as pre state for the next batch.
 	lastB := blks[len(blks)-1]
-	if err := s.cfg.StateGen.SaveState(ctx, lastBR, preState); err != nil {
-		return err
-	}
 	arg := &notifyForkchoiceUpdateArg{
 		headState: preState,
 		headRoot:  lastBR,
@@ -470,6 +489,7 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco
 	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)
@@ -484,27 +504,27 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco
 			return err
 		}
 	} else if postState.Slot() >= s.nextEpochBoundarySlot {
-		s.headLock.RLock()
-		st := s.head.state
-		s.headLock.RUnlock()
-		if err := reportEpochMetrics(ctx, postState, st); err != nil {
-			return err
-		}
-
-		var err error
 		s.nextEpochBoundarySlot, err = slots.EpochStart(coreTime.NextEpoch(postState))
 		if err != nil {
 			return err
 		}

 		// Update caches at epoch boundary slot.
-		// The following updates have short cut to return nil cheaply if fulfilled during boundary slot - 1.
+		// 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
+		}
 	}

 	return nil
@@ -512,7 +532,7 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState state.Beaco

 // 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.BeaconBlock, root [32]byte, st state.BeaconState) error {
+func (s *Service) insertBlockToForkchoiceStore(ctx context.Context, blk interfaces.ReadOnlyBeaconBlock, root [32]byte, st state.BeaconState) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.insertBlockToForkchoiceStore")
 	defer span.End()

@@ -524,16 +544,12 @@ func (s *Service) insertBlockToForkchoiceStore(ctx context.Context, blk interfac
 		}
 	}

-	if err := s.cfg.ForkChoiceStore.InsertNode(ctx, st, root); err != nil {
-		return err
-	}
-
-	return nil
+	return s.cfg.ForkChoiceStore.InsertNode(ctx, st, root)
 }

 // This feeds in the attestations included in the block to fork choice store. It's allows fork choice store
 // to gain information on the most current chain.
-func (s *Service) handleBlockAttestations(ctx context.Context, blk interfaces.BeaconBlock, st state.BeaconState) error {
+func (s *Service) handleBlockAttestations(ctx context.Context, blk interfaces.ReadOnlyBeaconBlock, st state.BeaconState) error {
 	// Feed in block's attestations to fork choice store.
 	for _, a := range blk.Body().Attestations() {
 		committee, err := helpers.BeaconCommitteeFromState(ctx, st, a.Data.Slot, a.Data.CommitteeIndex)
@@ -556,18 +572,19 @@ func (s *Service) handleBlockAttestations(ctx context.Context, blk interfaces.Be

 // InsertSlashingsToForkChoiceStore inserts attester slashing indices to fork choice store.
 // To call this function, it's caller's responsibility to ensure the slashing object is valid.
+// This function requires a write lock on forkchoice.
 func (s *Service) InsertSlashingsToForkChoiceStore(ctx context.Context, slashings []*ethpb.AttesterSlashing) {
 	for _, slashing := range slashings {
 		indices := blocks.SlashableAttesterIndices(slashing)
 		for _, index := range indices {
-			s.ForkChoicer().InsertSlashedIndex(ctx, types.ValidatorIndex(index))
+			s.ForkChoicer().InsertSlashedIndex(ctx, primitives.ValidatorIndex(index))
 		}
 	}
 }

 // This saves post state info to DB or cache. This also saves post state info to fork choice store.
 // Post state info consists of processed block and state. Do not call this method unless the block and state are verified.
-func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b interfaces.SignedBeaconBlock, st state.BeaconState) error {
+func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b interfaces.ReadOnlySignedBeaconBlock, st state.BeaconState) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.savePostStateInfo")
 	defer span.End()
 	if err := s.cfg.BeaconDB.SaveBlock(ctx, b); err != nil {
@@ -579,17 +596,8 @@ func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b interface
 	return nil
 }

-// This removes the attestations from the mem pool. It will only remove the attestations if input root `r` is canonical,
-// meaning the block `b` is part of the canonical chain.
-func (s *Service) pruneCanonicalAttsFromPool(ctx context.Context, r [32]byte, b interfaces.SignedBeaconBlock) error {
-	canonical, err := s.IsCanonical(ctx, r)
-	if err != nil {
-		return err
-	}
-	if !canonical {
-		return nil
-	}
-
+// This removes the attestations in block `b` from the attestation mem pool.
+func (s *Service) pruneAttsFromPool(b interfaces.ReadOnlySignedBeaconBlock) error {
 	atts := b.Block().Body().Attestations()
 	for _, att := range atts {
 		if helpers.IsAggregated(att) {
@@ -606,7 +614,7 @@ func (s *Service) pruneCanonicalAttsFromPool(ctx context.Context, r [32]byte, b
 }

 // validateMergeTransitionBlock validates the merge transition block.
-func (s *Service) validateMergeTransitionBlock(ctx context.Context, stateVersion int, stateHeader interfaces.ExecutionData, blk interfaces.SignedBeaconBlock) error {
+func (s *Service) validateMergeTransitionBlock(ctx context.Context, stateVersion int, stateHeader interfaces.ExecutionData, blk interfaces.ReadOnlySignedBeaconBlock) error {
 	// Skip validation if block is older than Bellatrix.
 	if blocks.IsPreBellatrixVersion(blk.Block().Version()) {
 		return nil
@@ -659,33 +667,15 @@ func (s *Service) fillMissingPayloadIDRoutine(ctx context.Context, stateFeed *ev
 			break
 		}

-		ticker := time.NewTicker(time.Second)
-		defer ticker.Stop()
+		attThreshold := params.BeaconConfig().SecondsPerSlot / 3
+		ticker := slots.NewSlotTickerWithOffset(s.genesisTime, time.Duration(attThreshold)*time.Second, params.BeaconConfig().SecondsPerSlot)
 		for {
 			select {
-			case ti := <-ticker.C:
-				if !atHalfSlot(ti) {
-					continue
+			case <-ticker.C():
+				if err := s.fillMissingBlockPayloadId(ctx); err != nil {
+					log.WithError(err).Error("Could not fill missing payload ID")
 				}
-				// Head root should be empty when retrieving proposer index for the next slot.
-				_, id, has := s.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(s.CurrentSlot()+1, [32]byte{} /* head root */)
-				// There exists proposer for next slot, but we haven't called fcu w/ payload attribute yet.
-				if has && id == [8]byte{} {
-					headBlock, err := s.headBlock()
-					if err != nil {
-						log.WithError(err).Error("Could not get head block")
-					} else {
-						if _, err := s.notifyForkchoiceUpdate(ctx, &notifyForkchoiceUpdateArg{
-							headState: s.headState(ctx),
-							headRoot:  s.headRoot(),
-							headBlock: headBlock.Block(),
-						}); err != nil {
-							log.WithError(err).Error("Could not prepare payload on empty ID")
-						}
-					}
-					missedPayloadIDFilledCount.Inc()
-				}
-			case <-s.ctx.Done():
+			case <-ctx.Done():
 				log.Debug("Context closed, exiting routine")
 				return
 			}
@@ -693,8 +683,32 @@ func (s *Service) fillMissingPayloadIDRoutine(ctx context.Context, stateFeed *ev
 	}()
 }

-// Returns true if time `t` is halfway through the slot in sec.
-func atHalfSlot(t time.Time) bool {
-	s := params.BeaconConfig().SecondsPerSlot
-	return uint64(t.Second())%s == s/2
+func (s *Service) fillMissingBlockPayloadId(ctx context.Context) error {
+	s.ForkChoicer().RLock()
+	highestReceivedSlot := s.cfg.ForkChoiceStore.HighestReceivedBlockSlot()
+	s.ForkChoicer().RUnlock()
+	if s.CurrentSlot() == highestReceivedSlot {
+		return nil
+	}
+	// Head root should be empty when retrieving proposer index for the next slot.
+	_, id, has := s.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(s.CurrentSlot()+1, [32]byte{} /* head root */)
+	// There exists proposer for next slot, but we haven't called fcu w/ payload attribute yet.
+	if !has || id != [8]byte{} {
+		return nil
+	}
+	missedPayloadIDFilledCount.Inc()
+	s.headLock.RLock()
+	headBlock, err := s.headBlock()
+	if err != nil {
+		return err
+	}
+	headState := s.headState(ctx)
+	headRoot := s.headRoot()
+	s.headLock.RUnlock()
+	_, err = s.notifyForkchoiceUpdate(ctx, &notifyForkchoiceUpdateArg{
+		headState: headState,
+		headRoot:  headRoot,
+		headBlock: headBlock.Block(),
+	})
+	return err
 }
--- a/beacon-chain/blockchain/process_block_helpers.go
+++ b/beacon-chain/blockchain/process_block_helpers.go
@@ -1,35 +1,32 @@
 package blockchain

 import (
-	"bytes"
 	"context"
 	"fmt"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	mathutil "github.com/prysmaticlabs/prysm/v3/math"
-	"github.com/prysmaticlabs/prysm/v3/monitoring/tracing"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 	"go.opencensus.io/trace"
 )

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

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

@@ -60,7 +57,7 @@ func (s *Service) getBlockPreState(ctx context.Context, b interfaces.BeaconBlock
 }

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

@@ -72,10 +69,6 @@ func (s *Service) verifyBlkPreState(ctx context.Context, b interfaces.BeaconBloc
 		return errors.New("could not reconstruct parent state")
 	}

-	if err := s.VerifyFinalizedBlkDescendant(ctx, parentRoot); err != nil {
-		return err
-	}
-
 	has, err := s.cfg.StateGen.HasState(ctx, parentRoot)
 	if err != nil {
 		return err
@@ -89,38 +82,9 @@ func (s *Service) verifyBlkPreState(ctx context.Context, b interfaces.BeaconBloc
 	return nil
 }

-// VerifyFinalizedBlkDescendant validates if input block root is a descendant of the
-// current finalized block root.
-func (s *Service) VerifyFinalizedBlkDescendant(ctx context.Context, root [32]byte) error {
-	ctx, span := trace.StartSpan(ctx, "blockChain.VerifyFinalizedBlkDescendant")
-	defer span.End()
-	finalized := s.ForkChoicer().FinalizedCheckpoint()
-	fRoot := s.ensureRootNotZeros(finalized.Root)
-	fSlot, err := slots.EpochStart(finalized.Epoch)
-	if err != nil {
-		return err
-	}
-	bFinalizedRoot, err := s.ancestor(ctx, root[:], fSlot)
-	if err != nil {
-		return errors.Wrap(err, "could not get finalized block root")
-	}
-	if bFinalizedRoot == nil {
-		return fmt.Errorf("no finalized block known for block %#x", bytesutil.Trunc(root[:]))
-	}
-
-	if !bytes.Equal(bFinalizedRoot, fRoot[:]) {
-		err := fmt.Errorf("block %#x is not a descendant of the current finalized block slot %d, %#x != %#x",
-			bytesutil.Trunc(root[:]), fSlot, bytesutil.Trunc(bFinalizedRoot),
-			bytesutil.Trunc(fRoot[:]))
-		tracing.AnnotateError(span, err)
-		return invalidBlock{error: err}
-	}
-	return nil
-}
-
 // verifyBlkFinalizedSlot validates input block is not less than or equal
 // to current finalized slot.
-func (s *Service) verifyBlkFinalizedSlot(b interfaces.BeaconBlock) error {
+func (s *Service) verifyBlkFinalizedSlot(b interfaces.ReadOnlyBeaconBlock) error {
 	finalized := s.ForkChoicer().FinalizedCheckpoint()
 	finalizedSlot, err := slots.EpochStart(finalized.Epoch)
 	if err != nil {
@@ -185,23 +149,24 @@ func (s *Service) updateFinalized(ctx context.Context, cp *ethpb.Checkpoint) err
 // ancestor returns the block root of an ancestry block from the input block root.
 //
 // Spec pseudocode definition:
-//   def get_ancestor(store: Store, root: Root, slot: Slot) -> Root:
-//    block = store.blocks[root]
-//    if block.slot > slot:
-//        return get_ancestor(store, block.parent_root, slot)
-//    elif block.slot == slot:
-//        return root
-//    else:
-//        # root is older than queried slot, thus a skip slot. Return most recent root prior to slot
-//        return root
-func (s *Service) ancestor(ctx context.Context, root []byte, slot types.Slot) ([]byte, error) {
+//
+//	def get_ancestor(store: Store, root: Root, slot: Slot) -> Root:
+//	 block = store.blocks[root]
+//	 if block.slot > slot:
+//	     return get_ancestor(store, block.parent_root, slot)
+//	 elif block.slot == slot:
+//	     return root
+//	 else:
+//	     # root is older than queried slot, thus a skip slot. Return most recent root prior to slot
+//	     return root
+func (s *Service) ancestor(ctx context.Context, root []byte, slot primitives.Slot) ([]byte, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ancestor")
 	defer span.End()

 	r := bytesutil.ToBytes32(root)
 	// Get ancestor root from fork choice store instead of recursively looking up blocks in DB.
 	// This is most optimal outcome.
-	ar, err := s.ancestorByForkChoiceStore(ctx, r, slot)
+	ar, err := s.cfg.ForkChoiceStore.AncestorRoot(ctx, r, slot)
 	if err != nil {
 		// Try getting ancestor root from DB when failed to retrieve from fork choice store.
 		// This is the second line of defense for retrieving ancestor root.
@@ -211,38 +176,28 @@ func (s *Service) ancestor(ctx context.Context, root []byte, slot types.Slot) ([
 		}
 	}

-	return ar, nil
-}
-
-// This retrieves an ancestor root using fork choice store. The look up is looping through the a flat array structure.
-func (s *Service) ancestorByForkChoiceStore(ctx context.Context, r [32]byte, slot types.Slot) ([]byte, error) {
-	ctx, span := trace.StartSpan(ctx, "blockChain.ancestorByForkChoiceStore")
-	defer span.End()
-
-	if !s.cfg.ForkChoiceStore.HasParent(r) {
-		return nil, errors.New("could not find root in fork choice store")
-	}
-	root, err := s.cfg.ForkChoiceStore.AncestorRoot(ctx, r, slot)
-	return root[:], err
+	return ar[:], nil
 }

 // This retrieves an ancestor root using DB. The look up is recursively looking up DB. Slower than `ancestorByForkChoiceStore`.
-func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot types.Slot) ([]byte, error) {
+func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot primitives.Slot) (root [32]byte, err error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ancestorByDB")
 	defer span.End()

+	root = [32]byte{}
 	// Stop recursive ancestry lookup if context is cancelled.
 	if ctx.Err() != nil {
-		return nil, ctx.Err()
+		err = ctx.Err()
+		return
 	}

 	signed, err := s.getBlock(ctx, r)
 	if err != nil {
-		return nil, err
+		return root, err
 	}
 	b := signed.Block()
 	if b.Slot() == slot || b.Slot() < slot {
-		return r[:], nil
+		return r, nil
 	}

 	return s.ancestorByDB(ctx, b.ParentRoot(), slot)
@@ -250,7 +205,7 @@ func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot types.Slot)

 // This retrieves missing blocks from DB (ie. the blocks that couldn't be received over sync) and inserts them to fork choice store.
 // This is useful for block tree visualizer and additional vote accounting.
-func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk interfaces.BeaconBlock,
+func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk interfaces.ReadOnlyBeaconBlock,
 	fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
 	pendingNodes := make([]*forkchoicetypes.BlockAndCheckpoints, 0)

@@ -282,9 +237,9 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk interfa
 		return nil
 	}
 	if root != s.ensureRootNotZeros(finalized.Root) && !s.ForkChoicer().HasNode(root) {
-		return errNotDescendantOfFinalized
+		return ErrNotDescendantOfFinalized
 	}
-	return s.cfg.ForkChoiceStore.InsertOptimisticChain(ctx, pendingNodes)
+	return s.cfg.ForkChoiceStore.InsertChain(ctx, pendingNodes)
 }

 // inserts finalized deposits into our finalized deposit trie.
@@ -316,23 +271,6 @@ func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) e
 	return nil
 }

-// The deletes input attestations from the attestation pool, so proposers don't include them in a block for the future.
-func (s *Service) deletePoolAtts(atts []*ethpb.Attestation) error {
-	for _, att := range atts {
-		if helpers.IsAggregated(att) {
-			if err := s.cfg.AttPool.DeleteAggregatedAttestation(att); err != nil {
-				return err
-			}
-		} else {
-			if err := s.cfg.AttPool.DeleteUnaggregatedAttestation(att); err != nil {
-				return err
-			}
-		}
-	}
-
-	return nil
-}
-
 // This ensures that the input root defaults to using genesis root instead of zero hashes. This is needed for handling
 // fork choice justification routine.
 func (s *Service) ensureRootNotZeros(root [32]byte) [32]byte {
--- a/beacon-chain/blockchain/process_block_test.go
+++ b/beacon-chain/blockchain/process_block_test.go
@@ -22,7 +22,6 @@ import (
 	testDB "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/execution"
 	mockExecution "github.com/prysmaticlabs/prysm/v3/beacon-chain/execution/testing"
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/attestations"
@@ -32,7 +31,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	enginev1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
@@ -58,7 +57,7 @@ func TestStore_OnBlock(t *testing.T) {

 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)
-	genesisStateRoot := [32]byte{}
+	var genesisStateRoot [32]byte
 	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
 	util.SaveBlock(t, ctx, beaconDB, genesis)
 	validGenesisRoot, err := genesis.Block.HashTreeRoot()
@@ -66,6 +65,10 @@ func TestStore_OnBlock(t *testing.T) {
 	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()
@@ -74,11 +77,16 @@ func TestStore_OnBlock(t *testing.T) {
 	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
@@ -109,10 +117,11 @@ func TestStore_OnBlock(t *testing.T) {
 			blk: func() *ethpb.SignedBeaconBlock {
 				b := util.NewBeaconBlock()
 				b.Block.ParentRoot = randomParentRoot[:]
+				b.Block.Slot = 2
 				return b
 			}(),
 			s:             st.Copy(),
-			wantErrString: "is not a descendant of the current finalized block",
+			wantErrString: "not descendant of finalized checkpoint",
 		},
 		{
 			name: "same slot as finalized block",
@@ -158,10 +167,10 @@ func TestStore_OnBlockBatch(t *testing.T) {
 	require.NoError(t, service.saveGenesisData(ctx, st))
 	bState := st.Copy()

-	var blks []interfaces.SignedBeaconBlock
+	var blks []interfaces.ReadOnlySignedBeaconBlock
 	var blkRoots [][32]byte
 	for i := 0; i < 97; i++ {
-		b, err := util.GenerateFullBlock(bState, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlock(bState, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -182,7 +191,7 @@ func TestStore_OnBlockBatch(t *testing.T) {
 	jcp := service.CurrentJustifiedCheckpt()
 	jroot := bytesutil.ToBytes32(jcp.Root)
 	require.Equal(t, blkRoots[63], jroot)
-	require.Equal(t, types.Epoch(2), service.cfg.ForkChoiceStore.JustifiedCheckpoint().Epoch)
+	require.Equal(t, primitives.Epoch(2), service.cfg.ForkChoiceStore.JustifiedCheckpoint().Epoch)
 }

 func TestStore_OnBlockBatch_NotifyNewPayload(t *testing.T) {
@@ -201,11 +210,11 @@ func TestStore_OnBlockBatch_NotifyNewPayload(t *testing.T) {
 	require.NoError(t, service.saveGenesisData(ctx, st))
 	bState := st.Copy()

-	var blks []interfaces.SignedBeaconBlock
+	var blks []interfaces.ReadOnlySignedBeaconBlock
 	var blkRoots [][32]byte
 	blkCount := 4
 	for i := 0; i <= blkCount; i++ {
-		b, err := util.GenerateFullBlock(bState, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlock(bState, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -236,7 +245,7 @@ func TestCachedPreState_CanGetFromStateSummary(t *testing.T) {

 	st, keys := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, st))
-	b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), types.Slot(1))
+	b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(1))
 	require.NoError(t, err)
 	root, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)
@@ -361,7 +370,7 @@ func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
 	require.NoError(t, err)
 	service.cfg.ForkChoiceStore = doublylinkedtree.New()

-	genesisStateRoot := [32]byte{}
+	var genesisStateRoot [32]byte
 	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
 	util.SaveBlock(t, ctx, beaconDB, genesis)
 	validGenesisRoot, err := genesis.Block.HashTreeRoot()
@@ -420,7 +429,7 @@ func TestFillForkChoiceMissingBlocks_FinalizedSibling(t *testing.T) {
 	require.NoError(t, err)
 	service.cfg.ForkChoiceStore = doublylinkedtree.New()

-	genesisStateRoot := [32]byte{}
+	var genesisStateRoot [32]byte
 	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
 	util.SaveBlock(t, ctx, beaconDB, genesis)
 	validGenesisRoot, err := genesis.Block.HashTreeRoot()
@@ -442,13 +451,16 @@ func TestFillForkChoiceMissingBlocks_FinalizedSibling(t *testing.T) {

 	err = service.fillInForkChoiceMissingBlocks(
 		context.Background(), wsb.Block(), beaconState.FinalizedCheckpoint(), beaconState.CurrentJustifiedCheckpoint())
-	require.Equal(t, errNotDescendantOfFinalized.Error(), err.Error())
+	require.Equal(t, ErrNotDescendantOfFinalized.Error(), err.Error())
 }

 // blockTree1 constructs the following tree:
-//    /- B1
+//
+//	/- B1
+//
 // B0           /- B5 - B7
-//    \- B3 - B4 - B6 - B8
+//
+//	\- B3 - B4 - B6 - B8
 func blockTree1(t *testing.T, beaconDB db.Database, genesisRoot []byte) ([][]byte, error) {
 	genesisRoot = bytesutil.PadTo(genesisRoot, 32)
 	b0 := util.NewBeaconBlock()
@@ -539,7 +551,7 @@ func TestCurrentSlot_HandlesOverflow(t *testing.T) {
 	svc := Service{genesisTime: prysmTime.Now().Add(1 * time.Hour)}

 	slot := svc.CurrentSlot()
-	require.Equal(t, types.Slot(0), slot, "Unexpected slot")
+	require.Equal(t, primitives.Slot(0), slot, "Unexpected slot")
 }
 func TestAncestorByDB_CtxErr(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
@@ -705,87 +717,6 @@ func TestEnsureRootNotZeroHashes(t *testing.T) {
 	assert.Equal(t, root, r, "Did not get wanted justified root")
 }

-func TestVerifyBlkDescendant(t *testing.T) {
-	beaconDB := testDB.SetupDB(t)
-	ctx := context.Background()
-
-	fcs := doublylinkedtree.New()
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB, fcs)),
-		WithForkChoiceStore(fcs),
-	}
-	b := util.NewBeaconBlock()
-	b.Block.Slot = 32
-	r, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	util.SaveBlock(t, ctx, beaconDB, b)
-
-	b1 := util.NewBeaconBlock()
-	b1.Block.Slot = 32
-	b1.Block.Body.Graffiti = bytesutil.PadTo([]byte{'a'}, 32)
-	r1, err := b1.Block.HashTreeRoot()
-	require.NoError(t, err)
-	util.SaveBlock(t, ctx, beaconDB, b1)
-
-	type args struct {
-		parentRoot    [32]byte
-		finalizedRoot [32]byte
-	}
-	tests := []struct {
-		name             string
-		args             args
-		wantedErr        string
-		invalidBlockRoot bool
-	}{
-		{
-			name: "could not get finalized block in block service cache",
-			args: args{
-				finalizedRoot: [32]byte{'a'},
-			},
-			wantedErr: "block not found in cache or db",
-		},
-		{
-			name: "could not get finalized block root in DB",
-			args: args{
-				finalizedRoot: r,
-				parentRoot:    [32]byte{'a'},
-			},
-			wantedErr: "could not get finalized block root",
-		},
-		{
-			name: "is not descendant",
-			args: args{
-				finalizedRoot: r1,
-				parentRoot:    r,
-			},
-			wantedErr:        "is not a descendant of the current finalized block slot",
-			invalidBlockRoot: true,
-		},
-		{
-			name: "is descendant",
-			args: args{
-				finalizedRoot: r,
-				parentRoot:    r,
-			},
-		},
-	}
-	for _, tt := range tests {
-		service, err := NewService(ctx, opts...)
-		require.NoError(t, err)
-		require.NoError(t, service.ForkChoicer().UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Root: tt.args.finalizedRoot, Epoch: 1}))
-		err = service.VerifyFinalizedBlkDescendant(ctx, tt.args.parentRoot)
-		if tt.wantedErr != "" {
-			assert.ErrorContains(t, tt.wantedErr, err)
-			if tt.invalidBlockRoot {
-				require.Equal(t, true, IsInvalidBlock(err))
-			}
-		} else if err != nil {
-			assert.NoError(t, err)
-		}
-	}
-}
-
 func TestHandleEpochBoundary_UpdateFirstSlot(t *testing.T) {
 	ctx := context.Background()
 	opts := testServiceOptsNoDB()
@@ -821,7 +752,7 @@ func TestOnBlock_CanFinalize_WithOnTick(t *testing.T) {
 	require.NoError(t, fcs.UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Root: service.originBlockRoot}))

 	testState := gs.Copy()
-	for i := types.Slot(1); i <= 4*params.BeaconConfig().SlotsPerEpoch; i++ {
+	for i := primitives.Slot(1); i <= 4*params.BeaconConfig().SlotsPerEpoch; i++ {
 		blk, err := util.GenerateFullBlock(testState, keys, util.DefaultBlockGenConfig(), i)
 		require.NoError(t, err)
 		r, err := blk.Block.HashTreeRoot()
@@ -834,9 +765,9 @@ func TestOnBlock_CanFinalize_WithOnTick(t *testing.T) {
 		require.NoError(t, err)
 	}
 	cp := service.CurrentJustifiedCheckpt()
-	require.Equal(t, types.Epoch(3), cp.Epoch)
+	require.Equal(t, primitives.Epoch(3), cp.Epoch)
 	cp = service.FinalizedCheckpt()
-	require.Equal(t, types.Epoch(2), cp.Epoch)
+	require.Equal(t, primitives.Epoch(2), cp.Epoch)

 	// The update should persist in DB.
 	j, err := service.cfg.BeaconDB.JustifiedCheckpoint(ctx)
@@ -870,7 +801,7 @@ func TestOnBlock_CanFinalize(t *testing.T) {
 	require.NoError(t, service.saveGenesisData(ctx, gs))

 	testState := gs.Copy()
-	for i := types.Slot(1); i <= 4*params.BeaconConfig().SlotsPerEpoch; i++ {
+	for i := primitives.Slot(1); i <= 4*params.BeaconConfig().SlotsPerEpoch; i++ {
 		blk, err := util.GenerateFullBlock(testState, keys, util.DefaultBlockGenConfig(), i)
 		require.NoError(t, err)
 		r, err := blk.Block.HashTreeRoot()
@@ -882,9 +813,9 @@ func TestOnBlock_CanFinalize(t *testing.T) {
 		require.NoError(t, err)
 	}
 	cp := service.CurrentJustifiedCheckpt()
-	require.Equal(t, types.Epoch(3), cp.Epoch)
+	require.Equal(t, primitives.Epoch(3), cp.Epoch)
 	cp = service.FinalizedCheckpt()
-	require.Equal(t, types.Epoch(2), cp.Epoch)
+	require.Equal(t, primitives.Epoch(2), cp.Epoch)

 	// The update should persist in DB.
 	j, err := service.cfg.BeaconDB.JustifiedCheckpoint(ctx)
@@ -972,7 +903,7 @@ func TestOnBlock_CallNewPayloadAndForkchoiceUpdated(t *testing.T) {
 	gs, keys := util.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
 	testState := gs.Copy()
-	for i := types.Slot(1); i < params.BeaconConfig().SlotsPerEpoch; i++ {
+	for i := primitives.Slot(1); i < params.BeaconConfig().SlotsPerEpoch; i++ {
 		blk, err := util.GenerateFullBlock(testState, keys, util.DefaultBlockGenConfig(), i)
 		require.NoError(t, err)
 		r, err := blk.Block.HashTreeRoot()
@@ -1000,7 +931,7 @@ func TestInsertFinalizedDeposits(t *testing.T) {
 	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))
-	zeroSig := [96]byte{}
+	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{
@@ -1038,7 +969,7 @@ func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
 	assert.NoError(t, gs2.SetEth1Data(&ethpb.Eth1Data{DepositCount: 15}))
 	assert.NoError(t, gs2.SetEth1DepositIndex(13))
 	assert.NoError(t, service.cfg.StateGen.SaveState(ctx, [32]byte{'m', 'o', 'c', 'k', '2'}, gs2))
-	zeroSig := [96]byte{}
+	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{
@@ -1070,7 +1001,7 @@ func TestInsertFinalizedDeposits_MultipleFinalizedRoutines(t *testing.T) {
 	}
 }

-func TestRemoveBlockAttestationsInPool_Canonical(t *testing.T) {
+func TestRemoveBlockAttestationsInPool(t *testing.T) {
 	genesis, keys := util.DeterministicGenesisState(t, 64)
 	b, err := util.GenerateFullBlock(genesis, keys, util.DefaultBlockGenConfig(), 1)
 	assert.NoError(t, err)
@@ -1087,29 +1018,10 @@ func TestRemoveBlockAttestationsInPool_Canonical(t *testing.T) {
 	require.NoError(t, service.cfg.AttPool.SaveAggregatedAttestations(atts))
 	wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 	require.NoError(t, err)
-	require.NoError(t, service.pruneCanonicalAttsFromPool(ctx, r, wsb))
+	require.NoError(t, service.pruneAttsFromPool(wsb))
 	require.Equal(t, 0, service.cfg.AttPool.AggregatedAttestationCount())
 }

-func TestRemoveBlockAttestationsInPool_NonCanonical(t *testing.T) {
-	genesis, keys := util.DeterministicGenesisState(t, 64)
-	b, err := util.GenerateFullBlock(genesis, keys, util.DefaultBlockGenConfig(), 1)
-	assert.NoError(t, err)
-	r, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	service := setupBeaconChain(t, beaconDB)
-
-	atts := b.Block.Body.Attestations
-	require.NoError(t, service.cfg.AttPool.SaveAggregatedAttestations(atts))
-	wsb, err := consensusblocks.NewSignedBeaconBlock(b)
-	require.NoError(t, err)
-	require.NoError(t, service.pruneCanonicalAttsFromPool(ctx, r, wsb))
-	require.Equal(t, 1, service.cfg.AttPool.AggregatedAttestationCount())
-}
-
 func Test_getStateVersionAndPayload(t *testing.T) {
 	tests := []struct {
 		name    string
@@ -1510,7 +1422,7 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1523,7 +1435,7 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1537,7 +1449,7 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1548,7 +1460,7 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 	}
 	// Check that we haven't justified the second epoch yet
 	jc := service.ForkChoicer().JustifiedCheckpoint()
-	require.Equal(t, types.Epoch(0), jc.Epoch)
+	require.Equal(t, primitives.Epoch(0), jc.Epoch)

 	// import a block that justifies the second epoch
 	driftGenesisTime(service, 18, 0)
@@ -1563,10 +1475,10 @@ func TestStore_NoViableHead_FCU(t *testing.T) {
 	err = service.onBlock(ctx, wsb, firstInvalidRoot)
 	require.NoError(t, err)
 	jc = service.ForkChoicer().JustifiedCheckpoint()
-	require.Equal(t, types.Epoch(2), jc.Epoch)
+	require.Equal(t, primitives.Epoch(2), jc.Epoch)

 	sjc := validHeadState.CurrentJustifiedCheckpoint()
-	require.Equal(t, types.Epoch(0), sjc.Epoch)
+	require.Equal(t, primitives.Epoch(0), sjc.Epoch)
 	lvh := b.Block.Body.ExecutionPayload.ParentHash
 	// check our head
 	require.Equal(t, firstInvalidRoot, service.ForkChoicer().CachedHeadRoot())
@@ -1670,7 +1582,7 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1683,7 +1595,7 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1697,7 +1609,7 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1708,7 +1620,7 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 	}
 	// Check that we haven't justified the second epoch yet
 	jc := service.ForkChoicer().JustifiedCheckpoint()
-	require.Equal(t, types.Epoch(0), jc.Epoch)
+	require.Equal(t, primitives.Epoch(0), jc.Epoch)

 	// import a block that justifies the second epoch
 	driftGenesisTime(service, 18, 0)
@@ -1723,10 +1635,10 @@ func TestStore_NoViableHead_NewPayload(t *testing.T) {
 	err = service.onBlock(ctx, wsb, firstInvalidRoot)
 	require.NoError(t, err)
 	jc = service.ForkChoicer().JustifiedCheckpoint()
-	require.Equal(t, types.Epoch(2), jc.Epoch)
+	require.Equal(t, primitives.Epoch(2), jc.Epoch)

 	sjc := validHeadState.CurrentJustifiedCheckpoint()
-	require.Equal(t, types.Epoch(0), sjc.Epoch)
+	require.Equal(t, primitives.Epoch(0), sjc.Epoch)
 	lvh := b.Block.Body.ExecutionPayload.ParentHash
 	// check our head
 	require.Equal(t, firstInvalidRoot, service.ForkChoicer().CachedHeadRoot())
@@ -1831,7 +1743,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1844,7 +1756,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1872,7 +1784,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	require.NoError(t, err)
 	lvh := b.Block.Body.ExecutionPayload.BlockHash
 	validjc := validHeadState.CurrentJustifiedCheckpoint()
-	require.Equal(t, types.Epoch(0), validjc.Epoch)
+	require.Equal(t, primitives.Epoch(0), validjc.Epoch)

 	// import blocks 13 through 18 to justify 12
 	invalidRoots := make([][32]byte, 19-13)
@@ -1880,7 +1792,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1891,7 +1803,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	}
 	// Check that we have justified the second epoch
 	jc := service.ForkChoicer().JustifiedCheckpoint()
-	require.Equal(t, types.Epoch(2), jc.Epoch)
+	require.Equal(t, primitives.Epoch(2), jc.Epoch)
 	invalidHeadRoot := service.ForkChoicer().CachedHeadRoot()

 	// import block 19 to find out that the whole chain 13--18 was in fact
@@ -1929,7 +1841,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	// Check that the node's justified checkpoint does not agree with the
 	// last valid state's justified checkpoint
 	sjc := service.CurrentJustifiedCheckpt()
-	require.Equal(t, types.Epoch(2), sjc.Epoch)
+	require.Equal(t, primitives.Epoch(2), sjc.Epoch)

 	// import another block based on the last valid head state
 	mockEngine = &mockExecution.EngineClient{}
@@ -1953,7 +1865,7 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	for i := 21; i < 30; i++ {
 		driftGenesisTime(service, int64(i), 0)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -1983,14 +1895,12 @@ func TestStore_NoViableHead_Liveness(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, root, service.ForkChoicer().CachedHeadRoot())
 	sjc = service.CurrentJustifiedCheckpt()
-	require.Equal(t, types.Epoch(4), sjc.Epoch)
+	require.Equal(t, primitives.Epoch(4), sjc.Epoch)
 	optimistic, err = service.IsOptimistic(ctx)
 	require.NoError(t, err)
 	require.Equal(t, false, optimistic)
 }

-type newForkChoicer func() forkchoice.ForkChoicer
-
 // See the description in #10777 and #10782 for the full setup
 // We sync optimistically a chain of blocks. Block 12 is the first block in Epoch
 // 2 (and the merge block in this sequence). Block 18 justifies it and Block 19 returns
@@ -2011,10 +1921,12 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	attSrv, err := attestations.NewService(ctx, &attestations.Config{})
 	require.NoError(t, err)
 	newfc := doublylinkedtree.New()
+	newStateGen := stategen.New(beaconDB, newfc)
+	newfc.SetBalancesByRooter(newStateGen.ActiveNonSlashedBalancesByRoot)
 	opts := []Option{
 		WithDatabase(beaconDB),
 		WithAttestationPool(attestations.NewPool()),
-		WithStateGen(stategen.New(beaconDB, newfc)),
+		WithStateGen(newStateGen),
 		WithForkChoiceStore(newfc),
 		WithStateNotifier(&mock.MockStateNotifier{}),
 		WithExecutionEngineCaller(mockEngine),
@@ -2042,7 +1954,7 @@ func TestNoViableHead_Reboot(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlock(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -2055,7 +1967,7 @@ func TestNoViableHead_Reboot(t *testing.T) {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockAltair(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -2083,14 +1995,14 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	require.NoError(t, err)
 	lvh := b.Block.Body.ExecutionPayload.BlockHash
 	validjc := validHeadState.CurrentJustifiedCheckpoint()
-	require.Equal(t, types.Epoch(0), validjc.Epoch)
+	require.Equal(t, primitives.Epoch(0), validjc.Epoch)

 	// import blocks 13 through 18 to justify 12
 	for i := 13; i < 19; i++ {
 		driftGenesisTime(service, int64(i), 0)
 		st, err := service.HeadState(ctx)
 		require.NoError(t, err)
-		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), primitives.Slot(i))
 		require.NoError(t, err)
 		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
 		require.NoError(t, err)
@@ -2100,7 +2012,7 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	}
 	// Check that we have justified the second epoch
 	jc := service.ForkChoicer().JustifiedCheckpoint()
-	require.Equal(t, types.Epoch(2), jc.Epoch)
+	require.Equal(t, primitives.Epoch(2), jc.Epoch)

 	// import block 19 to find out that the whole chain 13--18 was in fact
 	// invalid
@@ -2124,6 +2036,12 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	require.Equal(t, blk, nil)

 	service.cfg.ForkChoiceStore = doublylinkedtree.New()
+	justified, err := service.cfg.BeaconDB.JustifiedCheckpoint(ctx)
+	require.NoError(t, err)
+
+	jroot := bytesutil.ToBytes32(justified.Root)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, genesisState, jroot))
+	service.cfg.ForkChoiceStore.SetBalancesByRooter(service.cfg.StateGen.ActiveNonSlashedBalancesByRoot)
 	require.NoError(t, service.StartFromSavedState(genesisState))

 	// Forkchoice has the genesisRoot loaded at startup
@@ -2135,12 +2053,11 @@ func TestNoViableHead_Reboot(t *testing.T) {
 	optimistic, err := service.IsOptimistic(ctx)
 	require.NoError(t, err)
 	require.Equal(t, false, optimistic)
-	require.Equal(t, false, service.ForkChoicer().AllTipsAreInvalid())

 	// Check that the node's justified checkpoint does not agree with the
 	// last valid state's justified checkpoint
 	sjc := service.CurrentJustifiedCheckpt()
-	require.Equal(t, types.Epoch(2), sjc.Epoch)
+	require.Equal(t, primitives.Epoch(2), sjc.Epoch)

 	// import another block based on the last valid head state
 	mockEngine = &mockExecution.EngineClient{}
@@ -2152,68 +2069,17 @@ 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))
-	// Check that the head is still INVALID and the node is optimistic
+	// We use onBlockBatch here because the valid chain is missing in forkchoice
+	require.NoError(t, service.onBlockBatch(ctx, []interfaces.ReadOnlySignedBeaconBlock{wsb}, [][32]byte{root}))
+	// Check that the head is now VALID and the node is not optimistic
 	require.Equal(t, genesisRoot, service.ensureRootNotZeros(service.ForkChoicer().CachedHeadRoot()))
 	headRoot, err = service.HeadRoot(ctx)
 	require.NoError(t, err)
-	require.Equal(t, genesisRoot, bytesutil.ToBytes32(headRoot))
-
-	optimistic, err = service.IsOptimistic(ctx)
-	require.NoError(t, err)
-	require.Equal(t, true, optimistic)
-	require.Equal(t, true, service.ForkChoicer().AllTipsAreInvalid())
-	st, err = service.cfg.StateGen.StateByRoot(ctx, root)
-	require.NoError(t, err)
-
-	// Import blocks 21--23
-	for i := 21; i < 24; i++ {
-		driftGenesisTime(service, int64(i), 0)
-		require.NoError(t, err)
-		b, err := util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), types.Slot(i))
-		require.NoError(t, err)
-		wsb, err := consensusblocks.NewSignedBeaconBlock(b)
-		require.NoError(t, err)
-		root, err = b.Block.HashTreeRoot()
-		require.NoError(t, err)
-		err = service.onBlock(ctx, wsb, root)
-		require.NoError(t, err)
-		st, err = service.cfg.StateGen.StateByRoot(ctx, root)
-		require.NoError(t, err)
-	}
-	// Head should still be INVALID and the node is optimistic
-	require.Equal(t, genesisRoot, service.ensureRootNotZeros(service.ForkChoicer().CachedHeadRoot()))
-	headRoot, err = service.HeadRoot(ctx)
-	require.NoError(t, err)
-	require.Equal(t, genesisRoot, bytesutil.ToBytes32(headRoot))
-
-	optimistic, err = service.IsOptimistic(ctx)
-	require.NoError(t, err)
-	require.Equal(t, true, optimistic)
-	require.Equal(t, true, service.ForkChoicer().AllTipsAreInvalid())
-
-	// Import block 24, it should justify Epoch 3 and become HEAD, the node
-	// recovers
-	driftGenesisTime(service, 24, 0)
-	b, err = util.GenerateFullBlockBellatrix(st, keys, util.DefaultBlockGenConfig(), 24)
-	require.NoError(t, err)
-	wsb, err = consensusblocks.NewSignedBeaconBlock(b)
-	require.NoError(t, err)
-	root, err = b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	err = service.onBlock(ctx, wsb, root)
-	require.NoError(t, err)
-	require.Equal(t, root, service.ForkChoicer().CachedHeadRoot())
-	headRoot, err = service.HeadRoot(ctx)
-	require.NoError(t, err)
 	require.Equal(t, root, bytesutil.ToBytes32(headRoot))

-	sjc = service.CurrentJustifiedCheckpt()
-	require.Equal(t, types.Epoch(3), sjc.Epoch)
 	optimistic, err = service.IsOptimistic(ctx)
 	require.NoError(t, err)
 	require.Equal(t, false, optimistic)
-	require.Equal(t, false, service.ForkChoicer().AllTipsAreInvalid())
 }

 func TestOnBlock_HandleBlockAttestations(t *testing.T) {
@@ -2286,6 +2152,21 @@ func TestOnBlock_HandleBlockAttestations(t *testing.T) {
 	require.Equal(t, 1, len(service.cfg.AttPool.BlockAttestations()))
 }

+func TestFillMissingBlockPayloadId_DiffSlotExitEarly(t *testing.T) {
+	fc := doublylinkedtree.New()
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	opts := []Option{
+		WithForkChoiceStore(fc),
+		WithStateGen(stategen.New(beaconDB, fc)),
+	}
+
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	require.NoError(t, service.fillMissingBlockPayloadId(ctx), 0)
+}
+
 // Helper function to simulate the block being on time or delayed for proposer
 // boost. It alters the genesisTime tracked by the store.
 func driftGenesisTime(s *Service, slot int64, delay int64) {
--- a/beacon-chain/blockchain/receive_attestation.go
+++ b/beacon-chain/blockchain/receive_attestation.go
@@ -11,7 +11,9 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/feed"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v3/config/features"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
@@ -19,6 +21,10 @@ import (
 	"go.opencensus.io/trace"
 )

+// reorgLateBlockCountAttestations is the time until the end of the slot in which we count
+// attestations to see if we will reorg the incoming block
+const reorgLateBlockCountAttestations = 2 * time.Second
+
 // AttestationStateFetcher allows for retrieving a beacon state corresponding to the block
 // root of an attestation's target checkpoint.
 type AttestationStateFetcher interface {
@@ -29,7 +35,7 @@ type AttestationStateFetcher interface {
 type AttestationReceiver interface {
 	AttestationStateFetcher
 	VerifyLmdFfgConsistency(ctx context.Context, att *ethpb.Attestation) error
-	VerifyFinalizedConsistency(ctx context.Context, root []byte) error
+	InForkchoice([32]byte) bool
 }

 // AttestationTargetState returns the pre state of attestation.
@@ -60,33 +66,6 @@ func (s *Service) VerifyLmdFfgConsistency(ctx context.Context, a *ethpb.Attestat
 	return nil
 }

-// VerifyFinalizedConsistency verifies input root is consistent with finalized store.
-// When the input root is not be consistent with finalized store then we know it is not
-// on the finalized check point that leads to current canonical chain and should be rejected accordingly.
-func (s *Service) VerifyFinalizedConsistency(ctx context.Context, root []byte) error {
-	// A canonical root implies the root to has an ancestor that aligns with finalized check point.
-	// In this case, we could exit early to save on additional computation.
-	blockRoot := bytesutil.ToBytes32(root)
-	if s.cfg.ForkChoiceStore.HasNode(blockRoot) && s.cfg.ForkChoiceStore.IsCanonical(blockRoot) {
-		return nil
-	}
-
-	f := s.FinalizedCheckpt()
-	ss, err := slots.EpochStart(f.Epoch)
-	if err != nil {
-		return err
-	}
-	r, err := s.ancestor(ctx, root, ss)
-	if err != nil {
-		return err
-	}
-	if !bytes.Equal(f.Root, r) {
-		return errors.New("Root and finalized store are not consistent")
-	}
-
-	return nil
-}
-
 // This routine processes fork choice attestations from the pool to account for validator votes and fork choice.
 func (s *Service) spawnProcessAttestationsRoutine(stateFeed *event.Feed) {
 	// Wait for state to be initialized.
@@ -115,41 +94,54 @@ func (s *Service) spawnProcessAttestationsRoutine(stateFeed *event.Feed) {
 		}

 		st := slots.NewSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
+		pat := slots.NewSlotTickerWithOffset(s.genesisTime, -reorgLateBlockCountAttestations, params.BeaconConfig().SecondsPerSlot)
 		for {
 			select {
 			case <-s.ctx.Done():
 				return
+			case <-pat.C():
+				s.ForkChoicer().Lock()
+				s.UpdateHead(s.ctx, s.CurrentSlot()+1)
+				s.ForkChoicer().Unlock()
 			case <-st.C():
+				s.ForkChoicer().Lock()
 				if err := s.ForkChoicer().NewSlot(s.ctx, s.CurrentSlot()); err != nil {
-					log.WithError(err).Error("Could not process new slot")
+					log.WithError(err).Error("could not process new slot")
 				}

-				if err := s.UpdateHead(s.ctx); err != nil {
-					log.WithError(err).Error("Could not process attestations and update head")
-				}
+				s.UpdateHead(s.ctx, s.CurrentSlot())
+				s.ForkChoicer().Unlock()
 			}
 		}
 	}()
 }

 // UpdateHead updates the canonical head of the chain based on information from fork-choice attestations and votes.
-// It requires no external inputs.
-func (s *Service) UpdateHead(ctx context.Context) error {
-	// Only one process can process attestations and update head at a time.
-	s.processAttestationsLock.Lock()
-	defer s.processAttestationsLock.Unlock()
-
+// The caller of this function MUST hold a lock in forkchoice
+func (s *Service) UpdateHead(ctx context.Context, proposingSlot primitives.Slot) {
 	start := time.Now()
-	s.processAttestations(ctx)
+	// Only update head once per slot at the beginning of the slot
+	s.headLock.RLock()
+	lastTick := s.lastTick()
+	s.headLock.RUnlock()
+	if lastTick >= proposingSlot && proposingSlot == s.CurrentSlot() {
+		return
+	}
+
+	// This function is only called at 10 seconds or 0 seconds into the slot
+	disparity := params.BeaconNetworkConfig().MaximumGossipClockDisparity
+	if !features.Get().DisableReorgLateBlocks {
+		disparity += reorgLateBlockCountAttestations
+	}
+	s.processAttestations(ctx, disparity)
 	processAttsElapsedTime.Observe(float64(time.Since(start).Milliseconds()))

-	justified := s.ForkChoicer().JustifiedCheckpoint()
-	balances, err := s.justifiedBalances.get(ctx, justified.Root)
-	if err != nil {
-		return err
-	}
+	s.headLock.Lock()
+	s.head.lastTick = proposingSlot
+	s.headLock.Unlock()
+
 	start = time.Now()
-	newHeadRoot, err := s.cfg.ForkChoiceStore.Head(ctx, balances)
+	newHeadRoot, err := s.cfg.ForkChoiceStore.Head(ctx)
 	if err != nil {
 		log.WithError(err).Error("Could not compute head from new attestations")
 	}
@@ -163,60 +155,20 @@ func (s *Service) UpdateHead(ctx context.Context) error {
 		}).Debug("Head changed due to attestations")
 	}
 	s.headLock.RUnlock()
-	if err := s.notifyEngineIfChangedHead(ctx, newHeadRoot); err != nil {
-		return err
+	if err := s.forkchoiceUpdateWithExecution(s.ctx, newHeadRoot, proposingSlot); err != nil {
+		log.WithError(err).Error("could not update forkchoice")
 	}
-	return nil
-}
-
-// This calls notify Forkchoice Update in the event that the head has changed
-func (s *Service) notifyEngineIfChangedHead(ctx context.Context, newHeadRoot [32]byte) error {
-	s.headLock.RLock()
-	if newHeadRoot == [32]byte{} || s.headRoot() == newHeadRoot {
-		s.headLock.RUnlock()
-		return nil
-	}
-	s.headLock.RUnlock()
-
-	if !s.hasBlockInInitSyncOrDB(ctx, newHeadRoot) {
-		log.Debug("New head does not exist in DB. Do nothing")
-		return nil // We don't have the block, don't notify the engine and update head.
-	}
-
-	newHeadBlock, err := s.getBlock(ctx, newHeadRoot)
-	if err != nil {
-		log.WithError(err).Error("Could not get new head block")
-		return nil
-	}
-	headState, err := s.cfg.StateGen.StateByRoot(ctx, newHeadRoot)
-	if err != nil {
-		log.WithError(err).Error("Could not get state from db")
-		return nil
-	}
-	arg := &notifyForkchoiceUpdateArg{
-		headState: headState,
-		headRoot:  newHeadRoot,
-		headBlock: newHeadBlock.Block(),
-	}
-	_, err = s.notifyForkchoiceUpdate(s.ctx, arg)
-	if err != nil {
-		return err
-	}
-	if err := s.saveHead(ctx, newHeadRoot, newHeadBlock, headState); err != nil {
-		log.WithError(err).Error("could not save head")
-	}
-	return nil
 }

 // This processes fork choice attestations from the pool to account for validator votes and fork choice.
-func (s *Service) processAttestations(ctx context.Context) {
+func (s *Service) processAttestations(ctx context.Context, disparity time.Duration) {
 	atts := s.cfg.AttPool.ForkchoiceAttestations()
 	for _, a := range atts {
 		// Based on the spec, don't process the attestation until the subsequent slot.
 		// This delays consideration in the fork choice until their slot is in the past.
 		// https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/fork-choice.md#validate_on_attestation
 		nextSlot := a.Data.Slot + 1
-		if err := slots.VerifyTime(uint64(s.genesisTime.Unix()), nextSlot, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
+		if err := slots.VerifyTime(uint64(s.genesisTime.Unix()), nextSlot, disparity); err != nil {
 			continue
 		}

@@ -234,7 +186,7 @@ func (s *Service) processAttestations(ctx context.Context) {
 			continue
 		}

-		if err := s.receiveAttestationNoPubsub(ctx, a); err != nil {
+		if err := s.receiveAttestationNoPubsub(ctx, a, disparity); err != nil {
 			log.WithFields(logrus.Fields{
 				"slot":             a.Data.Slot,
 				"committeeIndex":   a.Data.CommitteeIndex,
@@ -251,11 +203,11 @@ func (s *Service) processAttestations(ctx context.Context) {
 //  1. Validate attestation, update validator's latest vote
 //  2. Apply fork choice to the processed attestation
 //  3. Save latest head info
-func (s *Service) receiveAttestationNoPubsub(ctx context.Context, att *ethpb.Attestation) error {
+func (s *Service) receiveAttestationNoPubsub(ctx context.Context, att *ethpb.Attestation, disparity time.Duration) error {
 	ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.receiveAttestationNoPubsub")
 	defer span.End()

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

--- a/beacon-chain/blockchain/receive_attestation_test.go
+++ b/beacon-chain/blockchain/receive_attestation_test.go
@@ -5,15 +5,16 @@ import (
 	"testing"
 	"time"

-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/transition"
 	testDB "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/attestations"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
@@ -35,7 +36,7 @@ func TestAttestationCheckPtState_FarFutureSlot(t *testing.T) {
 	chainService := setupBeaconChain(t, beaconDB)
 	chainService.genesisTime = time.Now()

-	e := types.Epoch(slots.MaxSlotBuffer/uint64(params.BeaconConfig().SlotsPerEpoch) + 1)
+	e := primitives.Epoch(slots.MaxSlotBuffer/uint64(params.BeaconConfig().SlotsPerEpoch) + 1)
 	_, err := chainService.AttestationTargetState(context.Background(), &ethpb.Checkpoint{Epoch: e})
 	require.ErrorContains(t, "exceeds max allowed value relative to the local clock", err)
 }
@@ -119,99 +120,32 @@ func TestProcessAttestations_Ok(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
 	require.NoError(t, service.cfg.AttPool.SaveForkchoiceAttestations(atts))
-	service.processAttestations(ctx)
+	service.processAttestations(ctx, 0)
 	require.Equal(t, 0, len(service.cfg.AttPool.ForkchoiceAttestations()))
 	require.LogsDoNotContain(t, hook, "Could not process attestation for fork choice")
 }

-func TestNotifyEngineIfChangedHead(t *testing.T) {
-	hook := logTest.NewGlobal()
-	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
-
-	service, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	service.cfg.ProposerSlotIndexCache = cache.NewProposerPayloadIDsCache()
-	require.NoError(t, service.notifyEngineIfChangedHead(ctx, service.headRoot()))
-	hookErr := "could not notify forkchoice update"
-	invalidStateErr := "Could not get state from db"
-	require.LogsDoNotContain(t, hook, invalidStateErr)
-	require.LogsDoNotContain(t, hook, hookErr)
-	gb, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlock())
-	require.NoError(t, err)
-	require.NoError(t, service.saveInitSyncBlock(ctx, [32]byte{'a'}, gb))
-	require.NoError(t, service.notifyEngineIfChangedHead(ctx, [32]byte{'a'}))
-	require.LogsContain(t, hook, invalidStateErr)
-
-	hook.Reset()
-	service.head = &head{
-		root:  [32]byte{'a'},
-		block: nil, /* should not panic if notify head uses correct head */
-	}
-
-	// Block in Cache
-	b := util.NewBeaconBlock()
-	b.Block.Slot = 2
-	wsb, err := blocks.NewSignedBeaconBlock(b)
-	require.NoError(t, err)
-	r1, err := b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	require.NoError(t, service.saveInitSyncBlock(ctx, r1, wsb))
-	st, _ := util.DeterministicGenesisState(t, 1)
-	service.head = &head{
-		slot:  1,
-		root:  r1,
-		block: wsb,
-		state: st,
-	}
-	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(2, 1, [8]byte{1}, [32]byte{2})
-	require.NoError(t, service.notifyEngineIfChangedHead(ctx, r1))
-	require.LogsDoNotContain(t, hook, invalidStateErr)
-	require.LogsDoNotContain(t, hook, hookErr)
-
-	// Block in DB
-	b = util.NewBeaconBlock()
-	b.Block.Slot = 3
-	util.SaveBlock(t, ctx, service.cfg.BeaconDB, b)
-	r1, err = b.Block.HashTreeRoot()
-	require.NoError(t, err)
-	st, _ = util.DeterministicGenesisState(t, 1)
-	service.head = &head{
-		slot:  1,
-		root:  r1,
-		block: wsb,
-		state: st,
-	}
-	service.cfg.ProposerSlotIndexCache.SetProposerAndPayloadIDs(2, 1, [8]byte{1}, [32]byte{2})
-	require.NoError(t, service.notifyEngineIfChangedHead(ctx, r1))
-	require.LogsDoNotContain(t, hook, invalidStateErr)
-	require.LogsDoNotContain(t, hook, hookErr)
-	vId, payloadID, has := service.cfg.ProposerSlotIndexCache.GetProposerPayloadIDs(2, [32]byte{2})
-	require.Equal(t, true, has)
-	require.Equal(t, types.ValidatorIndex(1), vId)
-	require.Equal(t, [8]byte{1}, payloadID)
-
-	// Test zero headRoot returns immediately.
-	headRoot := service.headRoot()
-	require.NoError(t, service.notifyEngineIfChangedHead(ctx, [32]byte{}))
-	require.Equal(t, service.headRoot(), headRoot)
-}
-
 func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
 	ctx := context.Background()
-	opts := testServiceOptsWithDB(t)
+	beaconDB := testDB.SetupDB(t)
 	fcs := doublylinkedtree.New()
-	opts = append(opts,
+	newStateGen := stategen.New(beaconDB, fcs)
+	fcs.SetBalancesByRooter(newStateGen.ActiveNonSlashedBalancesByRoot)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(newStateGen),
 		WithAttestationPool(attestations.NewPool()),
 		WithStateNotifier(&mockBeaconNode{}),
 		WithForkChoiceStore(fcs),
-	)
+	}

 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)
 	service.genesisTime = prysmTime.Now().Add(-2 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)
 	genesisState, pks := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, genesisState))
+	ojc := &ethpb.Checkpoint{Epoch: 0, Root: service.originBlockRoot[:]}
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{Epoch: 0, Root: service.originBlockRoot}))
 	copied := genesisState.Copy()
 	// Generate a new block for attesters to attest
 	blk, err := util.GenerateFullBlock(copied, pks, util.DefaultBlockGenConfig(), 1)
@@ -232,9 +166,10 @@ func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
 	require.NoError(t, service.cfg.AttPool.SaveForkchoiceAttestations(atts))
 	// Verify the target is in forkchoice
 	require.Equal(t, true, fcs.HasNode(bytesutil.ToBytes32(atts[0].Data.BeaconBlockRoot)))
+	require.Equal(t, tRoot, bytesutil.ToBytes32(atts[0].Data.BeaconBlockRoot))
+	require.Equal(t, true, fcs.HasNode(service.originBlockRoot))

 	// Insert a new block to forkchoice
-	ojc := &ethpb.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash[:]}
 	b, err := util.GenerateFullBlock(genesisState, pks, util.DefaultBlockGenConfig(), 2)
 	require.NoError(t, err)
 	b.Block.ParentRoot = service.originBlockRoot[:]
@@ -248,27 +183,31 @@ func TestService_ProcessAttestationsAndUpdateHead(t *testing.T) {
 	service.head.root = r // Old head

 	require.Equal(t, 1, len(service.cfg.AttPool.ForkchoiceAttestations()))
-	require.NoError(t, err, service.UpdateHead(ctx))
-
+	service.UpdateHead(ctx, 0)
+	require.Equal(t, tRoot, service.headRoot())
 	require.Equal(t, 0, len(service.cfg.AttPool.ForkchoiceAttestations())) // Validate att pool is empty
-	require.Equal(t, tRoot, service.head.root)                             // Validate head is the new one
 }

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

 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)
 	service.genesisTime = prysmTime.Now().Add(-2 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)
 	genesisState, pks := util.DeterministicGenesisState(t, 64)
 	require.NoError(t, service.saveGenesisData(ctx, genesisState))
+	require.NoError(t, fcs.UpdateJustifiedCheckpoint(ctx, &forkchoicetypes.Checkpoint{Epoch: 0, Root: service.originBlockRoot}))
 	copied := genesisState.Copy()
 	// Generate a new block
 	blk, err := util.GenerateFullBlock(copied, pks, util.DefaultBlockGenConfig(), 1)
@@ -296,9 +235,8 @@ func TestService_UpdateHead_NoAtts(t *testing.T) {
 	require.Equal(t, 3, fcs.NodeCount())

 	require.Equal(t, 0, service.cfg.AttPool.ForkchoiceAttestationCount())
-	require.NoError(t, err, service.UpdateHead(ctx))
+	service.UpdateHead(ctx, 0)
+	require.Equal(t, r, service.headRoot())

 	require.Equal(t, 0, len(service.cfg.AttPool.ForkchoiceAttestations())) // Validate att pool is empty
-	require.Equal(t, r, service.head.root)                                 // Validate head is the new one
-
 }
--- a/beacon-chain/blockchain/receive_block.go
+++ b/beacon-chain/blockchain/receive_block.go
@@ -7,21 +7,23 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/v3/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v3/monitoring/tracing"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/runtime/version"
 	"github.com/prysmaticlabs/prysm/v3/time"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
 	"go.opencensus.io/trace"
 )

 // This defines how many epochs since finality the run time will begin to save hot state on to the DB.
-var epochsSinceFinalitySaveHotStateDB = types.Epoch(100)
+var epochsSinceFinalitySaveHotStateDB = primitives.Epoch(100)

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

@@ -32,10 +34,10 @@ type SlashingReceiver interface {

 // ReceiveBlock is a function that defines the operations (minus pubsub)
 // that are performed on a received block. The operations consist of:
-//   1. Validate block, apply state transition and update checkpoints
-//   2. Apply fork choice to the processed block
-//   3. Save latest head info
-func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.SignedBeaconBlock, blockRoot [32]byte) error {
+//  1. Validate block, apply state transition and update checkpoints
+//  2. Apply fork choice to the processed block
+//  3. Save latest head info
+func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlock")
 	defer span.End()
 	receivedTime := time.Now()
@@ -44,6 +46,9 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.SignedBeaco
 		return err
 	}

+	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 {
 		err := errors.Wrap(err, "could not process block")
@@ -62,11 +67,13 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.SignedBeaco
 	}

 	// Reports on block and fork choice metrics.
-	finalized := s.FinalizedCheckpt()
+	cp := s.ForkChoicer().FinalizedCheckpoint()
+	finalized := &ethpb.Checkpoint{Epoch: cp.Epoch, Root: bytesutil.SafeCopyBytes(cp.Root[:])}
 	reportSlotMetrics(blockCopy.Block().Slot(), s.HeadSlot(), s.CurrentSlot(), finalized)

 	// Log block sync status.
-	justified := s.CurrentJustifiedCheckpt()
+	cp = s.ForkChoicer().JustifiedCheckpoint()
+	justified := &ethpb.Checkpoint{Epoch: cp.Epoch, Root: bytesutil.SafeCopyBytes(cp.Root[:])}
 	if err := logBlockSyncStatus(blockCopy.Block(), blockRoot, justified, finalized, receivedTime, uint64(s.genesisTime.Unix())); err != nil {
 		log.WithError(err).Error("Unable to log block sync status")
 	}
@@ -85,10 +92,13 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.SignedBeaco
 // ReceiveBlockBatch processes the whole block batch at once, assuming the block batch is linear ,transitioning
 // the state, performing batch verification of all collected signatures and then performing the appropriate
 // actions for a block post-transition.
-func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []interfaces.SignedBeaconBlock, blkRoots [][32]byte) error {
+func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []interfaces.ReadOnlySignedBeaconBlock, blkRoots [][32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlockBatch")
 	defer span.End()

+	s.cfg.ForkChoiceStore.Lock()
+	defer s.cfg.ForkChoiceStore.Unlock()
+
 	// Apply state transition on the incoming newly received block batches, one by one.
 	if err := s.onBlockBatch(ctx, blocks, blkRoots); err != nil {
 		err := errors.Wrap(err, "could not process block in batch")
@@ -113,14 +123,15 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []interfaces.Sig
 		})

 		// Reports on blockCopy and fork choice metrics.
-		finalized := s.FinalizedCheckpt()
+		cp := s.ForkChoicer().FinalizedCheckpoint()
+		finalized := &ethpb.Checkpoint{Epoch: cp.Epoch, Root: bytesutil.SafeCopyBytes(cp.Root[:])}
 		reportSlotMetrics(blockCopy.Block().Slot(), s.HeadSlot(), s.CurrentSlot(), finalized)
 	}

 	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
 		return err
 	}
-	finalized := s.FinalizedCheckpt()
+	finalized := s.ForkChoicer().FinalizedCheckpoint()
 	if finalized == nil {
 		return errNilFinalizedInStore
 	}
@@ -141,20 +152,22 @@ func (s *Service) HasBlock(ctx context.Context, root [32]byte) bool {

 // ReceiveAttesterSlashing receives an attester slashing and inserts it to forkchoice
 func (s *Service) ReceiveAttesterSlashing(ctx context.Context, slashing *ethpb.AttesterSlashing) {
+	s.ForkChoicer().Lock()
+	defer s.ForkChoicer().Unlock()
 	s.InsertSlashingsToForkChoiceStore(ctx, []*ethpb.AttesterSlashing{slashing})
 }

-func (s *Service) handlePostBlockOperations(b interfaces.BeaconBlock) error {
-	// Delete the processed block attestations from attestation pool.
-	if err := s.deletePoolAtts(b.Body().Attestations()); err != nil {
-		return err
-	}
-
+func (s *Service) handlePostBlockOperations(b interfaces.ReadOnlyBeaconBlock) error {
 	// Mark block exits as seen so we don't include same ones in future blocks.
 	for _, e := range b.Body().VoluntaryExits() {
 		s.cfg.ExitPool.MarkIncluded(e)
 	}

+	// Mark block BLS changes as seen so we don't include same ones in future blocks.
+	if err := s.handleBlockBLSToExecChanges(b); err != nil {
+		return errors.Wrap(err, "could not process BLSToExecutionChanges")
+	}
+
 	//  Mark attester slashings as seen so we don't include same ones in future blocks.
 	for _, as := range b.Body().AttesterSlashings() {
 		s.cfg.SlashingPool.MarkIncludedAttesterSlashing(as)
@@ -162,13 +175,28 @@ func (s *Service) handlePostBlockOperations(b interfaces.BeaconBlock) error {
 	return nil
 }

+func (s *Service) handleBlockBLSToExecChanges(blk interfaces.ReadOnlyBeaconBlock) error {
+	if blk.Version() < version.Capella {
+		return nil
+	}
+	changes, err := blk.Body().BLSToExecutionChanges()
+	if err != nil {
+		return errors.Wrap(err, "could not get BLSToExecutionChanges")
+	}
+	for _, change := range changes {
+		s.cfg.BLSToExecPool.MarkIncluded(change)
+	}
+	return nil
+}
+
 // This checks whether it's time to start saving hot state to DB.
 // It's time when there's `epochsSinceFinalitySaveHotStateDB` epochs of non-finality.
+// Requires a read lock on forkchoice
 func (s *Service) checkSaveHotStateDB(ctx context.Context) error {
 	currentEpoch := slots.ToEpoch(s.CurrentSlot())
 	// Prevent `sinceFinality` going underflow.
-	var sinceFinality types.Epoch
-	finalized := s.FinalizedCheckpt()
+	var sinceFinality primitives.Epoch
+	finalized := s.ForkChoicer().FinalizedCheckpoint()
 	if finalized == nil {
 		return errNilFinalizedInStore
 	}
--- a/beacon-chain/blockchain/receive_block_test.go
+++ b/beacon-chain/blockchain/receive_block_test.go
@@ -10,12 +10,13 @@ import (
 	testDB "github.com/prysmaticlabs/prysm/v3/beacon-chain/db/testing"
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/attestations"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/blstoexec"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/assert"
@@ -28,12 +29,12 @@ func TestService_ReceiveBlock(t *testing.T) {
 	ctx := context.Background()

 	genesis, keys := util.DeterministicGenesisState(t, 64)
-	genFullBlock := func(t *testing.T, conf *util.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
+	genFullBlock := func(t *testing.T, conf *util.BlockGenConfig, slot primitives.Slot) *ethpb.SignedBeaconBlock {
 		blk, err := util.GenerateFullBlock(genesis, keys, conf, slot)
 		assert.NoError(t, err)
 		return blk
 	}
-	params.SetupTestConfigCleanupWithLock(t)
+	//params.SetupTestConfigCleanupWithLock(t)
 	bc := params.BeaconConfig().Copy()
 	bc.ShardCommitteePeriod = 0 // Required for voluntary exits test in reasonable time.
 	params.OverrideBeaconConfig(bc)
@@ -96,7 +97,8 @@ func TestService_ReceiveBlock(t *testing.T) {
 				),
 			},
 			check: func(t *testing.T, s *Service) {
-				pending := s.cfg.ExitPool.PendingExits(genesis, 1, true /* no limit */)
+				pending, err := s.cfg.ExitPool.PendingExits()
+				require.NoError(t, err)
 				if len(pending) != 0 {
 					t.Errorf(
 						"Did not mark the correct number of exits. Got %d pending but wanted %d",
@@ -204,7 +206,7 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 	ctx := context.Background()

 	genesis, keys := util.DeterministicGenesisState(t, 64)
-	genFullBlock := func(t *testing.T, conf *util.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
+	genFullBlock := func(t *testing.T, conf *util.BlockGenConfig, slot primitives.Slot) *ethpb.SignedBeaconBlock {
 		blk, err := util.GenerateFullBlock(genesis, keys, conf, slot)
 		assert.NoError(t, err)
 		return blk
@@ -225,8 +227,8 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 				block: genFullBlock(t, util.DefaultBlockGenConfig(), 2 /*slot*/),
 			},
 			check: func(t *testing.T, s *Service) {
-				assert.Equal(t, types.Slot(2), s.head.state.Slot(), "Incorrect head state slot")
-				assert.Equal(t, types.Slot(2), s.head.block.Block().Slot(), "Incorrect head block slot")
+				assert.Equal(t, primitives.Slot(2), s.head.state.Slot(), "Incorrect head state slot")
+				assert.Equal(t, primitives.Slot(2), s.head.block.Block().Slot(), "Incorrect head block slot")
 			},
 		},
 		{
@@ -260,7 +262,7 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 			require.NoError(t, err)
 			wsb, err := blocks.NewSignedBeaconBlock(tt.args.block)
 			require.NoError(t, err)
-			blks := []interfaces.SignedBeaconBlock{wsb}
+			blks := []interfaces.ReadOnlySignedBeaconBlock{wsb}
 			roots := [][32]byte{root}
 			err = s.ReceiveBlockBatch(ctx, blks, roots)
 			if tt.wantedErr != "" {
@@ -332,3 +334,62 @@ func TestCheckSaveHotStateDB_Overflow(t *testing.T) {
 	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
 	assert.LogsDoNotContain(t, hook, "Entering mode to save hot states in DB")
 }
+
+func TestHandleBlockBLSToExecutionChanges(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	fc := doublylinkedtree.New()
+	pool := blstoexec.NewPool()
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB, fc)),
+		WithForkChoiceStore(fc),
+		WithStateNotifier(&blockchainTesting.MockStateNotifier{}),
+		WithBLSToExecPool(pool),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+
+	t.Run("pre Capella block", func(t *testing.T) {
+		body := &ethpb.BeaconBlockBodyBellatrix{}
+		pbb := &ethpb.BeaconBlockBellatrix{
+			Body: body,
+		}
+		blk, err := blocks.NewBeaconBlock(pbb)
+		require.NoError(t, err)
+		require.NoError(t, service.handleBlockBLSToExecChanges(blk))
+	})
+
+	t.Run("Post Capella no changes", func(t *testing.T) {
+		body := &ethpb.BeaconBlockBodyCapella{}
+		pbb := &ethpb.BeaconBlockCapella{
+			Body: body,
+		}
+		blk, err := blocks.NewBeaconBlock(pbb)
+		require.NoError(t, err)
+		require.NoError(t, service.handleBlockBLSToExecChanges(blk))
+	})
+
+	t.Run("Post Capella some changes", func(t *testing.T) {
+		idx := primitives.ValidatorIndex(123)
+		change := &ethpb.BLSToExecutionChange{
+			ValidatorIndex: idx,
+		}
+		signedChange := &ethpb.SignedBLSToExecutionChange{
+			Message: change,
+		}
+		body := &ethpb.BeaconBlockBodyCapella{
+			BlsToExecutionChanges: []*ethpb.SignedBLSToExecutionChange{signedChange},
+		}
+		pbb := &ethpb.BeaconBlockCapella{
+			Body: body,
+		}
+		blk, err := blocks.NewBeaconBlock(pbb)
+		require.NoError(t, err)
+
+		pool.InsertBLSToExecChange(signedChange)
+		require.Equal(t, true, pool.ValidatorExists(idx))
+		require.NoError(t, service.handleBlockBLSToExecChanges(blk))
+		require.Equal(t, false, pool.ValidatorExists(idx))
+	})
+}
--- a/beacon-chain/blockchain/service.go
+++ b/beacon-chain/blockchain/service.go
@@ -23,6 +23,7 @@ import (
 	f "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/attestations"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/blstoexec"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/slashings"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/p2p"
@@ -32,7 +33,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	prysmTime "github.com/prysmaticlabs/prysm/v3/time"
@@ -43,21 +44,19 @@ 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   types.Slot
-	boundaryRoots           [][32]byte
-	checkpointStateCache    *cache.CheckpointStateCache
-	initSyncBlocks          map[[32]byte]interfaces.SignedBeaconBlock
-	initSyncBlocksLock      sync.RWMutex
-	justifiedBalances       *stateBalanceCache
-	wsVerifier              *WeakSubjectivityVerifier
-	processAttestationsLock sync.Mutex
+	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
 }

 // config options for the service.
@@ -70,6 +69,7 @@ type config struct {
 	AttPool                 attestations.Pool
 	ExitPool                voluntaryexits.PoolManager
 	SlashingPool            slashings.PoolManager
+	BLSToExecPool           blstoexec.PoolManager
 	P2p                     p2p.Broadcaster
 	MaxRoutines             int
 	StateNotifier           statefeed.Notifier
@@ -92,8 +92,8 @@ func NewService(ctx context.Context, opts ...Option) (*Service, error) {
 		cancel:               cancel,
 		boundaryRoots:        [][32]byte{},
 		checkpointStateCache: cache.NewCheckpointStateCache(),
-		initSyncBlocks:       make(map[[32]byte]interfaces.SignedBeaconBlock),
-		cfg:                  &config{},
+		initSyncBlocks:       make(map[[32]byte]interfaces.ReadOnlySignedBeaconBlock),
+		cfg:                  &config{ProposerSlotIndexCache: cache.NewProposerPayloadIDsCache()},
 	}
 	for _, opt := range opts {
 		if err := opt(srv); err != nil {
@@ -101,12 +101,6 @@ func NewService(ctx context.Context, opts ...Option) (*Service, error) {
 		}
 	}
 	var err error
-	if srv.justifiedBalances == nil {
-		srv.justifiedBalances, err = newStateBalanceCache(srv.cfg.StateGen)
-		if err != nil {
-			return nil, err
-		}
-	}
 	srv.wsVerifier, err = NewWeakSubjectivityVerifier(srv.cfg.WeakSubjectivityCheckpt, srv.cfg.BeaconDB)
 	if err != nil {
 		return nil, err
@@ -205,7 +199,9 @@ func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 	}

 	fRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
-	if err := s.cfg.ForkChoiceStore.UpdateJustifiedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: justified.Epoch,
+	s.cfg.ForkChoiceStore.Lock()
+	defer s.cfg.ForkChoiceStore.Unlock()
+	if err := s.cfg.ForkChoiceStore.UpdateJustifiedCheckpoint(s.ctx, &forkchoicetypes.Checkpoint{Epoch: justified.Epoch,
 		Root: bytesutil.ToBytes32(justified.Root)}); err != nil {
 		return errors.Wrap(err, "could not update forkchoice's justified checkpoint")
 	}
@@ -431,6 +427,8 @@ func (s *Service) saveGenesisData(ctx context.Context, genesisState state.Beacon
 	s.originBlockRoot = genesisBlkRoot
 	s.cfg.StateGen.SaveFinalizedState(0 /*slot*/, genesisBlkRoot, genesisState)

+	s.cfg.ForkChoiceStore.Lock()
+	defer s.cfg.ForkChoiceStore.Unlock()
 	if err := s.cfg.ForkChoiceStore.InsertNode(ctx, genesisState, genesisBlkRoot); err != nil {
 		log.WithError(err).Fatal("Could not process genesis block for fork choice")
 	}
@@ -451,6 +449,7 @@ func (s *Service) saveGenesisData(ctx context.Context, genesisState state.Beacon
 // 1.) Check fork choice store.
 // 2.) Check DB.
 // Checking 1.) is ten times faster than checking 2.)
+// this function requires a lock in forkchoice
 func (s *Service) hasBlock(ctx context.Context, root [32]byte) bool {
 	if s.cfg.ForkChoiceStore.HasNode(root) {
 		return true
--- a/beacon-chain/blockchain/service_test.go
+++ b/beacon-chain/blockchain/service_test.go
@@ -10,6 +10,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/prysmaticlabs/prysm/v3/async/event"
 	mock "github.com/prysmaticlabs/prysm/v3/beacon-chain/blockchain/testing"
+	"github.com/prysmaticlabs/prysm/v3/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/cache/depositcache"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/feed"
@@ -71,6 +72,9 @@ func (mb *mockBroadcaster) BroadcastSyncCommitteeMessage(_ context.Context, _ ui
 	return nil
 }

+func (mb *mockBroadcaster) BroadcastBLSChanges(_ context.Context, _ []*ethpb.SignedBLSToExecutionChange) {
+}
+
 var _ p2p.Broadcaster = (*mockBroadcaster)(nil)

 func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
@@ -132,6 +136,7 @@ func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 		WithForkChoiceStore(fc),
 		WithAttestationService(attService),
 		WithStateGen(stateGen),
+		WithProposerIdsCache(cache.NewProposerPayloadIDsCache()),
 	}

 	chainService, err := NewService(ctx, opts...)
@@ -438,7 +443,7 @@ func TestServiceStop_SaveCachedBlocks(t *testing.T) {
 		cfg:            &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB, doublylinkedtree.New())},
 		ctx:            ctx,
 		cancel:         cancel,
-		initSyncBlocks: make(map[[32]byte]interfaces.SignedBeaconBlock),
+		initSyncBlocks: make(map[[32]byte]interfaces.ReadOnlySignedBeaconBlock),
 	}
 	bb := util.NewBeaconBlock()
 	r, err := bb.Block.HashTreeRoot()
--- a/beacon-chain/blockchain/state_balance_cache.go
+++ b/beacon-chain/blockchain/state_balance_cache.go
@@ -1,81 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"errors"
-	"sync"
-
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/core/time"
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state/stategen"
-)
-
-type stateBalanceCache struct {
-	sync.Mutex
-	balances []uint64
-	root     [32]byte
-	stateGen stateByRooter
-}
-
-type stateByRooter interface {
-	StateByRoot(context.Context, [32]byte) (state.BeaconState, error)
-}
-
-// newStateBalanceCache exists to remind us that stateBalanceCache needs a state gen
-// to avoid nil pointer bugs when updating the cache in the read path (get())
-func newStateBalanceCache(sg *stategen.State) (*stateBalanceCache, error) {
-	if sg == nil {
-		return nil, errors.New("can't initialize state balance cache without stategen")
-	}
-	return &stateBalanceCache{stateGen: sg}, nil
-}
-
-// update is called by get() when the requested root doesn't match
-// the previously read value. This cache assumes we only want to cache one
-// set of balances for a single root (the current justified root).
-//
-// WARNING: this is not thread-safe on its own, relies on get() for locking
-func (c *stateBalanceCache) update(ctx context.Context, justifiedRoot [32]byte) ([]uint64, error) {
-	stateBalanceCacheMiss.Inc()
-	justifiedState, err := c.stateGen.StateByRoot(ctx, justifiedRoot)
-	if err != nil {
-		return nil, err
-	}
-	if justifiedState == nil || justifiedState.IsNil() {
-		return nil, errNilStateFromStategen
-	}
-	epoch := time.CurrentEpoch(justifiedState)
-
-	justifiedBalances := make([]uint64, justifiedState.NumValidators())
-	var balanceAccumulator = func(idx int, val state.ReadOnlyValidator) error {
-		if helpers.IsActiveValidatorUsingTrie(val, epoch) {
-			justifiedBalances[idx] = val.EffectiveBalance()
-		} else {
-			justifiedBalances[idx] = 0
-		}
-		return nil
-	}
-	if err := justifiedState.ReadFromEveryValidator(balanceAccumulator); err != nil {
-		return nil, err
-	}
-
-	c.balances = justifiedBalances
-	c.root = justifiedRoot
-	return c.balances, nil
-}
-
-// getBalances takes an explicit justifiedRoot so it can invalidate the singleton cache key
-// when the justified root changes, and takes a context so that the long-running stategen
-// read path can connect to the upstream cancellation/timeout chain.
-func (c *stateBalanceCache) get(ctx context.Context, justifiedRoot [32]byte) ([]uint64, error) {
-	c.Lock()
-	defer c.Unlock()
-
-	if justifiedRoot != [32]byte{} && justifiedRoot == c.root {
-		stateBalanceCacheHit.Inc()
-		return c.balances, nil
-	}
-
-	return c.update(ctx, justifiedRoot)
-}
--- a/beacon-chain/blockchain/state_balance_cache_test.go
+++ b/beacon-chain/blockchain/state_balance_cache_test.go
@@ -1,227 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"encoding/binary"
-	"errors"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
-	state_native "github.com/prysmaticlabs/prysm/v3/beacon-chain/state/state-native"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v3/testing/require"
-	"github.com/prysmaticlabs/prysm/v3/time/slots"
-)
-
-type testStateOpt func(*ethpb.BeaconStateAltair)
-
-func testStateWithValidators(v []*ethpb.Validator) testStateOpt {
-	return func(a *ethpb.BeaconStateAltair) {
-		a.Validators = v
-	}
-}
-
-func testStateWithSlot(slot types.Slot) testStateOpt {
-	return func(a *ethpb.BeaconStateAltair) {
-		a.Slot = slot
-	}
-}
-
-func testStateFixture(opts ...testStateOpt) state.BeaconState {
-	a := &ethpb.BeaconStateAltair{}
-	for _, o := range opts {
-		o(a)
-	}
-	s, _ := state_native.InitializeFromProtoUnsafeAltair(a)
-	return s
-}
-
-func generateTestValidators(count int, opts ...func(*ethpb.Validator)) []*ethpb.Validator {
-	vs := make([]*ethpb.Validator, count)
-	var i uint32 = 0
-	for ; i < uint32(count); i++ {
-		pk := make([]byte, 48)
-		binary.LittleEndian.PutUint32(pk, i)
-		v := &ethpb.Validator{PublicKey: pk}
-		for _, o := range opts {
-			o(v)
-		}
-		vs[i] = v
-	}
-	return vs
-}
-
-func oddValidatorsExpired(currentSlot types.Slot) func(*ethpb.Validator) {
-	return func(v *ethpb.Validator) {
-		pki := binary.LittleEndian.Uint64(v.PublicKey)
-		if pki%2 == 0 {
-			v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-		} else {
-			v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) - 1)
-		}
-	}
-}
-
-func oddValidatorsQueued(currentSlot types.Slot) func(*ethpb.Validator) {
-	return func(v *ethpb.Validator) {
-		v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-		pki := binary.LittleEndian.Uint64(v.PublicKey)
-		if pki%2 == 0 {
-			v.ActivationEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) - 1)
-		} else {
-			v.ActivationEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-		}
-	}
-}
-
-func allValidatorsValid(currentSlot types.Slot) func(*ethpb.Validator) {
-	return func(v *ethpb.Validator) {
-		v.ActivationEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) - 1)
-		v.ExitEpoch = types.Epoch(int(slots.ToEpoch(currentSlot)) + 1)
-	}
-}
-
-func balanceIsKeyTimes2(v *ethpb.Validator) {
-	pki := binary.LittleEndian.Uint64(v.PublicKey)
-	v.EffectiveBalance = uint64(pki) * 2
-}
-
-func testHalfExpiredValidators() ([]*ethpb.Validator, []uint64) {
-	balances := []uint64{0, 0, 4, 0, 8, 0, 12, 0, 16, 0}
-	return generateTestValidators(10,
-		oddValidatorsExpired(types.Slot(99)),
-		balanceIsKeyTimes2), balances
-}
-
-func testHalfQueuedValidators() ([]*ethpb.Validator, []uint64) {
-	balances := []uint64{0, 0, 4, 0, 8, 0, 12, 0, 16, 0}
-	return generateTestValidators(10,
-		oddValidatorsQueued(types.Slot(99)),
-		balanceIsKeyTimes2), balances
-}
-
-func testAllValidValidators() ([]*ethpb.Validator, []uint64) {
-	balances := []uint64{0, 2, 4, 6, 8, 10, 12, 14, 16, 18}
-	return generateTestValidators(10,
-		allValidatorsValid(types.Slot(99)),
-		balanceIsKeyTimes2), balances
-}
-
-func TestStateBalanceCache(t *testing.T) {
-	type sbcTestCase struct {
-		err      error
-		root     [32]byte
-		sbc      *stateBalanceCache
-		balances []uint64
-		name     string
-	}
-	sentinelCacheMiss := errors.New("cache missed, as expected")
-	sentinelBalances := []uint64{1, 2, 3, 4, 5}
-	halfExpiredValidators, halfExpiredBalances := testHalfExpiredValidators()
-	halfQueuedValidators, halfQueuedBalances := testHalfQueuedValidators()
-	allValidValidators, allValidBalances := testAllValidValidators()
-	cases := []sbcTestCase{
-		{
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			balances: sentinelBalances,
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					err: sentinelCacheMiss,
-				},
-				root:     bytesutil.ToBytes32([]byte{'A'}),
-				balances: sentinelBalances,
-			},
-			name: "cache hit",
-		},
-		// this works by using a staterooter that returns a known error
-		// so really we're testing the miss by making sure stategen got called
-		// this also tells us stategen errors are propagated
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					err: sentinelCacheMiss,
-				},
-				root: bytesutil.ToBytes32([]byte{'B'}),
-			},
-			err:  sentinelCacheMiss,
-			root: bytesutil.ToBytes32([]byte{'A'}),
-			name: "cache miss",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{},
-				root:     bytesutil.ToBytes32([]byte{'B'}),
-			},
-			err:  errNilStateFromStategen,
-			root: bytesutil.ToBytes32([]byte{'A'}),
-			name: "error for nil state upon cache miss",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(halfExpiredValidators)),
-				},
-			},
-			balances: halfExpiredBalances,
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			name:     "test filtering by exit epoch",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(halfQueuedValidators)),
-				},
-			},
-			balances: halfQueuedBalances,
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			name:     "test filtering by activation epoch",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(allValidValidators)),
-				},
-			},
-			balances: allValidBalances,
-			root:     bytesutil.ToBytes32([]byte{'A'}),
-			name:     "happy path",
-		},
-		{
-			sbc: &stateBalanceCache{
-				stateGen: &mockStateByRooter{
-					state: testStateFixture(
-						testStateWithSlot(99),
-						testStateWithValidators(allValidValidators)),
-				},
-			},
-			balances: allValidBalances,
-			root:     [32]byte{},
-			name:     "zero root",
-		},
-	}
-	ctx := context.Background()
-	for _, c := range cases {
-		t.Run(c.name, func(t *testing.T) {
-			cache := c.sbc
-			cacheRootStart := cache.root
-			b, err := cache.get(ctx, c.root)
-			require.ErrorIs(t, err, c.err)
-			require.DeepEqual(t, c.balances, b)
-			if c.err != nil {
-				// if there was an error somewhere, the root should not have changed (unless it already matched)
-				require.Equal(t, cacheRootStart, cache.root)
-			} else {
-				// when successful, the cache should always end with a root matching the request
-				require.Equal(t, c.root, cache.root)
-			}
-		})
-	}
-}
--- a/beacon-chain/blockchain/testing/BUILD.bazel
+++ b/beacon-chain/blockchain/testing/BUILD.bazel
@@ -20,11 +20,13 @@ go_library(
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/forkchoice:go_default_library",
        "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/state-native:go_default_library",
        "//config/fieldparams:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//encoding/bytesutil:go_default_library",
+        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
--- a/beacon-chain/blockchain/testing/mock.go
+++ b/beacon-chain/blockchain/testing/mock.go
@@ -19,11 +19,13 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
+	state_native "github.com/prysmaticlabs/prysm/v3/beacon-chain/state/state-native"
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+	enginev1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/sirupsen/logrus"
 )
@@ -32,6 +34,7 @@ var ErrNilState = errors.New("nil state")

 // ChainService defines the mock interface for testing
 type ChainService struct {
+	NotFinalized                bool
 	Optimistic                  bool
 	ValidAttestation            bool
 	ValidatorsRoot              [32]byte
@@ -39,7 +42,7 @@ type ChainService struct {
 	FinalizedCheckPoint         *ethpb.Checkpoint
 	CurrentJustifiedCheckPoint  *ethpb.Checkpoint
 	PreviousJustifiedCheckPoint *ethpb.Checkpoint
-	Slot                        *types.Slot // Pointer because 0 is a useful value, so checking against it can be incorrect.
+	Slot                        *primitives.Slot // Pointer because 0 is a useful value, so checking against it can be incorrect.
 	Balance                     *precompute.Balance
 	CanonicalRoots              map[[32]byte]bool
 	Fork                        *ethpb.Fork
@@ -47,11 +50,11 @@ type ChainService struct {
 	InitSyncBlockRoots          map[[32]byte]bool
 	DB                          db.Database
 	State                       state.BeaconState
-	Block                       interfaces.SignedBeaconBlock
+	Block                       interfaces.ReadOnlySignedBeaconBlock
 	VerifyBlkDescendantErr      error
 	stateNotifier               statefeed.Notifier
-	BlocksReceived              []interfaces.SignedBeaconBlock
-	SyncCommitteeIndices        []types.CommitteeIndex
+	BlocksReceived              []interfaces.ReadOnlySignedBeaconBlock
+	SyncCommitteeIndices        []primitives.CommitteeIndex
 	blockNotifier               blockfeed.Notifier
 	opNotifier                  opfeed.Notifier
 	Root                        []byte
@@ -170,7 +173,7 @@ func (mon *MockOperationNotifier) OperationFeed() *event.Feed {
 }

 // ReceiveBlockInitialSync mocks ReceiveBlockInitialSync method in chain service.
-func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block interfaces.SignedBeaconBlock, _ [32]byte) error {
+func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, _ [32]byte) error {
 	if s.State == nil {
 		return ErrNilState
 	}
@@ -198,7 +201,7 @@ func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block interf
 }

 // ReceiveBlockBatch processes blocks in batches from initial-sync.
-func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []interfaces.SignedBeaconBlock, _ [][32]byte) error {
+func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []interfaces.ReadOnlySignedBeaconBlock, _ [][32]byte) error {
 	if s.State == nil {
 		return ErrNilState
 	}
@@ -228,7 +231,7 @@ func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []interfaces.
 }

 // ReceiveBlock mocks ReceiveBlock method in chain service.
-func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.SignedBeaconBlock, _ [32]byte) error {
+func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, _ [32]byte) error {
 	if s.ReceiveBlockMockErr != nil {
 		return s.ReceiveBlockMockErr
 	}
@@ -259,7 +262,7 @@ func (s *ChainService) ReceiveBlock(ctx context.Context, block interfaces.Signed
 }

 // HeadSlot mocks HeadSlot method in chain service.
-func (s *ChainService) HeadSlot() types.Slot {
+func (s *ChainService) HeadSlot() primitives.Slot {
 	if s.State == nil {
 		return 0
 	}
@@ -275,7 +278,7 @@ func (s *ChainService) HeadRoot(_ context.Context) ([]byte, error) {
 }

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

@@ -284,6 +287,11 @@ func (s *ChainService) HeadState(context.Context) (state.BeaconState, error) {
 	return s.State, nil
 }

+// HeadStateReadOnly mocks HeadStateReadOnly method in chain service.
+func (s *ChainService) HeadStateReadOnly(context.Context) (state.ReadOnlyBeaconState, error) {
+	return s.State, nil
+}
+
 // CurrentFork mocks HeadState method in chain service.
 func (s *ChainService) CurrentFork() *ethpb.Fork {
 	return s.Fork
@@ -315,9 +323,9 @@ func (s *ChainService) AttestationTargetState(_ context.Context, _ *ethpb.Checkp
 }

 // HeadValidatorsIndices mocks the same method in the chain service.
-func (s *ChainService) HeadValidatorsIndices(ctx context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error) {
+func (s *ChainService) HeadValidatorsIndices(ctx context.Context, epoch primitives.Epoch) ([]primitives.ValidatorIndex, error) {
 	if s.State == nil {
-		return []types.ValidatorIndex{}, nil
+		return []primitives.ValidatorIndex{}, nil
 	}
 	return helpers.ActiveValidatorIndices(ctx, s.State, epoch)
 }
@@ -338,11 +346,11 @@ func (s *ChainService) GenesisValidatorsRoot() [32]byte {
 }

 // CurrentSlot mocks the same method in the chain service.
-func (s *ChainService) CurrentSlot() types.Slot {
+func (s *ChainService) CurrentSlot() primitives.Slot {
 	if s.Slot != nil {
 		return *s.Slot
 	}
-	return types.Slot(uint64(time.Now().Unix()-s.Genesis.Unix()) / params.BeaconConfig().SecondsPerSlot)
+	return primitives.Slot(uint64(time.Now().Unix()-s.Genesis.Unix()) / params.BeaconConfig().SecondsPerSlot)
 }

 // Participation mocks the same method in the chain service.
@@ -384,11 +392,6 @@ func (_ *ChainService) HeadGenesisValidatorsRoot() [32]byte {
 	return [32]byte{}
 }

-// VerifyFinalizedBlkDescendant mocks VerifyBlkDescendant and always returns nil.
-func (s *ChainService) VerifyFinalizedBlkDescendant(_ context.Context, _ [32]byte) error {
-	return s.VerifyBlkDescendantErr
-}
-
 // VerifyLmdFfgConsistency mocks VerifyLmdFfgConsistency and always returns nil.
 func (_ *ChainService) VerifyLmdFfgConsistency(_ context.Context, a *ethpb.Attestation) error {
 	if !bytes.Equal(a.Data.BeaconBlockRoot, a.Data.Target.Root) {
@@ -397,55 +400,47 @@ func (_ *ChainService) VerifyLmdFfgConsistency(_ context.Context, a *ethpb.Attes
 	return nil
 }

-// VerifyFinalizedConsistency mocks VerifyFinalizedConsistency and always returns nil.
-func (s *ChainService) VerifyFinalizedConsistency(_ context.Context, r []byte) error {
-	if !bytes.Equal(r, s.FinalizedCheckPoint.Root) {
-		return errors.New("Root and finalized store are not consistent")
-	}
-	return nil
-}
-
 // ChainHeads mocks ChainHeads and always return nil.
-func (_ *ChainService) ChainHeads() ([][32]byte, []types.Slot) {
+func (_ *ChainService) ChainHeads() ([][32]byte, []primitives.Slot) {
 	return [][32]byte{
 			bytesutil.ToBytes32(bytesutil.PadTo([]byte("foo"), 32)),
 			bytesutil.ToBytes32(bytesutil.PadTo([]byte("bar"), 32)),
 		},
-		[]types.Slot{0, 1}
+		[]primitives.Slot{0, 1}
 }

 // HeadPublicKeyToValidatorIndex mocks HeadPublicKeyToValidatorIndex and always return 0 and true.
-func (_ *ChainService) HeadPublicKeyToValidatorIndex(_ [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool) {
+func (_ *ChainService) HeadPublicKeyToValidatorIndex(_ [fieldparams.BLSPubkeyLength]byte) (primitives.ValidatorIndex, bool) {
 	return 0, true
 }

 // HeadValidatorIndexToPublicKey mocks HeadValidatorIndexToPublicKey and always return empty and nil.
-func (s *ChainService) HeadValidatorIndexToPublicKey(_ context.Context, _ types.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error) {
+func (s *ChainService) HeadValidatorIndexToPublicKey(_ context.Context, _ primitives.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error) {
 	return s.PublicKey, nil
 }

 // HeadSyncCommitteeIndices mocks HeadSyncCommitteeIndices and always return `HeadNextSyncCommitteeIndices`.
-func (s *ChainService) HeadSyncCommitteeIndices(_ context.Context, _ types.ValidatorIndex, _ types.Slot) ([]types.CommitteeIndex, error) {
+func (s *ChainService) HeadSyncCommitteeIndices(_ context.Context, _ primitives.ValidatorIndex, _ primitives.Slot) ([]primitives.CommitteeIndex, error) {
 	return s.SyncCommitteeIndices, nil
 }

 // HeadSyncCommitteePubKeys mocks HeadSyncCommitteePubKeys and always return empty nil.
-func (s *ChainService) HeadSyncCommitteePubKeys(_ context.Context, _ types.Slot, _ types.CommitteeIndex) ([][]byte, error) {
+func (s *ChainService) HeadSyncCommitteePubKeys(_ context.Context, _ primitives.Slot, _ primitives.CommitteeIndex) ([][]byte, error) {
 	return s.SyncCommitteePubkeys, nil
 }

 // HeadSyncCommitteeDomain mocks HeadSyncCommitteeDomain and always return empty nil.
-func (s *ChainService) HeadSyncCommitteeDomain(_ context.Context, _ types.Slot) ([]byte, error) {
+func (s *ChainService) HeadSyncCommitteeDomain(_ context.Context, _ primitives.Slot) ([]byte, error) {
 	return s.SyncCommitteeDomain, nil
 }

 // HeadSyncSelectionProofDomain mocks HeadSyncSelectionProofDomain and always return empty nil.
-func (s *ChainService) HeadSyncSelectionProofDomain(_ context.Context, _ types.Slot) ([]byte, error) {
+func (s *ChainService) HeadSyncSelectionProofDomain(_ context.Context, _ primitives.Slot) ([]byte, error) {
 	return s.SyncSelectionProofDomain, nil
 }

 // HeadSyncContributionProofDomain mocks HeadSyncContributionProofDomain and always return empty nil.
-func (s *ChainService) HeadSyncContributionProofDomain(_ context.Context, _ types.Slot) ([]byte, error) {
+func (s *ChainService) HeadSyncContributionProofDomain(_ context.Context, _ primitives.Slot) ([]byte, error) {
 	return s.SyncContributionProofDomain, nil
 }

@@ -454,6 +449,11 @@ func (s *ChainService) IsOptimistic(_ context.Context) (bool, error) {
 	return s.Optimistic, nil
 }

+// InForkchoice mocks the same method in the chain service
+func (s *ChainService) InForkchoice(_ [32]byte) bool {
+	return !s.NotFinalized
+}
+
 // IsOptimisticForRoot mocks the same method in the chain service.
 func (s *ChainService) IsOptimisticForRoot(_ context.Context, root [32]byte) (bool, error) {
 	s.OptimisticCheckRootReceived = root
@@ -461,7 +461,17 @@ func (s *ChainService) IsOptimisticForRoot(_ context.Context, root [32]byte) (bo
 }

 // UpdateHead mocks the same method in the chain service.
-func (s *ChainService) UpdateHead(_ context.Context) error { return nil }
+func (s *ChainService) UpdateHead(ctx context.Context, slot primitives.Slot) {
+	ojc := &ethpb.Checkpoint{}
+	st, root, err := prepareForkchoiceState(ctx, slot, bytesutil.ToBytes32(s.Root), [32]byte{}, [32]byte{}, ojc, ojc)
+	if err != nil {
+		logrus.WithError(err).Error("could not update head")
+	}
+	err = s.ForkChoicer().InsertNode(ctx, st, root)
+	if err != nil {
+		logrus.WithError(err).Error("could not insert node to forkchoice")
+	}
+}

 // ReceiveAttesterSlashing mocks the same method in the chain service.
 func (s *ChainService) ReceiveAttesterSlashing(context.Context, *ethpb.AttesterSlashing) {}
@@ -470,3 +480,37 @@ func (s *ChainService) ReceiveAttesterSlashing(context.Context, *ethpb.AttesterS
 func (s *ChainService) IsFinalized(_ context.Context, blockRoot [32]byte) bool {
 	return s.FinalizedRoots[blockRoot]
 }
+
+// prepareForkchoiceState prepares a beacon state with the given data to mock
+// insert into forkchoice
+func prepareForkchoiceState(
+	_ context.Context,
+	slot primitives.Slot,
+	blockRoot [32]byte,
+	parentRoot [32]byte,
+	payloadHash [32]byte,
+	justified *ethpb.Checkpoint,
+	finalized *ethpb.Checkpoint,
+) (state.BeaconState, [32]byte, error) {
+	blockHeader := &ethpb.BeaconBlockHeader{
+		ParentRoot: parentRoot[:],
+	}
+
+	executionHeader := &enginev1.ExecutionPayloadHeader{
+		BlockHash: payloadHash[:],
+	}
+
+	base := &ethpb.BeaconStateBellatrix{
+		Slot:                         slot,
+		RandaoMixes:                  make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+		BlockRoots:                   make([][]byte, 1),
+		CurrentJustifiedCheckpoint:   justified,
+		FinalizedCheckpoint:          finalized,
+		LatestExecutionPayloadHeader: executionHeader,
+		LatestBlockHeader:            blockHeader,
+	}
+
+	base.BlockRoots[0] = append(base.BlockRoots[0], blockRoot[:]...)
+	st, err := state_native.InitializeFromProtoBellatrix(base)
+	return st, blockRoot, err
+}
--- a/beacon-chain/blockchain/weak_subjectivity_checks.go
+++ b/beacon-chain/blockchain/weak_subjectivity_checks.go
@@ -7,7 +7,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/db/filters"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
@@ -22,8 +22,8 @@ type WeakSubjectivityVerifier struct {
 	enabled  bool
 	verified bool
 	root     [32]byte
-	epoch    types.Epoch
-	slot     types.Slot
+	epoch    primitives.Epoch
+	slot     primitives.Slot
 	db       weakSubjectivityDB
 }

@@ -51,7 +51,7 @@ func NewWeakSubjectivityVerifier(wsc *ethpb.Checkpoint, db weakSubjectivityDB) (

 // VerifyWeakSubjectivity verifies the weak subjectivity root in the service struct.
 // Reference design: https://github.com/ethereum/consensus-specs/blob/master/specs/phase0/weak-subjectivity.md#weak-subjectivity-sync-procedure
-func (v *WeakSubjectivityVerifier) VerifyWeakSubjectivity(ctx context.Context, finalizedEpoch types.Epoch) error {
+func (v *WeakSubjectivityVerifier) VerifyWeakSubjectivity(ctx context.Context, finalizedEpoch primitives.Epoch) error {
 	if v.verified || !v.enabled {
 		return nil
 	}
--- a/beacon-chain/blockchain/weak_subjectivity_checks_test.go
+++ b/beacon-chain/blockchain/weak_subjectivity_checks_test.go
@@ -9,7 +9,7 @@ import (
 	doublylinkedtree "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/prysmaticlabs/prysm/v3/beacon-chain/forkchoice/types"
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
@@ -32,7 +32,7 @@ func TestService_VerifyWeakSubjectivityRoot(t *testing.T) {
 		disabled       bool
 		wantErr        error
 		checkpt        *ethpb.Checkpoint
-		finalizedEpoch types.Epoch
+		finalizedEpoch primitives.Epoch
 		name           string
 	}{
 		{
--- a/beacon-chain/builder/BUILD.bazel
+++ b/beacon-chain/builder/BUILD.bazel
@@ -14,9 +14,9 @@ go_library(
        "//beacon-chain/blockchain:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//cmd/beacon-chain/flags:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//encoding/bytesutil:go_default_library",
-        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
--- a/beacon-chain/builder/service.go
+++ b/beacon-chain/builder/service.go
@@ -9,9 +9,9 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/api/client/builder"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/blockchain"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/db"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	log "github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
@@ -22,8 +22,8 @@ var ErrNoBuilder = errors.New("builder endpoint not configured")

 // BlockBuilder defines the interface for interacting with the block builder
 type BlockBuilder interface {
-	SubmitBlindedBlock(ctx context.Context, block *ethpb.SignedBlindedBeaconBlockBellatrix) (*v1.ExecutionPayload, error)
-	GetHeader(ctx context.Context, slot types.Slot, parentHash [32]byte, pubKey [48]byte) (*ethpb.SignedBuilderBid, error)
+	SubmitBlindedBlock(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, error)
+	GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubKey [48]byte) (builder.SignedBid, error)
 	RegisterValidator(ctx context.Context, reg []*ethpb.SignedValidatorRegistrationV1) error
 	Configured() bool
 }
@@ -82,7 +82,7 @@ func (*Service) Stop() error {
 }

 // SubmitBlindedBlock submits a blinded block to the builder relay network.
-func (s *Service) SubmitBlindedBlock(ctx context.Context, b *ethpb.SignedBlindedBeaconBlockBellatrix) (*v1.ExecutionPayload, error) {
+func (s *Service) SubmitBlindedBlock(ctx context.Context, b interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, error) {
 	ctx, span := trace.StartSpan(ctx, "builder.SubmitBlindedBlock")
 	defer span.End()
 	start := time.Now()
@@ -94,7 +94,7 @@ func (s *Service) SubmitBlindedBlock(ctx context.Context, b *ethpb.SignedBlinded
 }

 // GetHeader retrieves the header for a given slot and parent hash from the builder relay network.
-func (s *Service) GetHeader(ctx context.Context, slot types.Slot, parentHash [32]byte, pubKey [48]byte) (*ethpb.SignedBuilderBid, error) {
+func (s *Service) GetHeader(ctx context.Context, slot primitives.Slot, parentHash [32]byte, pubKey [48]byte) (builder.SignedBid, error) {
 	ctx, span := trace.StartSpan(ctx, "builder.GetHeader")
 	defer span.End()
 	start := time.Now()
@@ -125,7 +125,7 @@ func (s *Service) RegisterValidator(ctx context.Context, reg []*ethpb.SignedVali
 		registerValidatorLatency.Observe(float64(time.Since(start).Milliseconds()))
 	}()

-	idxs := make([]types.ValidatorIndex, 0)
+	idxs := make([]primitives.ValidatorIndex, 0)
 	msgs := make([]*ethpb.ValidatorRegistrationV1, 0)
 	valid := make([]*ethpb.SignedValidatorRegistrationV1, 0)
 	for i := 0; i < len(reg); i++ {
--- a/beacon-chain/builder/testing/BUILD.bazel
+++ b/beacon-chain/builder/testing/BUILD.bazel
@@ -7,8 +7,14 @@ go_library(
    importpath = "github.com/prysmaticlabs/prysm/v3/beacon-chain/builder/testing",
    visibility = ["//visibility:public"],
    deps = [
+        "//api/client/builder:go_default_library",
+        "//config/params:go_default_library",
+        "//consensus-types/blocks:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
+        "//time/slots:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
    ],
 )
--- a/beacon-chain/builder/testing/mock.go
+++ b/beacon-chain/builder/testing/mock.go
@@ -2,18 +2,27 @@ package testing

 import (
 	"context"
+	"math/big"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/api/client/builder"
+	"github.com/prysmaticlabs/prysm/v3/config/params"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	v1 "github.com/prysmaticlabs/prysm/v3/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/time/slots"
 )

 // MockBuilderService to mock builder.
 type MockBuilderService struct {
 	HasConfigured         bool
 	Payload               *v1.ExecutionPayload
+	PayloadCapella        *v1.ExecutionPayloadCapella
 	ErrSubmitBlindedBlock error
 	Bid                   *ethpb.SignedBuilderBid
+	BidCapella            *ethpb.SignedBuilderBidCapella
 	ErrGetHeader          error
 	ErrRegisterValidator  error
 }
@@ -24,13 +33,31 @@ func (s *MockBuilderService) Configured() bool {
 }

 // SubmitBlindedBlock for mocking.
-func (s *MockBuilderService) SubmitBlindedBlock(context.Context, *ethpb.SignedBlindedBeaconBlockBellatrix) (*v1.ExecutionPayload, error) {
-	return s.Payload, s.ErrSubmitBlindedBlock
+func (s *MockBuilderService) SubmitBlindedBlock(_ context.Context, _ interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, error) {
+	if s.Payload != nil {
+		w, err := blocks.WrappedExecutionPayload(s.Payload)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not wrap payload")
+		}
+		return w, s.ErrSubmitBlindedBlock
+	}
+	w, err := blocks.WrappedExecutionPayloadCapella(s.PayloadCapella, big.NewInt(0))
+	if err != nil {
+		return nil, errors.Wrap(err, "could not wrap capella payload")
+	}
+	return w, s.ErrSubmitBlindedBlock
 }

 // GetHeader for mocking.
-func (s *MockBuilderService) GetHeader(context.Context, types.Slot, [32]byte, [48]byte) (*ethpb.SignedBuilderBid, error) {
-	return s.Bid, s.ErrGetHeader
+func (s *MockBuilderService) GetHeader(ctx context.Context, slot primitives.Slot, hr [32]byte, pb [48]byte) (builder.SignedBid, error) {
+	if slots.ToEpoch(slot) >= params.BeaconConfig().CapellaForkEpoch {
+		return builder.WrappedSignedBuilderBidCapella(s.BidCapella)
+	}
+	w, err := builder.WrappedSignedBuilderBid(s.Bid)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not wrap capella bid")
+	}
+	return w, s.ErrGetHeader
 }

 // RegisterValidator for mocking.
--- a/beacon-chain/cache/active_balance.go
+++ b/beacon-chain/cache/active_balance.go
@@ -13,7 +13,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	lruwrpr "github.com/prysmaticlabs/prysm/v3/cache/lru"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	ethTypes "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 )

 const (
@@ -90,7 +90,7 @@ func balanceCacheKey(st state.ReadOnlyBeaconState) (string, error) {
 		// impossible condition due to early division
 		return "", errors.Errorf("start slot calculation overflows: %v", err)
 	}
-	prevSlot := ethTypes.Slot(0)
+	prevSlot := primitives.Slot(0)
 	if epochStartSlot > 1 {
 		prevSlot = epochStartSlot - 1
 	}
--- a/beacon-chain/cache/active_balance_test.go
+++ b/beacon-chain/cache/active_balance_test.go
@@ -9,7 +9,7 @@ import (

 	state_native "github.com/prysmaticlabs/prysm/v3/beacon-chain/state/state-native"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 )
@@ -70,7 +70,7 @@ func TestBalanceCache_BalanceKey(t *testing.T) {
 	}
 	st, err := state_native.InitializeFromProtoPhase0(raw)
 	require.NoError(t, err)
-	require.NoError(t, st.SetSlot(types.Slot(math.MaxUint64)))
+	require.NoError(t, st.SetSlot(primitives.Slot(math.MaxUint64)))

 	_, err = balanceCacheKey(st)
 	require.NoError(t, err)
--- a/beacon-chain/cache/checkpoint_state.go
+++ b/beacon-chain/cache/checkpoint_state.go
@@ -1,8 +1,6 @@
 package cache

 import (
-	"sync"
-
 	lru "github.com/hashicorp/golang-lru"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
@@ -32,7 +30,6 @@ var (
 // CheckpointStateCache is a struct with 1 queue for looking up state by checkpoint.
 type CheckpointStateCache struct {
 	cache *lru.Cache
-	lock  sync.RWMutex
 }

 // NewCheckpointStateCache creates a new checkpoint state cache for storing/accessing processed state.
@@ -45,8 +42,6 @@ func NewCheckpointStateCache() *CheckpointStateCache {
 // StateByCheckpoint fetches state by checkpoint. Returns true with a
 // reference to the CheckpointState info, if exists. Otherwise returns false, nil.
 func (c *CheckpointStateCache) StateByCheckpoint(cp *ethpb.Checkpoint) (state.BeaconState, error) {
-	c.lock.RLock()
-	defer c.lock.RUnlock()
 	h, err := hash.HashProto(cp)
 	if err != nil {
 		return nil, err
@@ -67,8 +62,6 @@ func (c *CheckpointStateCache) StateByCheckpoint(cp *ethpb.Checkpoint) (state.Be
 // AddCheckpointState adds CheckpointState object to the cache. This method also trims the least
 // recently added CheckpointState object if the cache size has ready the max cache size limit.
 func (c *CheckpointStateCache) AddCheckpointState(cp *ethpb.Checkpoint, s state.ReadOnlyBeaconState) error {
-	c.lock.Lock()
-	defer c.lock.Unlock()
 	h, err := hash.HashProto(cp)
 	if err != nil {
 		return err
--- a/beacon-chain/cache/checkpoint_state_test.go
+++ b/beacon-chain/cache/checkpoint_state_test.go
@@ -6,7 +6,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	state_native "github.com/prysmaticlabs/prysm/v3/beacon-chain/state/state-native"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/assert"
@@ -65,8 +65,8 @@ func TestCheckpointStateCache_MaxSize(t *testing.T) {
 	require.NoError(t, err)

 	for i := uint64(0); i < uint64(maxCheckpointStateSize+100); i++ {
-		require.NoError(t, st.SetSlot(types.Slot(i)))
-		require.NoError(t, c.AddCheckpointState(&ethpb.Checkpoint{Epoch: types.Epoch(i), Root: make([]byte, 32)}, st))
+		require.NoError(t, st.SetSlot(primitives.Slot(i)))
+		require.NoError(t, c.AddCheckpointState(&ethpb.Checkpoint{Epoch: primitives.Epoch(i), Root: make([]byte, 32)}, st))
 	}

 	assert.Equal(t, maxCheckpointStateSize, len(c.cache.Keys()))
--- a/beacon-chain/cache/committee.go
+++ b/beacon-chain/cache/committee.go
@@ -14,7 +14,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	lruwrpr "github.com/prysmaticlabs/prysm/v3/cache/lru"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/container/slice"
 	mathutil "github.com/prysmaticlabs/prysm/v3/math"
 )
@@ -64,7 +64,7 @@ func NewCommitteesCache() *CommitteeCache {

 // Committee fetches the shuffled indices by slot and committee index. Every list of indices
 // represent one committee. Returns true if the list exists with slot and committee index. Otherwise returns false, nil.
-func (c *CommitteeCache) Committee(ctx context.Context, slot types.Slot, seed [32]byte, index types.CommitteeIndex) ([]types.ValidatorIndex, error) {
+func (c *CommitteeCache) Committee(ctx context.Context, slot primitives.Slot, seed [32]byte, index primitives.CommitteeIndex) ([]primitives.ValidatorIndex, error) {
 	if err := c.checkInProgress(ctx, seed); err != nil {
 		return nil, err
 	}
@@ -117,7 +117,7 @@ func (c *CommitteeCache) AddCommitteeShuffledList(ctx context.Context, committee
 }

 // ActiveIndices returns the active indices of a given seed stored in cache.
-func (c *CommitteeCache) ActiveIndices(ctx context.Context, seed [32]byte) ([]types.ValidatorIndex, error) {
+func (c *CommitteeCache) ActiveIndices(ctx context.Context, seed [32]byte) ([]primitives.ValidatorIndex, error) {
 	if err := c.checkInProgress(ctx, seed); err != nil {
 		return nil, err
 	}
--- a/beacon-chain/cache/committee_disabled.go
+++ b/beacon-chain/cache/committee_disabled.go
@@ -6,7 +6,7 @@ package cache
 import (
 	"context"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 )

 // FakeCommitteeCache is a struct with 1 queue for looking up shuffled indices list by seed.
@@ -20,7 +20,7 @@ func NewCommitteesCache() *FakeCommitteeCache {

 // Committee fetches the shuffled indices by slot and committee index. Every list of indices
 // represent one committee. Returns true if the list exists with slot and committee index. Otherwise returns false, nil.
-func (c *FakeCommitteeCache) Committee(ctx context.Context, slot types.Slot, seed [32]byte, index types.CommitteeIndex) ([]types.ValidatorIndex, error) {
+func (c *FakeCommitteeCache) Committee(ctx context.Context, slot primitives.Slot, seed [32]byte, index primitives.CommitteeIndex) ([]primitives.ValidatorIndex, error) {
 	return nil, nil
 }

@@ -31,12 +31,12 @@ func (c *FakeCommitteeCache) AddCommitteeShuffledList(ctx context.Context, commi
 }

 // AddProposerIndicesList updates the committee shuffled list with proposer indices.
-func (c *FakeCommitteeCache) AddProposerIndicesList(seed [32]byte, indices []types.ValidatorIndex) error {
+func (c *FakeCommitteeCache) AddProposerIndicesList(seed [32]byte, indices []primitives.ValidatorIndex) error {
 	return nil
 }

 // ActiveIndices returns the active indices of a given seed stored in cache.
-func (c *FakeCommitteeCache) ActiveIndices(ctx context.Context, seed [32]byte) ([]types.ValidatorIndex, error) {
+func (c *FakeCommitteeCache) ActiveIndices(ctx context.Context, seed [32]byte) ([]primitives.ValidatorIndex, error) {
 	return nil, nil
 }

@@ -51,7 +51,7 @@ func (c *FakeCommitteeCache) ActiveBalance(seed [32]byte) (uint64, error) {
 }

 // ProposerIndices returns the proposer indices of a given seed.
-func (c *FakeCommitteeCache) ProposerIndices(seed [32]byte) ([]types.ValidatorIndex, error) {
+func (c *FakeCommitteeCache) ProposerIndices(seed [32]byte) ([]primitives.ValidatorIndex, error) {
 	return nil, nil
 }

--- a/beacon-chain/cache/committee_test.go
+++ b/beacon-chain/cache/committee_test.go
@@ -10,7 +10,7 @@ import (
 	"testing"

 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v3/testing/assert"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
@@ -20,7 +20,7 @@ func TestCommitteeKeyFn_OK(t *testing.T) {
 	item := &Committees{
 		CommitteeCount:  1,
 		Seed:            [32]byte{'A'},
-		ShuffledIndices: []types.ValidatorIndex{1, 2, 3, 4, 5},
+		ShuffledIndices: []primitives.ValidatorIndex{1, 2, 3, 4, 5},
 	}

 	k, err := committeeKeyFn(item)
@@ -37,13 +37,13 @@ func TestCommitteeCache_CommitteesByEpoch(t *testing.T) {
 	cache := NewCommitteesCache()

 	item := &Committees{
-		ShuffledIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6},
+		ShuffledIndices: []primitives.ValidatorIndex{1, 2, 3, 4, 5, 6},
 		Seed:            [32]byte{'A'},
 		CommitteeCount:  3,
 	}

 	slot := params.BeaconConfig().SlotsPerEpoch
-	committeeIndex := types.CommitteeIndex(1)
+	committeeIndex := primitives.CommitteeIndex(1)
 	indices, err := cache.Committee(context.Background(), slot, item.Seed, committeeIndex)
 	require.NoError(t, err)
 	if indices != nil {
@@ -51,7 +51,7 @@ func TestCommitteeCache_CommitteesByEpoch(t *testing.T) {
 	}
 	require.NoError(t, cache.AddCommitteeShuffledList(context.Background(), item))

-	wantedIndex := types.CommitteeIndex(0)
+	wantedIndex := primitives.CommitteeIndex(0)
 	indices, err = cache.Committee(context.Background(), slot, item.Seed, wantedIndex)
 	require.NoError(t, err)

@@ -62,7 +62,7 @@ func TestCommitteeCache_CommitteesByEpoch(t *testing.T) {
 func TestCommitteeCache_ActiveIndices(t *testing.T) {
 	cache := NewCommitteesCache()

-	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6}}
+	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []primitives.ValidatorIndex{1, 2, 3, 4, 5, 6}}
 	indices, err := cache.ActiveIndices(context.Background(), item.Seed)
 	require.NoError(t, err)
 	if indices != nil {
@@ -79,7 +79,7 @@ func TestCommitteeCache_ActiveIndices(t *testing.T) {
 func TestCommitteeCache_ActiveCount(t *testing.T) {
 	cache := NewCommitteesCache()

-	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6}}
+	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []primitives.ValidatorIndex{1, 2, 3, 4, 5, 6}}
 	count, err := cache.ActiveIndicesCount(context.Background(), item.Seed)
 	require.NoError(t, err)
 	assert.Equal(t, 0, count, "Expected active count not to exist in empty cache")
@@ -123,8 +123,8 @@ func TestCommitteeCacheOutOfRange(t *testing.T) {
 	comms := &Committees{
 		CommitteeCount:  1,
 		Seed:            seed,
-		ShuffledIndices: []types.ValidatorIndex{0},
-		SortedIndices:   []types.ValidatorIndex{},
+		ShuffledIndices: []primitives.ValidatorIndex{0},
+		SortedIndices:   []primitives.ValidatorIndex{},
 	}
 	key, err := committeeKeyFn(comms)
 	assert.NoError(t, err)
@@ -137,7 +137,7 @@ func TestCommitteeCacheOutOfRange(t *testing.T) {
 func TestCommitteeCache_DoesNothingWhenCancelledContext(t *testing.T) {
 	cache := NewCommitteesCache()

-	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6}}
+	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []primitives.ValidatorIndex{1, 2, 3, 4, 5, 6}}
 	count, err := cache.ActiveIndicesCount(context.Background(), item.Seed)
 	require.NoError(t, err)
 	assert.Equal(t, 0, count, "Expected active count not to exist in empty cache")
--- a/beacon-chain/cache/committees.go
+++ b/beacon-chain/cache/committees.go
@@ -3,7 +3,7 @@ package cache
 import (
 	"errors"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 )

 // ErrNotCommittee will be returned when a cache object is not a pointer to
@@ -14,6 +14,6 @@ var ErrNotCommittee = errors.New("object is not a committee struct")
 type Committees struct {
 	CommitteeCount  uint64
 	Seed            [32]byte
-	ShuffledIndices []types.ValidatorIndex
-	SortedIndices   []types.ValidatorIndex
+	ShuffledIndices []primitives.ValidatorIndex
+	SortedIndices   []primitives.ValidatorIndex
 }
--- a/beacon-chain/cache/depositsnapshot/BUILD.bazel
+++ b/beacon-chain/cache/depositsnapshot/BUILD.bazel
@@ -2,7 +2,20 @@ load("@prysm//tools/go:def.bzl", "go_library")

 go_library(
    name = "go_default_library",
-    srcs = ["merkle_tree.go"],
+    srcs = [
+        "deposit_tree.go",
+        "deposit_tree_snapshot.go",
+        "merkle_tree.go",
+        "zerohashes.gen.go",
+    ],
    importpath = "github.com/prysmaticlabs/prysm/v3/beacon-chain/cache/depositsnapshot",
    visibility = ["//visibility:public"],
+    deps = [
+        "//container/slice:go_default_library",
+        "//crypto/hash:go_default_library",
+        "//encoding/bytesutil:go_default_library",
+        "//math:go_default_library",
+        "//proto/eth/v1:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+    ],
 )
--- a/beacon-chain/cache/depositsnapshot/deposit_tree.go
+++ b/beacon-chain/cache/depositsnapshot/deposit_tree.go
@@ -0,0 +1,157 @@
+// Package depositsnapshot implements the EIP-4881 standard for minimal sparse Merkle tree.
+// The format proposed by the EIP allows for the pruning of deposits that are no longer needed to participate fully in consensus.
+// Full EIP-4881 specification can be found here: https://eips.ethereum.org/EIPS/eip-4881
+package depositsnapshot
+
+import (
+	"crypto/sha256"
+
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v3/math"
+	eth "github.com/prysmaticlabs/prysm/v3/proto/eth/v1"
+)
+
+var (
+	// ErrEmptyExecutionBlock occurs when the execution block is nil.
+	ErrEmptyExecutionBlock = errors.New("empty execution block")
+	// ErrInvalidSnapshotRoot occurs when the snapshot root does not match the calculated root.
+	ErrInvalidSnapshotRoot = errors.New("snapshot root is invalid")
+	// ErrInvalidMixInLength occurs when the value for mix in length is 0.
+	ErrInvalidMixInLength = errors.New("mixInLength should be greater than 0")
+	// ErrInvalidIndex occurs when the index is less than the number of finalized deposits.
+	ErrInvalidIndex = errors.New("index should be greater than finalizedDeposits - 1")
+	// ErrNoDeposits occurs when the number of deposits is 0.
+	ErrNoDeposits = errors.New("number of deposits should be greater than 0")
+	// ErrNoFinalizedDeposits occurs when the number of finalized deposits is 0.
+	ErrNoFinalizedDeposits = errors.New("number of finalized deposits should be greater than 0")
+	// ErrTooManyDeposits occurs when the number of deposits exceeds the capacity of the tree.
+	ErrTooManyDeposits = errors.New("number of deposits should not be greater than the capacity of the tree")
+)
+
+// DepositTree is the Merkle tree representation of deposits.
+type DepositTree struct {
+	tree                    MerkleTreeNode
+	mixInLength             uint64 // number of deposits in the tree, reference implementation calls this mix_in_length.
+	finalizedExecutionBlock executionBlock
+}
+
+type executionBlock struct {
+	Hash  [32]byte
+	Depth uint64
+}
+
+// New creates an empty deposit tree.
+//
+//nolint:unused
+func New() *DepositTree {
+	var leaves [][32]byte
+	merkle := create(leaves, DepositContractDepth)
+	return &DepositTree{
+		tree:                    merkle,
+		mixInLength:             0,
+		finalizedExecutionBlock: executionBlock{},
+	}
+}
+
+// getSnapshot returns a deposit tree snapshot.
+//
+//nolint:unused
+func (d *DepositTree) getSnapshot() (DepositTreeSnapshot, error) {
+	if d.finalizedExecutionBlock == (executionBlock{}) {
+		return DepositTreeSnapshot{}, ErrEmptyExecutionBlock
+	}
+	var finalized [][32]byte
+	depositCount, _ := d.tree.GetFinalized(finalized)
+	return fromTreeParts(finalized, depositCount, d.finalizedExecutionBlock)
+}
+
+// fromSnapshot returns a deposit tree from a deposit tree snapshot.
+//
+//nolint:unused
+func fromSnapshot(snapshot DepositTreeSnapshot) (DepositTree, error) {
+	root, err := snapshot.CalculateRoot()
+	if err != nil {
+		return DepositTree{}, err
+	}
+	if snapshot.depositRoot != root {
+		return DepositTree{}, ErrInvalidSnapshotRoot
+	}
+	if snapshot.depositCount >= math.PowerOf2(uint64(DepositContractDepth)) {
+		return DepositTree{}, ErrTooManyDeposits
+	}
+	tree, err := fromSnapshotParts(snapshot.finalized, snapshot.depositCount, DepositContractDepth)
+	if err != nil {
+		return DepositTree{}, err
+	}
+	if snapshot.depositCount == 0 {
+		return DepositTree{}, ErrNoDeposits
+	}
+	return DepositTree{
+		tree:                    tree,
+		mixInLength:             snapshot.depositCount,
+		finalizedExecutionBlock: snapshot.executionBlock,
+	}, nil
+}
+
+// finalize marks a deposit as finalized.
+//
+//nolint:unused
+func (d *DepositTree) finalize(eth1data *eth.Eth1Data, executionBlockHeight uint64) error {
+	var blockHash [32]byte
+	copy(blockHash[:], eth1data.BlockHash)
+	d.finalizedExecutionBlock = executionBlock{
+		Hash:  blockHash,
+		Depth: executionBlockHeight,
+	}
+	_, err := d.tree.Finalize(eth1data.DepositCount, DepositContractDepth)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// getProof returns the Deposit tree proof.
+//
+//nolint:unused
+func (d *DepositTree) getProof(index uint64) ([32]byte, [][32]byte, error) {
+	if d.mixInLength <= 0 {
+		return [32]byte{}, nil, ErrInvalidMixInLength
+	}
+	finalizedDeposits, _ := d.tree.GetFinalized([][32]byte{})
+	if finalizedDeposits == 0 {
+		return [32]byte{}, nil, ErrNoFinalizedDeposits
+	}
+	if finalizedDeposits != 0 {
+		finalizedDeposits = finalizedDeposits - 1
+	}
+	if index <= finalizedDeposits {
+		return [32]byte{}, nil, ErrInvalidIndex
+	}
+	leaf, proof := generateProof(d.tree, index, DepositContractDepth)
+	var mixInLength [32]byte
+	copy(mixInLength[:], bytesutil.Uint64ToBytesLittleEndian32(d.mixInLength))
+	proof = append(proof, mixInLength)
+	return leaf, proof, nil
+}
+
+// getRoot returns the root of the deposit tree.
+//
+//nolint:unused
+func (d *DepositTree) getRoot() [32]byte {
+	root := d.tree.GetRoot()
+	return sha256.Sum256(append(root[:], bytesutil.Uint64ToBytesLittleEndian32(d.mixInLength)...))
+}
+
+// pushLeaf adds a new leaf to the tree.
+//
+//nolint:unused
+func (d *DepositTree) pushLeaf(leaf [32]byte) error {
+	var err error
+	d.tree, err = d.tree.PushLeaf(leaf, DepositContractDepth)
+	if err != nil {
+		return err
+	}
+	d.mixInLength++
+	return nil
+}
--- a/beacon-chain/cache/depositsnapshot/deposit_tree_snapshot.go
+++ b/beacon-chain/cache/depositsnapshot/deposit_tree_snapshot.go
@@ -0,0 +1,62 @@
+package depositsnapshot
+
+import (
+	"crypto/sha256"
+
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
+)
+
+var (
+	// ErrZeroIndex occurs when the value of index is 0.
+	ErrZeroIndex = errors.New("index should be greater than 0")
+)
+
+// DepositTreeSnapshot represents the data used to create a
+// deposit tree given a snapshot.
+//
+//nolint:unused
+type DepositTreeSnapshot struct {
+	finalized      [][32]byte
+	depositRoot    [32]byte
+	depositCount   uint64
+	executionBlock executionBlock
+}
+
+// CalculateRoot returns the root of a deposit tree snapshot.
+func (ds *DepositTreeSnapshot) CalculateRoot() ([32]byte, error) {
+	size := ds.depositCount
+	index := len(ds.finalized)
+	root := Zerohashes[0]
+	for i := 0; i < DepositContractDepth; i++ {
+		if (size & 1) == 1 {
+			if index == 0 {
+				return [32]byte{}, ErrZeroIndex
+			}
+			index--
+			root = sha256.Sum256(append(ds.finalized[index][:], root[:]...))
+		} else {
+			root = sha256.Sum256(append(root[:], Zerohashes[i][:]...))
+		}
+		size >>= 1
+	}
+	return sha256.Sum256(append(root[:], bytesutil.Uint64ToBytesLittleEndian(ds.depositCount)...)), nil
+}
+
+// fromTreeParts constructs the deposit tree from pre-existing data.
+//
+//nolint:unused
+func fromTreeParts(finalised [][32]byte, depositCount uint64, executionBlock executionBlock) (DepositTreeSnapshot, error) {
+	snapshot := DepositTreeSnapshot{
+		finalized:      finalised,
+		depositRoot:    Zerohashes[0],
+		depositCount:   depositCount,
+		executionBlock: executionBlock,
+	}
+	root, err := snapshot.CalculateRoot()
+	if err != nil {
+		return snapshot, ErrInvalidSnapshotRoot
+	}
+	snapshot.depositRoot = root
+	return snapshot, nil
+}
--- a/beacon-chain/cache/depositsnapshot/merkle_tree.go
+++ b/beacon-chain/cache/depositsnapshot/merkle_tree.go
@@ -1,7 +1,26 @@
 package depositsnapshot

+import (
+	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/prysm/v3/container/slice"
+	"github.com/prysmaticlabs/prysm/v3/crypto/hash"
+	"github.com/prysmaticlabs/prysm/v3/math"
+)
+
 const (
-	DepositContractDepth = 32 // Maximum tree depth as defined by EIP-4881.
+	// DepositContractDepth is the maximum tree depth as defined by EIP-4881.
+	DepositContractDepth = 32
+)
+
+var (
+	// ErrFinalizedNodeCannotPushLeaf may occur when attempting to push a leaf to a finalized node. When a node is finalized, it cannot be modified or changed.
+	ErrFinalizedNodeCannotPushLeaf = errors.New("can't push a leaf to a finalized node")
+	// ErrLeafNodeCannotPushLeaf may occur when attempting to push a leaf to a leaf node.
+	ErrLeafNodeCannotPushLeaf = errors.New("can't push a leaf to a leaf node")
+	// ErrZeroLevel occurs when the value of level is 0.
+	ErrZeroLevel = errors.New("level should be greater than 0")
+	// ErrZeroDepth occurs when the value of depth is 0.
+	ErrZeroDepth = errors.New("depth should be greater than 0")
 )

 // MerkleTreeNode is the interface for a Merkle tree.
@@ -11,9 +30,295 @@ type MerkleTreeNode interface {
 	// IsFull returns whether there is space left for deposits.
 	IsFull() bool
 	// Finalize marks deposits of the Merkle tree as finalized.
-	Finalize(deposits uint, depth uint) MerkleTreeNode
-	// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
-	GetFinalized(result [][32]byte) ([][32]byte, uint)
+	Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error)
+	// GetFinalized returns the number of deposits and a list of hashes of all the finalized nodes.
+	GetFinalized(result [][32]byte) (uint64, [][32]byte)
 	// PushLeaf adds a new leaf node at the next available Zero node.
-	PushLeaf(leaf [32]byte, deposits uint, depth uint) MerkleTreeNode
+	PushLeaf(leaf [32]byte, depth uint64) (MerkleTreeNode, error)
+
+	// Right represents the right child of a node.
+	Right() MerkleTreeNode
+	// Left represents the left child of a node.
+	Left() MerkleTreeNode
+}
+
+// create builds a new merkle tree
+func create(leaves [][32]byte, depth uint64) MerkleTreeNode {
+	length := uint64(len(leaves))
+	if length == 0 {
+		return &ZeroNode{depth: depth}
+	}
+	if depth == 0 {
+		return &LeafNode{hash: leaves[0]}
+	}
+	split := math.Min(math.PowerOf2(depth-1), length)
+	left := create(leaves[0:split], depth-1)
+	right := create(leaves[split:], depth-1)
+	return &InnerNode{left: left, right: right}
+}
+
+// fromSnapshotParts creates a new Merkle tree from a list of finalized leaves, number of deposits and specified depth.
+//
+//nolint:unused
+func fromSnapshotParts(finalized [][32]byte, deposits uint64, level uint64) (_ MerkleTreeNode, err error) {
+	if len(finalized) < 1 || deposits == 0 {
+		return &ZeroNode{
+			depth: level,
+		}, nil
+	}
+	if deposits == math.PowerOf2(level) {
+		return &FinalizedNode{
+			depositCount: deposits,
+			hash:         finalized[0],
+		}, nil
+	}
+	if level == 0 {
+		return &ZeroNode{}, ErrZeroLevel
+	}
+	node := InnerNode{}
+	if leftSubtree := math.PowerOf2(level - 1); deposits <= leftSubtree {
+		node.left, err = fromSnapshotParts(finalized, deposits, level-1)
+		if err != nil {
+			return &ZeroNode{}, err
+		}
+		node.right = &ZeroNode{depth: level - 1}
+	} else {
+		node.left = &FinalizedNode{
+			depositCount: leftSubtree,
+			hash:         finalized[0],
+		}
+		node.right, err = fromSnapshotParts(finalized[1:], deposits-leftSubtree, level-1)
+		if err != nil {
+			return &ZeroNode{}, err
+		}
+	}
+	return &node, nil
+}
+
+// generateProof returns a merkle proof and root
+//
+//nolint:unused
+func generateProof(tree MerkleTreeNode, index uint64, depth uint64) ([32]byte, [][32]byte) {
+	var proof [][32]byte
+	node := tree
+	for depth > 0 {
+		ithBit := (index >> (depth - 1)) & 0x1
+		if ithBit == 1 {
+			proof = append(proof, node.Left().GetRoot())
+			node = node.Right()
+		} else {
+			proof = append(proof, node.Right().GetRoot())
+			node = node.Left()
+		}
+		depth--
+	}
+	proof = slice.Reverse(proof)
+	return node.GetRoot(), proof
+}
+
+// FinalizedNode represents a finalized node and satisfies the MerkleTreeNode interface.
+type FinalizedNode struct {
+	depositCount uint64
+	hash         [32]byte
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (f *FinalizedNode) GetRoot() [32]byte {
+	return f.hash
+}
+
+// IsFull returns whether there is space left for deposits.
+// A FinalizedNode will always return true as by definition it
+// is full and deposits can't be added to it.
+func (_ *FinalizedNode) IsFull() bool {
+	return true
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (f *FinalizedNode) Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error) {
+	return f, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (f *FinalizedNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	return f.depositCount, append(result, f.hash)
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (_ *FinalizedNode) PushLeaf(_ [32]byte, _ uint64) (MerkleTreeNode, error) {
+	return nil, ErrFinalizedNodeCannotPushLeaf
+}
+
+// Right returns nil as a finalized node can't have any children.
+func (_ *FinalizedNode) Right() MerkleTreeNode {
+	return nil
+}
+
+// Left returns nil as a finalized node can't have any children.
+func (_ *FinalizedNode) Left() MerkleTreeNode {
+	return nil
+}
+
+// LeafNode represents a leaf node holding a deposit and satisfies the MerkleTreeNode interface.
+type LeafNode struct {
+	hash [32]byte
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (l *LeafNode) GetRoot() [32]byte {
+	return l.hash
+}
+
+// IsFull returns whether there is space left for deposits.
+// A LeafNode will always return true as it is the last node
+// in the tree and therefore can't have any deposits added to it.
+func (_ *LeafNode) IsFull() bool {
+	return true
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (l *LeafNode) Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error) {
+	return &FinalizedNode{1, l.hash}, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (_ *LeafNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	return 0, result
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (_ *LeafNode) PushLeaf(_ [32]byte, _ uint64) (MerkleTreeNode, error) {
+	return nil, ErrLeafNodeCannotPushLeaf
+}
+
+// Right returns nil as a leaf node is the last node and can't have any children.
+func (_ *LeafNode) Right() MerkleTreeNode {
+	return nil
+}
+
+// Left returns nil as a leaf node is the last node and can't have any children.
+func (_ *LeafNode) Left() MerkleTreeNode {
+	return nil
+}
+
+// InnerNode represents an inner node with two children and satisfies the MerkleTreeNode interface.
+type InnerNode struct {
+	left, right MerkleTreeNode
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (n *InnerNode) GetRoot() [32]byte {
+	left := n.left.GetRoot()
+	right := n.right.GetRoot()
+	return hash.Hash(append(left[:], right[:]...))
+}
+
+// IsFull returns whether there is space left for deposits.
+func (n *InnerNode) IsFull() bool {
+	return n.right.IsFull()
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (n *InnerNode) Finalize(depositsToFinalize uint64, depth uint64) (_ MerkleTreeNode, err error) {
+	deposits := math.PowerOf2(depth)
+	if deposits <= depositsToFinalize {
+		return &FinalizedNode{deposits, n.GetRoot()}, nil
+	}
+	if depth == 0 {
+		return &ZeroNode{}, ErrZeroDepth
+	}
+	n.left, err = n.left.Finalize(depositsToFinalize, depth-1)
+	if err != nil {
+		return &ZeroNode{}, err
+	}
+	if depositsToFinalize > deposits/2 {
+		remaining := depositsToFinalize - deposits/2
+		n.right, err = n.right.Finalize(remaining, depth-1)
+		if err != nil {
+			return &ZeroNode{}, err
+		}
+	}
+	return n, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (n *InnerNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	leftDeposits, result := n.left.GetFinalized(result)
+	rightDeposits, result := n.right.GetFinalized(result)
+	return leftDeposits + rightDeposits, result
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (n *InnerNode) PushLeaf(leaf [32]byte, depth uint64) (MerkleTreeNode, error) {
+	if !n.left.IsFull() {
+		left, err := n.left.PushLeaf(leaf, depth-1)
+		if err == nil {
+			n.left = left
+		} else {
+			return n, err
+		}
+	} else {
+		right, err := n.right.PushLeaf(leaf, depth-1)
+		if err == nil {
+			n.right = right
+		} else {
+			return n, err
+		}
+	}
+	return n, nil
+}
+
+// Right returns the child node on the right.
+func (n *InnerNode) Right() MerkleTreeNode {
+	return n.right
+}
+
+// Left returns the child node on the left.
+func (n *InnerNode) Left() MerkleTreeNode {
+	return n.left
+}
+
+// ZeroNode represents an empty node without a deposit and satisfies the MerkleTreeNode interface.
+type ZeroNode struct {
+	depth uint64
+}
+
+// GetRoot returns the root of the Merkle tree.
+func (z *ZeroNode) GetRoot() [32]byte {
+	if z.depth == DepositContractDepth {
+		return hash.Hash(append(Zerohashes[z.depth-1][:], Zerohashes[z.depth-1][:]...))
+	}
+	return Zerohashes[z.depth]
+}
+
+// IsFull returns wh   ether there is space left for deposits.
+// A ZeroNode will always return false as a ZeroNode is an empty node
+// that gets replaced by a deposit.
+func (_ *ZeroNode) IsFull() bool {
+	return false
+}
+
+// Finalize marks deposits of the Merkle tree as finalized.
+func (_ *ZeroNode) Finalize(depositsToFinalize uint64, depth uint64) (MerkleTreeNode, error) {
+	return nil, nil
+}
+
+// GetFinalized returns a list of hashes of all the finalized nodes and the number of deposits.
+func (_ *ZeroNode) GetFinalized(result [][32]byte) (uint64, [][32]byte) {
+	return 0, result
+}
+
+// PushLeaf adds a new leaf node at the next available zero node.
+func (_ *ZeroNode) PushLeaf(leaf [32]byte, depth uint64) (MerkleTreeNode, error) {
+	return create([][32]byte{leaf}, depth), nil
+}
+
+// Right returns nil as a zero node can't have any children.
+func (_ *ZeroNode) Right() MerkleTreeNode {
+	return nil
+}
+
+// Left returns nil as a zero node can't have any children.
+func (_ *ZeroNode) Left() MerkleTreeNode {
+	return nil
 }
--- a/beacon-chain/cache/depositsnapshot/zerohashes.gen.go
+++ b/beacon-chain/cache/depositsnapshot/zerohashes.gen.go
@@ -0,0 +1,69 @@
+// Code generated by gen_zerohashes. DO NOT EDIT.
+package depositsnapshot
+
+var Zerohashes = [][32]byte{
+	// 0000000000000000000000000000000000000000000000000000000000000000
+	{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
+	// f5a5fd42d16a20302798ef6ed309979b43003d2320d9f0e8ea9831a92759fb4b
+	{245, 165, 253, 66, 209, 106, 32, 48, 39, 152, 239, 110, 211, 9, 151, 155, 67, 0, 61, 35, 32, 217, 240, 232, 234, 152, 49, 169, 39, 89, 251, 75},
+	// db56114e00fdd4c1f85c892bf35ac9a89289aaecb1ebd0a96cde606a748b5d71
+	{219, 86, 17, 78, 0, 253, 212, 193, 248, 92, 137, 43, 243, 90, 201, 168, 146, 137, 170, 236, 177, 235, 208, 169, 108, 222, 96, 106, 116, 139, 93, 113},
+	// c78009fdf07fc56a11f122370658a353aaa542ed63e44c4bc15ff4cd105ab33c
+	{199, 128, 9, 253, 240, 127, 197, 106, 17, 241, 34, 55, 6, 88, 163, 83, 170, 165, 66, 237, 99, 228, 76, 75, 193, 95, 244, 205, 16, 90, 179, 60},
+	// 536d98837f2dd165a55d5eeae91485954472d56f246df256bf3cae19352a123c
+	{83, 109, 152, 131, 127, 45, 209, 101, 165, 93, 94, 234, 233, 20, 133, 149, 68, 114, 213, 111, 36, 109, 242, 86, 191, 60, 174, 25, 53, 42, 18, 60},
+	// 9efde052aa15429fae05bad4d0b1d7c64da64d03d7a1854a588c2cb8430c0d30
+	{158, 253, 224, 82, 170, 21, 66, 159, 174, 5, 186, 212, 208, 177, 215, 198, 77, 166, 77, 3, 215, 161, 133, 74, 88, 140, 44, 184, 67, 12, 13, 48},
+	// d88ddfeed400a8755596b21942c1497e114c302e6118290f91e6772976041fa1
+	{216, 141, 223, 238, 212, 0, 168, 117, 85, 150, 178, 25, 66, 193, 73, 126, 17, 76, 48, 46, 97, 24, 41, 15, 145, 230, 119, 41, 118, 4, 31, 161},
+	// 87eb0ddba57e35f6d286673802a4af5975e22506c7cf4c64bb6be5ee11527f2c
+	{135, 235, 13, 219, 165, 126, 53, 246, 210, 134, 103, 56, 2, 164, 175, 89, 117, 226, 37, 6, 199, 207, 76, 100, 187, 107, 229, 238, 17, 82, 127, 44},
+	// 26846476fd5fc54a5d43385167c95144f2643f533cc85bb9d16b782f8d7db193
+	{38, 132, 100, 118, 253, 95, 197, 74, 93, 67, 56, 81, 103, 201, 81, 68, 242, 100, 63, 83, 60, 200, 91, 185, 209, 107, 120, 47, 141, 125, 177, 147},
+	// 506d86582d252405b840018792cad2bf1259f1ef5aa5f887e13cb2f0094f51e1
+	{80, 109, 134, 88, 45, 37, 36, 5, 184, 64, 1, 135, 146, 202, 210, 191, 18, 89, 241, 239, 90, 165, 248, 135, 225, 60, 178, 240, 9, 79, 81, 225},
+	// ffff0ad7e659772f9534c195c815efc4014ef1e1daed4404c06385d11192e92b
+	{255, 255, 10, 215, 230, 89, 119, 47, 149, 52, 193, 149, 200, 21, 239, 196, 1, 78, 241, 225, 218, 237, 68, 4, 192, 99, 133, 209, 17, 146, 233, 43},
+	// 6cf04127db05441cd833107a52be852868890e4317e6a02ab47683aa75964220
+	{108, 240, 65, 39, 219, 5, 68, 28, 216, 51, 16, 122, 82, 190, 133, 40, 104, 137, 14, 67, 23, 230, 160, 42, 180, 118, 131, 170, 117, 150, 66, 32},
+	// b7d05f875f140027ef5118a2247bbb84ce8f2f0f1123623085daf7960c329f5f
+	{183, 208, 95, 135, 95, 20, 0, 39, 239, 81, 24, 162, 36, 123, 187, 132, 206, 143, 47, 15, 17, 35, 98, 48, 133, 218, 247, 150, 12, 50, 159, 95},
+	// df6af5f5bbdb6be9ef8aa618e4bf8073960867171e29676f8b284dea6a08a85e
+	{223, 106, 245, 245, 187, 219, 107, 233, 239, 138, 166, 24, 228, 191, 128, 115, 150, 8, 103, 23, 30, 41, 103, 111, 139, 40, 77, 234, 106, 8, 168, 94},
+	// b58d900f5e182e3c50ef74969ea16c7726c549757cc23523c369587da7293784
+	{181, 141, 144, 15, 94, 24, 46, 60, 80, 239, 116, 150, 158, 161, 108, 119, 38, 197, 73, 117, 124, 194, 53, 35, 195, 105, 88, 125, 167, 41, 55, 132},
+	// d49a7502ffcfb0340b1d7885688500ca308161a7f96b62df9d083b71fcc8f2bb
+	{212, 154, 117, 2, 255, 207, 176, 52, 11, 29, 120, 133, 104, 133, 0, 202, 48, 129, 97, 167, 249, 107, 98, 223, 157, 8, 59, 113, 252, 200, 242, 187},
+	// 8fe6b1689256c0d385f42f5bbe2027a22c1996e110ba97c171d3e5948de92beb
+	{143, 230, 177, 104, 146, 86, 192, 211, 133, 244, 47, 91, 190, 32, 39, 162, 44, 25, 150, 225, 16, 186, 151, 193, 113, 211, 229, 148, 141, 233, 43, 235},
+	// 8d0d63c39ebade8509e0ae3c9c3876fb5fa112be18f905ecacfecb92057603ab
+	{141, 13, 99, 195, 158, 186, 222, 133, 9, 224, 174, 60, 156, 56, 118, 251, 95, 161, 18, 190, 24, 249, 5, 236, 172, 254, 203, 146, 5, 118, 3, 171},
+	// 95eec8b2e541cad4e91de38385f2e046619f54496c2382cb6cacd5b98c26f5a4
+	{149, 238, 200, 178, 229, 65, 202, 212, 233, 29, 227, 131, 133, 242, 224, 70, 97, 159, 84, 73, 108, 35, 130, 203, 108, 172, 213, 185, 140, 38, 245, 164},
+	// f893e908917775b62bff23294dbbe3a1cd8e6cc1c35b4801887b646a6f81f17f
+	{248, 147, 233, 8, 145, 119, 117, 182, 43, 255, 35, 41, 77, 187, 227, 161, 205, 142, 108, 193, 195, 91, 72, 1, 136, 123, 100, 106, 111, 129, 241, 127},
+	// cddba7b592e3133393c16194fac7431abf2f5485ed711db282183c819e08ebaa
+	{205, 219, 167, 181, 146, 227, 19, 51, 147, 193, 97, 148, 250, 199, 67, 26, 191, 47, 84, 133, 237, 113, 29, 178, 130, 24, 60, 129, 158, 8, 235, 170},
+	// 8a8d7fe3af8caa085a7639a832001457dfb9128a8061142ad0335629ff23ff9c
+	{138, 141, 127, 227, 175, 140, 170, 8, 90, 118, 57, 168, 50, 0, 20, 87, 223, 185, 18, 138, 128, 97, 20, 42, 208, 51, 86, 41, 255, 35, 255, 156},
+	// feb3c337d7a51a6fbf00b9e34c52e1c9195c969bd4e7a0bfd51d5c5bed9c1167
+	{254, 179, 195, 55, 215, 165, 26, 111, 191, 0, 185, 227, 76, 82, 225, 201, 25, 92, 150, 155, 212, 231, 160, 191, 213, 29, 92, 91, 237, 156, 17, 103},
+	// e71f0aa83cc32edfbefa9f4d3e0174ca85182eec9f3a09f6a6c0df6377a510d7
+	{231, 31, 10, 168, 60, 195, 46, 223, 190, 250, 159, 77, 62, 1, 116, 202, 133, 24, 46, 236, 159, 58, 9, 246, 166, 192, 223, 99, 119, 165, 16, 215},
+	// 31206fa80a50bb6abe29085058f16212212a60eec8f049fecb92d8c8e0a84bc0
+	{49, 32, 111, 168, 10, 80, 187, 106, 190, 41, 8, 80, 88, 241, 98, 18, 33, 42, 96, 238, 200, 240, 73, 254, 203, 146, 216, 200, 224, 168, 75, 192},
+	// 21352bfecbeddde993839f614c3dac0a3ee37543f9b412b16199dc158e23b544
+	{33, 53, 43, 254, 203, 237, 221, 233, 147, 131, 159, 97, 76, 61, 172, 10, 62, 227, 117, 67, 249, 180, 18, 177, 97, 153, 220, 21, 142, 35, 181, 68},
+	// 619e312724bb6d7c3153ed9de791d764a366b389af13c58bf8a8d90481a46765
+	{97, 158, 49, 39, 36, 187, 109, 124, 49, 83, 237, 157, 231, 145, 215, 100, 163, 102, 179, 137, 175, 19, 197, 139, 248, 168, 217, 4, 129, 164, 103, 101},
+	// 7cdd2986268250628d0c10e385c58c6191e6fbe05191bcc04f133f2cea72c1c4
+	{124, 221, 41, 134, 38, 130, 80, 98, 141, 12, 16, 227, 133, 197, 140, 97, 145, 230, 251, 224, 81, 145, 188, 192, 79, 19, 63, 44, 234, 114, 193, 196},
+	// 848930bd7ba8cac54661072113fb278869e07bb8587f91392933374d017bcbe1
+	{132, 137, 48, 189, 123, 168, 202, 197, 70, 97, 7, 33, 19, 251, 39, 136, 105, 224, 123, 184, 88, 127, 145, 57, 41, 51, 55, 77, 1, 123, 203, 225},
+	// 8869ff2c22b28cc10510d9853292803328be4fb0e80495e8bb8d271f5b889636
+	{136, 105, 255, 44, 34, 178, 140, 193, 5, 16, 217, 133, 50, 146, 128, 51, 40, 190, 79, 176, 232, 4, 149, 232, 187, 141, 39, 31, 91, 136, 150, 54},
+	// b5fe28e79f1b850f8658246ce9b6a1e7b49fc06db7143e8fe0b4f2b0c5523a5c
+	{181, 254, 40, 231, 159, 27, 133, 15, 134, 88, 36, 108, 233, 182, 161, 231, 180, 159, 192, 109, 183, 20, 62, 143, 224, 180, 242, 176, 197, 82, 58, 92},
+	// 985e929f70af28d0bdd1a90a808f977f597c7c778c489e98d3bd8910d31ac0f7
+	{152, 94, 146, 159, 112, 175, 40, 208, 189, 209, 169, 10, 128, 143, 151, 127, 89, 124, 124, 119, 140, 72, 158, 152, 211, 189, 137, 16, 211, 26, 192, 247},
+}
--- a/beacon-chain/cache/payload_id.go
+++ b/beacon-chain/cache/payload_id.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"sync"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 )

@@ -27,7 +27,7 @@ func NewProposerPayloadIDsCache() *ProposerPayloadIDsCache {
 }

 // GetProposerPayloadIDs returns the proposer and  payload IDs for the given slot.
-func (f *ProposerPayloadIDsCache) GetProposerPayloadIDs(slot types.Slot, r [32]byte) (types.ValidatorIndex, [8]byte, bool) {
+func (f *ProposerPayloadIDsCache) GetProposerPayloadIDs(slot primitives.Slot, r [32]byte) (primitives.ValidatorIndex, [8]byte, bool) {
 	f.RLock()
 	defer f.RUnlock()
 	ids, ok := f.slotToProposerAndPayloadIDs[idKey(slot, r)]
@@ -40,11 +40,11 @@ func (f *ProposerPayloadIDsCache) GetProposerPayloadIDs(slot types.Slot, r [32]b
 	var pId [pIdLength]byte
 	copy(pId[:], b)

-	return types.ValidatorIndex(bytesutil.BytesToUint64BigEndian(vId)), pId, true
+	return primitives.ValidatorIndex(bytesutil.BytesToUint64BigEndian(vId)), pId, true
 }

 // SetProposerAndPayloadIDs sets the proposer and payload IDs for the given slot.
-func (f *ProposerPayloadIDsCache) SetProposerAndPayloadIDs(slot types.Slot, vId types.ValidatorIndex, pId [8]byte, r [32]byte) {
+func (f *ProposerPayloadIDsCache) SetProposerAndPayloadIDs(slot primitives.Slot, vId primitives.ValidatorIndex, pId [8]byte, r [32]byte) {
 	f.Lock()
 	defer f.Unlock()
 	var vIdBytes [vIdLength]byte
@@ -57,26 +57,26 @@ func (f *ProposerPayloadIDsCache) SetProposerAndPayloadIDs(slot types.Slot, vId
 	ids, ok := f.slotToProposerAndPayloadIDs[k]
 	// Ok to overwrite if the slot is already set but the cached payload ID is not set.
 	// This combats the re-org case where payload assignment could change at the start of the epoch.
-	byte8 := [vIdLength]byte{}
+	var byte8 [vIdLength]byte
 	if !ok || (ok && bytes.Equal(ids[vIdLength:], byte8[:])) {
 		f.slotToProposerAndPayloadIDs[k] = bs
 	}
 }

 // PrunePayloadIDs removes the payload id entries that's current than input slot.
-func (f *ProposerPayloadIDsCache) PrunePayloadIDs(slot types.Slot) {
+func (f *ProposerPayloadIDsCache) PrunePayloadIDs(slot primitives.Slot) {
 	f.Lock()
 	defer f.Unlock()

 	for k := range f.slotToProposerAndPayloadIDs {
-		s := types.Slot(bytesutil.BytesToUint64BigEndian(k[:8]))
+		s := primitives.Slot(bytesutil.BytesToUint64BigEndian(k[:8]))
 		if slot > s {
 			delete(f.slotToProposerAndPayloadIDs, k)
 		}
 	}
 }

-func idKey(slot types.Slot, r [32]byte) [40]byte {
+func idKey(slot primitives.Slot, r [32]byte) [40]byte {
 	var k [40]byte
 	copy(k[:], append(bytesutil.Uint64ToBytesBigEndian(uint64(slot)), r[:]...))
 	return k
--- a/beacon-chain/cache/payload_id_test.go
+++ b/beacon-chain/cache/payload_id_test.go
@@ -3,20 +3,20 @@ package cache
 import (
 	"testing"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 )

 func TestValidatorPayloadIDsCache_GetAndSaveValidatorPayloadIDs(t *testing.T) {
 	cache := NewProposerPayloadIDsCache()
-	r := [32]byte{}
+	var r [32]byte
 	i, p, ok := cache.GetProposerPayloadIDs(0, r)
 	require.Equal(t, false, ok)
-	require.Equal(t, types.ValidatorIndex(0), i)
+	require.Equal(t, primitives.ValidatorIndex(0), i)
 	require.Equal(t, [pIdLength]byte{}, p)

-	slot := types.Slot(1234)
-	vid := types.ValidatorIndex(34234324)
+	slot := primitives.Slot(1234)
+	vid := primitives.ValidatorIndex(34234324)
 	pid := [8]byte{1, 2, 3, 3, 7, 8, 7, 8}
 	r = [32]byte{1, 2, 3}
 	cache.SetProposerAndPayloadIDs(slot, vid, pid, r)
@@ -25,8 +25,8 @@ func TestValidatorPayloadIDsCache_GetAndSaveValidatorPayloadIDs(t *testing.T) {
 	require.Equal(t, vid, i)
 	require.Equal(t, pid, p)

-	slot = types.Slot(9456456)
-	vid = types.ValidatorIndex(6786745)
+	slot = primitives.Slot(9456456)
+	vid = primitives.ValidatorIndex(6786745)
 	r = [32]byte{4, 5, 6}
 	cache.SetProposerAndPayloadIDs(slot, vid, [pIdLength]byte{}, r)
 	i, p, ok = cache.GetProposerPayloadIDs(slot, r)
@@ -35,8 +35,8 @@ func TestValidatorPayloadIDsCache_GetAndSaveValidatorPayloadIDs(t *testing.T) {
 	require.Equal(t, [pIdLength]byte{}, p)

 	// reset cache without pid
-	slot = types.Slot(9456456)
-	vid = types.ValidatorIndex(11111)
+	slot = primitives.Slot(9456456)
+	vid = primitives.ValidatorIndex(11111)
 	r = [32]byte{7, 8, 9}
 	pid = [8]byte{3, 2, 3, 33, 72, 8, 7, 8}
 	cache.SetProposerAndPayloadIDs(slot, vid, pid, r)
@@ -49,12 +49,12 @@ func TestValidatorPayloadIDsCache_GetAndSaveValidatorPayloadIDs(t *testing.T) {
 	r = [32]byte{1, 2, 3}
 	i, p, ok = cache.GetProposerPayloadIDs(slot, r)
 	require.Equal(t, false, ok)
-	require.Equal(t, types.ValidatorIndex(0), i)
+	require.Equal(t, primitives.ValidatorIndex(0), i)
 	require.Equal(t, [pIdLength]byte{}, p)

 	// existing pid - no change in cache
-	slot = types.Slot(9456456)
-	vid = types.ValidatorIndex(11111)
+	slot = primitives.Slot(9456456)
+	vid = primitives.ValidatorIndex(11111)
 	r = [32]byte{7, 8, 9}
 	newPid := [8]byte{1, 2, 3, 33, 72, 8, 7, 1}
 	cache.SetProposerAndPayloadIDs(slot, vid, newPid, r)
@@ -67,6 +67,6 @@ func TestValidatorPayloadIDsCache_GetAndSaveValidatorPayloadIDs(t *testing.T) {
 	cache.PrunePayloadIDs(slot + 1)
 	i, p, ok = cache.GetProposerPayloadIDs(slot, r)
 	require.Equal(t, false, ok)
-	require.Equal(t, types.ValidatorIndex(0), i)
+	require.Equal(t, primitives.ValidatorIndex(0), i)
 	require.Equal(t, [pIdLength]byte{}, p)
 }
--- a/beacon-chain/cache/proposer_indices.go
+++ b/beacon-chain/cache/proposer_indices.go
@@ -7,7 +7,7 @@ import (

 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"k8s.io/client-go/tools/cache"
 )

@@ -76,7 +76,7 @@ func (c *ProposerIndicesCache) HasProposerIndices(r [32]byte) (bool, error) {
 }

 // ProposerIndices returns the proposer indices of a block root seed.
-func (c *ProposerIndicesCache) ProposerIndices(r [32]byte) ([]types.ValidatorIndex, error) {
+func (c *ProposerIndicesCache) ProposerIndices(r [32]byte) ([]primitives.ValidatorIndex, error) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	obj, exists, err := c.proposerIndicesCache.GetByKey(key(r))
--- a/beacon-chain/cache/proposer_indices_disabled.go
+++ b/beacon-chain/cache/proposer_indices_disabled.go
@@ -3,7 +3,7 @@
 // This file is used in fuzzer builds to bypass proposer indices caches.
 package cache

-import types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+import "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"

 // FakeProposerIndicesCache is a struct with 1 queue for looking up proposer indices by root.
 type FakeProposerIndicesCache struct {
@@ -21,7 +21,7 @@ func (c *FakeProposerIndicesCache) AddProposerIndices(p *ProposerIndices) error
 }

 // ProposerIndices returns the proposer indices of a block root seed.
-func (c *FakeProposerIndicesCache) ProposerIndices(r [32]byte) ([]types.ValidatorIndex, error) {
+func (c *FakeProposerIndicesCache) ProposerIndices(r [32]byte) ([]primitives.ValidatorIndex, error) {
 	return nil, nil
 }

--- a/beacon-chain/cache/proposer_indices_test.go
+++ b/beacon-chain/cache/proposer_indices_test.go
@@ -6,7 +6,7 @@ import (
 	"strconv"
 	"testing"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	"github.com/prysmaticlabs/prysm/v3/testing/assert"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
@@ -15,7 +15,7 @@ import (
 func TestProposerKeyFn_OK(t *testing.T) {
 	item := &ProposerIndices{
 		BlockRoot:       [32]byte{'A'},
-		ProposerIndices: []types.ValidatorIndex{1, 2, 3, 4, 5},
+		ProposerIndices: []primitives.ValidatorIndex{1, 2, 3, 4, 5},
 	}

 	k, err := proposerIndicesKeyFn(item)
@@ -51,7 +51,7 @@ func TestProposerCache_AddProposerIndicesList(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, true, has)

-	item := &ProposerIndices{BlockRoot: [32]byte{'B'}, ProposerIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6}}
+	item := &ProposerIndices{BlockRoot: [32]byte{'B'}, ProposerIndices: []primitives.ValidatorIndex{1, 2, 3, 4, 5, 6}}
 	require.NoError(t, cache.AddProposerIndices(item))

 	received, err = cache.ProposerIndices(item.BlockRoot)
--- a/beacon-chain/cache/proposer_indices_type.go
+++ b/beacon-chain/cache/proposer_indices_type.go
@@ -3,7 +3,7 @@ package cache
 import (
 	"errors"

-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 )

 // ErrNotProposerIndices will be returned when a cache object is not a pointer to
@@ -13,5 +13,5 @@ var ErrNotProposerIndices = errors.New("object is not a proposer indices struct"
 // ProposerIndices defines the cached struct for proposer indices.
 type ProposerIndices struct {
 	BlockRoot       [32]byte
-	ProposerIndices []types.ValidatorIndex
+	ProposerIndices []primitives.ValidatorIndex
 }
--- a/beacon-chain/cache/subnet_ids.go
+++ b/beacon-chain/cache/subnet_ids.go
@@ -8,7 +8,7 @@ import (
 	"github.com/patrickmn/go-cache"
 	lruwrpr "github.com/prysmaticlabs/prysm/v3/cache/lru"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/container/slice"
 )

@@ -37,7 +37,7 @@ func newSubnetIDs() *subnetIDs {
 }

 // AddAttesterSubnetID adds the subnet index for subscribing subnet for the attester of a given slot.
-func (s *subnetIDs) AddAttesterSubnetID(slot types.Slot, subnetID uint64) {
+func (s *subnetIDs) AddAttesterSubnetID(slot primitives.Slot, subnetID uint64) {
 	s.attesterLock.Lock()
 	defer s.attesterLock.Unlock()

@@ -50,7 +50,7 @@ func (s *subnetIDs) AddAttesterSubnetID(slot types.Slot, subnetID uint64) {
 }

 // GetAttesterSubnetIDs gets the subnet IDs for subscribed subnets for attesters of the slot.
-func (s *subnetIDs) GetAttesterSubnetIDs(slot types.Slot) []uint64 {
+func (s *subnetIDs) GetAttesterSubnetIDs(slot primitives.Slot) []uint64 {
 	s.attesterLock.RLock()
 	defer s.attesterLock.RUnlock()

@@ -65,7 +65,7 @@ func (s *subnetIDs) GetAttesterSubnetIDs(slot types.Slot) []uint64 {
 }

 // AddAggregatorSubnetID adds the subnet ID for subscribing subnet for the aggregator of a given slot.
-func (s *subnetIDs) AddAggregatorSubnetID(slot types.Slot, subnetID uint64) {
+func (s *subnetIDs) AddAggregatorSubnetID(slot primitives.Slot, subnetID uint64) {
 	s.aggregatorLock.Lock()
 	defer s.aggregatorLock.Unlock()

@@ -78,7 +78,7 @@ func (s *subnetIDs) AddAggregatorSubnetID(slot types.Slot, subnetID uint64) {
 }

 // GetAggregatorSubnetIDs gets the subnet IDs for subscribing subnet for aggregator of the slot.
-func (s *subnetIDs) GetAggregatorSubnetIDs(slot types.Slot) []uint64 {
+func (s *subnetIDs) GetAggregatorSubnetIDs(slot primitives.Slot) []uint64 {
 	s.aggregatorLock.RLock()
 	defer s.aggregatorLock.RUnlock()

--- a/beacon-chain/cache/subnet_ids_test.go
+++ b/beacon-chain/cache/subnet_ids_test.go
@@ -4,14 +4,14 @@ import (
 	"testing"

 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/testing/assert"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 )

 func TestSubnetIDsCache_RoundTrip(t *testing.T) {
 	c := newSubnetIDs()
-	slot := types.Slot(100)
+	slot := primitives.Slot(100)
 	committeeIDs := c.GetAggregatorSubnetIDs(slot)
 	assert.Equal(t, 0, len(committeeIDs), "Empty cache returned an object")

--- a/beacon-chain/cache/sync_committee.go
+++ b/beacon-chain/cache/sync_committee.go
@@ -8,7 +8,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	"k8s.io/client-go/tools/cache"
 )
@@ -40,13 +40,13 @@ type SyncCommitteeCache struct {
 // are cached where key is the validator index and the value is the `positionInCommittee` struct.
 type syncCommitteeIndexPosition struct {
 	currentSyncCommitteeRoot [32]byte
-	vIndexToPositionMap      map[types.ValidatorIndex]*positionInCommittee
+	vIndexToPositionMap      map[primitives.ValidatorIndex]*positionInCommittee
 }

 // Index position of individual validator of current period and next period sync committee.
 type positionInCommittee struct {
-	currentPeriod []types.CommitteeIndex
-	nextPeriod    []types.CommitteeIndex
+	currentPeriod []primitives.CommitteeIndex
+	nextPeriod    []primitives.CommitteeIndex
 }

 // NewSyncCommittee initializes and returns a new SyncCommitteeCache.
@@ -60,7 +60,7 @@ func NewSyncCommittee() *SyncCommitteeCache {
 // sync committee. If the input validator index has no assignment, an empty list will be returned.
 // If the input root does not exist in cache, `ErrNonExistingSyncCommitteeKey` is returned.
 // Manual checking of state for index position in state is recommended when `ErrNonExistingSyncCommitteeKey` is returned.
-func (s *SyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+func (s *SyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx primitives.ValidatorIndex) ([]primitives.CommitteeIndex, error) {
 	s.lock.RLock()
 	defer s.lock.RUnlock()

@@ -69,7 +69,7 @@ func (s *SyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx ty
 		return nil, err
 	}
 	if pos == nil {
-		return []types.CommitteeIndex{}, nil
+		return []primitives.CommitteeIndex{}, nil
 	}

 	return pos.currentPeriod, nil
@@ -79,7 +79,7 @@ func (s *SyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx ty
 // If the input validator index has no assignment, an empty list will be returned.
 // If the input root does not exist in cache, `ErrNonExistingSyncCommitteeKey` is returned.
 // Manual checking of state for index position in state is recommended when `ErrNonExistingSyncCommitteeKey` is returned.
-func (s *SyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+func (s *SyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx primitives.ValidatorIndex) ([]primitives.CommitteeIndex, error) {
 	s.lock.RLock()
 	defer s.lock.RUnlock()

@@ -88,7 +88,7 @@ func (s *SyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx types
 		return nil, err
 	}
 	if pos == nil {
-		return []types.CommitteeIndex{}, nil
+		return []primitives.CommitteeIndex{}, nil
 	}
 	return pos.nextPeriod, nil
 }
@@ -96,7 +96,7 @@ func (s *SyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx types
 // Helper function for `CurrentPeriodIndexPosition` and `NextPeriodIndexPosition` to return a mapping
 // of validator index to its index(s) position in the sync committee.
 func (s *SyncCommitteeCache) idxPositionInCommittee(
-	root [32]byte, valIdx types.ValidatorIndex,
+	root [32]byte, valIdx primitives.ValidatorIndex,
 ) (*positionInCommittee, error) {
 	obj, exists, err := s.cache.GetByKey(key(root))
 	if err != nil {
@@ -127,7 +127,7 @@ func (s *SyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoo
 	if err != nil {
 		return err
 	}
-	positionsMap := make(map[types.ValidatorIndex]*positionInCommittee)
+	positionsMap := make(map[primitives.ValidatorIndex]*positionInCommittee)
 	for i, pubkey := range csc.Pubkeys {
 		p := bytesutil.ToBytes48(pubkey)
 		validatorIndex, ok := st.ValidatorIndexByPubkey(p)
@@ -135,10 +135,10 @@ func (s *SyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoo
 			continue
 		}
 		if _, ok := positionsMap[validatorIndex]; !ok {
-			m := &positionInCommittee{currentPeriod: []types.CommitteeIndex{types.CommitteeIndex(i)}, nextPeriod: []types.CommitteeIndex{}}
+			m := &positionInCommittee{currentPeriod: []primitives.CommitteeIndex{primitives.CommitteeIndex(i)}, nextPeriod: []primitives.CommitteeIndex{}}
 			positionsMap[validatorIndex] = m
 		} else {
-			positionsMap[validatorIndex].currentPeriod = append(positionsMap[validatorIndex].currentPeriod, types.CommitteeIndex(i))
+			positionsMap[validatorIndex].currentPeriod = append(positionsMap[validatorIndex].currentPeriod, primitives.CommitteeIndex(i))
 		}
 	}

@@ -153,10 +153,10 @@ func (s *SyncCommitteeCache) UpdatePositionsInCommittee(syncCommitteeBoundaryRoo
 			continue
 		}
 		if _, ok := positionsMap[validatorIndex]; !ok {
-			m := &positionInCommittee{nextPeriod: []types.CommitteeIndex{types.CommitteeIndex(i)}, currentPeriod: []types.CommitteeIndex{}}
+			m := &positionInCommittee{nextPeriod: []primitives.CommitteeIndex{primitives.CommitteeIndex(i)}, currentPeriod: []primitives.CommitteeIndex{}}
 			positionsMap[validatorIndex] = m
 		} else {
-			positionsMap[validatorIndex].nextPeriod = append(positionsMap[validatorIndex].nextPeriod, types.CommitteeIndex(i))
+			positionsMap[validatorIndex].nextPeriod = append(positionsMap[validatorIndex].nextPeriod, primitives.CommitteeIndex(i))
 		}
 	}

--- a/beacon-chain/cache/sync_committee_disabled.go
+++ b/beacon-chain/cache/sync_committee_disabled.go
@@ -4,7 +4,7 @@ package cache

 import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 )

 // FakeSyncCommitteeCache is a fake `SyncCommitteeCache` to satisfy fuzzing.
@@ -17,12 +17,12 @@ func NewSyncCommittee() *FakeSyncCommitteeCache {
 }

 // CurrentEpochIndexPosition -- fake.
-func (s *FakeSyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+func (s *FakeSyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx primitives.ValidatorIndex) ([]primitives.CommitteeIndex, error) {
 	return nil, nil
 }

 // NextEpochIndexPosition -- fake.
-func (s *FakeSyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx types.ValidatorIndex) ([]types.CommitteeIndex, error) {
+func (s *FakeSyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx primitives.ValidatorIndex) ([]primitives.CommitteeIndex, error) {
 	return nil, nil
 }

--- a/beacon-chain/cache/sync_committee_head_state.go
+++ b/beacon-chain/cache/sync_committee_head_state.go
@@ -6,7 +6,7 @@ import (
 	lru "github.com/hashicorp/golang-lru"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	lruwrpr "github.com/prysmaticlabs/prysm/v3/cache/lru"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/runtime/version"
 )

@@ -23,7 +23,7 @@ func NewSyncCommitteeHeadState() *SyncCommitteeHeadStateCache {
 }

 // Put `slot` as key and `state` as value onto the cache.
-func (c *SyncCommitteeHeadStateCache) Put(slot types.Slot, st state.BeaconState) error {
+func (c *SyncCommitteeHeadStateCache) Put(slot primitives.Slot, st state.BeaconState) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	// Make sure that the provided state is non nil
@@ -41,7 +41,7 @@ func (c *SyncCommitteeHeadStateCache) Put(slot types.Slot, st state.BeaconState)
 }

 // Get `state` using `slot` as key. Return nil if nothing is found.
-func (c *SyncCommitteeHeadStateCache) Get(slot types.Slot) (state.BeaconState, error) {
+func (c *SyncCommitteeHeadStateCache) Get(slot primitives.Slot) (state.BeaconState, error) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	val, exists := c.cache.Get(slot)
@@ -52,9 +52,8 @@ func (c *SyncCommitteeHeadStateCache) Get(slot types.Slot) (state.BeaconState, e
 	if !ok {
 		return nil, ErrIncorrectType
 	}
-	switch st.Version() {
-	case version.Altair, version.Bellatrix:
-	default:
+	// Sync committee is not supported in phase 0.
+	if st.Version() == version.Phase0 {
 		return nil, ErrIncorrectType
 	}
 	return st, nil
--- a/beacon-chain/cache/sync_committee_head_state_test.go
+++ b/beacon-chain/cache/sync_committee_head_state_test.go
@@ -6,7 +6,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	state_native "github.com/prysmaticlabs/prysm/v3/beacon-chain/state/state-native"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 )
@@ -33,13 +33,20 @@ func TestSyncCommitteeHeadState(t *testing.T) {
 		},
 	})
 	require.NoError(t, err)
+	capellaState, err := state_native.InitializeFromProtoCapella(&ethpb.BeaconStateCapella{
+		Fork: &ethpb.Fork{
+			PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+			CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
+		},
+	})
+	require.NoError(t, err)
 	type put struct {
-		slot  types.Slot
+		slot  primitives.Slot
 		state state.BeaconState
 	}
 	tests := []struct {
 		name       string
-		key        types.Slot
+		key        primitives.Slot
 		put        *put
 		want       state.BeaconState
 		wantErr    bool
@@ -47,9 +54,9 @@ func TestSyncCommitteeHeadState(t *testing.T) {
 	}{
 		{
 			name: "putting error in",
-			key:  types.Slot(1),
+			key:  primitives.Slot(1),
 			put: &put{
-				slot:  types.Slot(1),
+				slot:  primitives.Slot(1),
 				state: nil,
 			},
 			wantPutErr: true,
@@ -57,9 +64,9 @@ func TestSyncCommitteeHeadState(t *testing.T) {
 		},
 		{
 			name: "putting invalid state in",
-			key:  types.Slot(1),
+			key:  primitives.Slot(1),
 			put: &put{
-				slot:  types.Slot(1),
+				slot:  primitives.Slot(1),
 				state: phase0State,
 			},
 			wantPutErr: true,
@@ -67,45 +74,54 @@ func TestSyncCommitteeHeadState(t *testing.T) {
 		},
 		{
 			name:    "not found when empty cache",
-			key:     types.Slot(1),
+			key:     primitives.Slot(1),
 			wantErr: true,
 		},
 		{
 			name: "not found when non-existent key in non-empty cache",
-			key:  types.Slot(2),
+			key:  primitives.Slot(2),
 			put: &put{
-				slot:  types.Slot(1),
+				slot:  primitives.Slot(1),
 				state: beaconState,
 			},
 			wantErr: true,
 		},
 		{
 			name: "found with key",
-			key:  types.Slot(1),
+			key:  primitives.Slot(1),
 			put: &put{
-				slot:  types.Slot(1),
+				slot:  primitives.Slot(1),
 				state: beaconState,
 			},
 			want: beaconState,
 		},
 		{
 			name: "not found when non-existent key in non-empty cache (bellatrix state)",
-			key:  types.Slot(2),
+			key:  primitives.Slot(2),
 			put: &put{
-				slot:  types.Slot(1),
+				slot:  primitives.Slot(1),
 				state: bellatrixState,
 			},
 			wantErr: true,
 		},
 		{
 			name: "found with key (bellatrix state)",
-			key:  types.Slot(100),
+			key:  primitives.Slot(100),
 			put: &put{
-				slot:  types.Slot(100),
+				slot:  primitives.Slot(100),
 				state: bellatrixState,
 			},
 			want: bellatrixState,
 		},
+		{
+			name: "found with key (capella state)",
+			key:  primitives.Slot(200),
+			put: &put{
+				slot:  primitives.Slot(200),
+				state: capellaState,
+			},
+			want: capellaState,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
--- a/beacon-chain/cache/sync_committee_test.go
+++ b/beacon-chain/cache/sync_committee_test.go
@@ -4,7 +4,7 @@ import (
 	"testing"

 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/cache"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 	"github.com/prysmaticlabs/prysm/v3/testing/util"
@@ -21,8 +21,8 @@ func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
 		name                 string
 		currentSyncCommittee *ethpb.SyncCommittee
 		nextSyncCommittee    *ethpb.SyncCommittee
-		currentSyncMap       map[types.ValidatorIndex][]types.CommitteeIndex
-		nextSyncMap          map[types.ValidatorIndex][]types.CommitteeIndex
+		currentSyncMap       map[primitives.ValidatorIndex][]primitives.CommitteeIndex
+		nextSyncMap          map[primitives.ValidatorIndex][]primitives.CommitteeIndex
 	}{
 		{
 			name: "only current epoch",
@@ -30,12 +30,12 @@ func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
 				pubKeys[1], pubKeys[2], pubKeys[3], pubKeys[2], pubKeys[2],
 			}),
 			nextSyncCommittee: util.ConvertToCommittee([][]byte{}),
-			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			currentSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {0},
 				2: {1, 3, 4},
 				3: {2},
 			},
-			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			nextSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {},
 				2: {},
 				3: {},
@@ -47,12 +47,12 @@ func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
 			nextSyncCommittee: util.ConvertToCommittee([][]byte{
 				pubKeys[1], pubKeys[2], pubKeys[3], pubKeys[2], pubKeys[2],
 			}),
-			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			currentSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {},
 				2: {},
 				3: {},
 			},
-			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			nextSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {0},
 				2: {1, 3, 4},
 				3: {2},
@@ -74,12 +74,12 @@ func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
 				pubKeys[4],
 				pubKeys[7],
 			}),
-			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			currentSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {0},
 				2: {1, 3, 4},
 				3: {2},
 			},
-			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			nextSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				7: {0, 4},
 				6: {1},
 				5: {2},
@@ -102,12 +102,12 @@ func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
 				pubKeys[2],
 				pubKeys[1],
 			}),
-			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			currentSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {0},
 				2: {1, 3, 4},
 				3: {2},
 			},
-			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			nextSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {1, 4},
 				2: {0, 3},
 				3: {2},
@@ -127,10 +127,10 @@ func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
 				pubKeys[100],
 				pubKeys[100],
 			}),
-			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			currentSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				100: {0, 1, 2, 3},
 			},
-			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			nextSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				100: {0, 1, 2, 3},
 			},
 		},
@@ -148,10 +148,10 @@ func TestSyncCommitteeCache_CanUpdateAndRetrieve(t *testing.T) {
 				pubKeys[100],
 				pubKeys[100],
 			}),
-			currentSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			currentSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {},
 			},
-			nextSyncMap: map[types.ValidatorIndex][]types.CommitteeIndex{
+			nextSyncMap: map[primitives.ValidatorIndex][]primitives.CommitteeIndex{
 				1: {},
 			},
 		},
--- a/beacon-chain/cache/sync_subnet_ids.go
+++ b/beacon-chain/cache/sync_subnet_ids.go
@@ -6,7 +6,7 @@ import (

 	"github.com/patrickmn/go-cache"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/container/slice"
 	"github.com/prysmaticlabs/prysm/v3/crypto/rand"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
@@ -29,7 +29,7 @@ func newSyncSubnetIDs() *syncSubnetIDs {
 }

 // GetSyncCommitteeSubnets retrieves the sync committee subnet and expiration time of that validator's subscription.
-func (s *syncSubnetIDs) GetSyncCommitteeSubnets(pubkey []byte, epoch types.Epoch) ([]uint64, types.Epoch, bool, time.Time) {
+func (s *syncSubnetIDs) GetSyncCommitteeSubnets(pubkey []byte, epoch primitives.Epoch) ([]uint64, primitives.Epoch, bool, time.Time) {
 	s.sCommiteeLock.RLock()
 	defer s.sCommiteeLock.RUnlock()

@@ -50,13 +50,13 @@ func (s *syncSubnetIDs) GetSyncCommitteeSubnets(pubkey []byte, epoch types.Epoch
 	// Index 0 was used to store validator's join epoch. We do not
 	// return it to the caller.
 	// Index 1 and beyond were used to store subnets.
-	return idxs[1:], types.Epoch(idxs[0]), ok, duration
+	return idxs[1:], primitives.Epoch(idxs[0]), ok, duration
 }

 // GetAllSubnets retrieves all the non-expired subscribed subnets of all the validators
 // in the cache. This method also takes the epoch as an argument to only retrieve
 // assignments for epochs that have happened.
-func (s *syncSubnetIDs) GetAllSubnets(currEpoch types.Epoch) []uint64 {
+func (s *syncSubnetIDs) GetAllSubnets(currEpoch primitives.Epoch) []uint64 {
 	s.sCommiteeLock.RLock()
 	defer s.sCommiteeLock.RUnlock()

@@ -79,7 +79,7 @@ func (s *syncSubnetIDs) GetAllSubnets(currEpoch types.Epoch) []uint64 {
 		// Check if the subnet is valid in the current epoch. If our
 		// join epoch is still in the future we skip retrieving the
 		// relevant committee index.
-		if types.Epoch(idxs[0]) > currEpoch {
+		if primitives.Epoch(idxs[0]) > currEpoch {
 			continue
 		}
 		// Ignore the first index as that represents the
@@ -92,7 +92,7 @@ func (s *syncSubnetIDs) GetAllSubnets(currEpoch types.Epoch) []uint64 {
 // AddSyncCommitteeSubnets adds the relevant committee for that particular validator along with its
 // expiration period. An Epoch argument here denotes the epoch from which the sync committee subnets
 // will be active.
-func (s *syncSubnetIDs) AddSyncCommitteeSubnets(pubkey []byte, epoch types.Epoch, comIndex []uint64, duration time.Duration) {
+func (s *syncSubnetIDs) AddSyncCommitteeSubnets(pubkey []byte, epoch primitives.Epoch, comIndex []uint64, duration time.Duration) {
 	s.sCommiteeLock.Lock()
 	defer s.sCommiteeLock.Unlock()
 	subComCount := params.BeaconConfig().SyncCommitteeSubnetCount
@@ -125,7 +125,7 @@ func (s *syncSubnetIDs) EmptyAllCaches() {

 // build a key composed of both the pubkey and epoch here. The epoch
 // here would be the 1st epoch of the sync committee period.
-func keyBuilder(pubkey []byte, epoch types.Epoch) string {
+func keyBuilder(pubkey []byte, epoch primitives.Epoch) string {
 	epochBytes := bytesutil.Bytes8(uint64(epoch))
 	return string(append(pubkey, epochBytes...))
 }
--- a/beacon-chain/core/altair/BUILD.bazel
+++ b/beacon-chain/core/altair/BUILD.bazel
@@ -14,13 +14,7 @@ go_library(
        "upgrade.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/v3/beacon-chain/core/altair",
-    visibility = [
-        "//beacon-chain:__subpackages__",
-        "//testing/endtoend/evaluators:__subpackages__",
-        "//testing/spectest:__subpackages__",
-        "//testing/util:__pkg__",
-        "//validator/client:__pkg__",
-    ],
+    visibility = ["//visibility:public"],
    deps = [
        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/epoch:go_default_library",
@@ -58,6 +52,7 @@ go_test(
        "deposit_test.go",
        "epoch_precompute_test.go",
        "epoch_spec_test.go",
+        "exports_test.go",
        "reward_test.go",
        "sync_committee_test.go",
        "transition_test.go",
--- a/beacon-chain/core/altair/attestation.go
+++ b/beacon-chain/core/altair/attestation.go
@@ -13,7 +13,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	consensusblocks "github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1/attestation"
 	"go.opencensus.io/trace"
@@ -24,7 +24,7 @@ import (
 func ProcessAttestationsNoVerifySignature(
 	ctx context.Context,
 	beaconState state.BeaconState,
-	b interfaces.SignedBeaconBlock,
+	b interfaces.ReadOnlySignedBeaconBlock,
 ) (state.BeaconState, error) {
 	if err := consensusblocks.BeaconBlockIsNil(b); err != nil {
 		return nil, err
@@ -82,27 +82,28 @@ func ProcessAttestationNoVerifySignature(
 // the proposer in state.
 //
 // Spec code:
-//     # Update epoch participation flags
-//    if data.target.epoch == get_current_epoch(state):
-//        epoch_participation = state.current_epoch_participation
-//    else:
-//        epoch_participation = state.previous_epoch_participation
 //
-//    proposer_reward_numerator = 0
-//    for index in get_attesting_indices(state, data, attestation.aggregation_bits):
-//        for flag_index, weight in enumerate(PARTICIPATION_FLAG_WEIGHTS):
-//            if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
-//                epoch_participation[index] = add_flag(epoch_participation[index], flag_index)
-//                proposer_reward_numerator += get_base_reward(state, index) * weight
+//	 # Update epoch participation flags
+//	if data.target.epoch == get_current_epoch(state):
+//	    epoch_participation = state.current_epoch_participation
+//	else:
+//	    epoch_participation = state.previous_epoch_participation
 //
-//    # Reward proposer
-//    proposer_reward_denominator = (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT) * WEIGHT_DENOMINATOR // PROPOSER_WEIGHT
-//    proposer_reward = Gwei(proposer_reward_numerator // proposer_reward_denominator)
-//    increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
+//	proposer_reward_numerator = 0
+//	for index in get_attesting_indices(state, data, attestation.aggregation_bits):
+//	    for flag_index, weight in enumerate(PARTICIPATION_FLAG_WEIGHTS):
+//	        if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
+//	            epoch_participation[index] = add_flag(epoch_participation[index], flag_index)
+//	            proposer_reward_numerator += get_base_reward(state, index) * weight
+//
+//	# Reward proposer
+//	proposer_reward_denominator = (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT) * WEIGHT_DENOMINATOR // PROPOSER_WEIGHT
+//	proposer_reward = Gwei(proposer_reward_numerator // proposer_reward_denominator)
+//	increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
 func SetParticipationAndRewardProposer(
 	ctx context.Context,
 	beaconState state.BeaconState,
-	targetEpoch types.Epoch,
+	targetEpoch primitives.Epoch,
 	indices []uint64,
 	participatedFlags map[uint8]bool, totalBalance uint64) (state.BeaconState, error) {
 	var proposerRewardNumerator uint64
@@ -157,12 +158,13 @@ func AddValidatorFlag(flag, flagPosition uint8) (uint8, error) {
 // EpochParticipation sets and returns the proposer reward numerator and epoch participation.
 //
 // Spec code:
-//    proposer_reward_numerator = 0
-//    for index in get_attesting_indices(state, data, attestation.aggregation_bits):
-//        for flag_index, weight in enumerate(PARTICIPATION_FLAG_WEIGHTS):
-//            if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
-//                epoch_participation[index] = add_flag(epoch_participation[index], flag_index)
-//                proposer_reward_numerator += get_base_reward(state, index) * weight
+//
+//	proposer_reward_numerator = 0
+//	for index in get_attesting_indices(state, data, attestation.aggregation_bits):
+//	    for flag_index, weight in enumerate(PARTICIPATION_FLAG_WEIGHTS):
+//	        if flag_index in participation_flag_indices and not has_flag(epoch_participation[index], flag_index):
+//	            epoch_participation[index] = add_flag(epoch_participation[index], flag_index)
+//	            proposer_reward_numerator += get_base_reward(state, index) * weight
 func EpochParticipation(beaconState state.BeaconState, indices []uint64, epochParticipation []byte, participatedFlags map[uint8]bool, totalBalance uint64) (uint64, []byte, error) {
 	cfg := params.BeaconConfig()
 	sourceFlagIndex := cfg.TimelySourceFlagIndex
@@ -173,7 +175,7 @@ func EpochParticipation(beaconState state.BeaconState, indices []uint64, epochPa
 		if index >= uint64(len(epochParticipation)) {
 			return 0, nil, fmt.Errorf("index %d exceeds participation length %d", index, len(epochParticipation))
 		}
-		br, err := BaseRewardWithTotalBalance(beaconState, types.ValidatorIndex(index), totalBalance)
+		br, err := BaseRewardWithTotalBalance(beaconState, primitives.ValidatorIndex(index), totalBalance)
 		if err != nil {
 			return 0, nil, err
 		}
@@ -218,9 +220,10 @@ func EpochParticipation(beaconState state.BeaconState, indices []uint64, epochPa
 // RewardProposer rewards proposer by increasing proposer's balance with input reward numerator and calculated reward denominator.
 //
 // Spec code:
-//    proposer_reward_denominator = (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT) * WEIGHT_DENOMINATOR // PROPOSER_WEIGHT
-//    proposer_reward = Gwei(proposer_reward_numerator // proposer_reward_denominator)
-//    increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
+//
+//	proposer_reward_denominator = (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT) * WEIGHT_DENOMINATOR // PROPOSER_WEIGHT
+//	proposer_reward = Gwei(proposer_reward_numerator // proposer_reward_denominator)
+//	increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
 func RewardProposer(ctx context.Context, beaconState state.BeaconState, proposerRewardNumerator uint64) error {
 	cfg := params.BeaconConfig()
 	d := (cfg.WeightDenominator - cfg.ProposerWeight) * cfg.WeightDenominator / cfg.ProposerWeight
@@ -238,32 +241,33 @@ func RewardProposer(ctx context.Context, beaconState state.BeaconState, proposer
 //
 // Spec code:
 // def get_attestation_participation_flag_indices(state: BeaconState,
-//                                               data: AttestationData,
-//                                               inclusion_delay: uint64) -> Sequence[int]:
-//    """
-//    Return the flag indices that are satisfied by an attestation.
-//    """
-//    if data.target.epoch == get_current_epoch(state):
-//        justified_checkpoint = state.current_justified_checkpoint
-//    else:
-//        justified_checkpoint = state.previous_justified_checkpoint
 //
-//    # Matching roots
-//    is_matching_source = data.source == justified_checkpoint
-//    is_matching_target = is_matching_source and data.target.root == get_block_root(state, data.target.epoch)
-//    is_matching_head = is_matching_target and data.beacon_block_root == get_block_root_at_slot(state, data.slot)
-//    assert is_matching_source
+//	                                           data: AttestationData,
+//	                                           inclusion_delay: uint64) -> Sequence[int]:
+//	"""
+//	Return the flag indices that are satisfied by an attestation.
+//	"""
+//	if data.target.epoch == get_current_epoch(state):
+//	    justified_checkpoint = state.current_justified_checkpoint
+//	else:
+//	    justified_checkpoint = state.previous_justified_checkpoint
 //
-//    participation_flag_indices = []
-//    if is_matching_source and inclusion_delay <= integer_squareroot(SLOTS_PER_EPOCH):
-//        participation_flag_indices.append(TIMELY_SOURCE_FLAG_INDEX)
-//    if is_matching_target and inclusion_delay <= SLOTS_PER_EPOCH:
-//        participation_flag_indices.append(TIMELY_TARGET_FLAG_INDEX)
-//    if is_matching_head and inclusion_delay == MIN_ATTESTATION_INCLUSION_DELAY:
-//        participation_flag_indices.append(TIMELY_HEAD_FLAG_INDEX)
+//	# Matching roots
+//	is_matching_source = data.source == justified_checkpoint
+//	is_matching_target = is_matching_source and data.target.root == get_block_root(state, data.target.epoch)
+//	is_matching_head = is_matching_target and data.beacon_block_root == get_block_root_at_slot(state, data.slot)
+//	assert is_matching_source
 //
-//    return participation_flag_indices
-func AttestationParticipationFlagIndices(beaconState state.BeaconState, data *ethpb.AttestationData, delay types.Slot) (map[uint8]bool, error) {
+//	participation_flag_indices = []
+//	if is_matching_source and inclusion_delay <= integer_squareroot(SLOTS_PER_EPOCH):
+//	    participation_flag_indices.append(TIMELY_SOURCE_FLAG_INDEX)
+//	if is_matching_target and inclusion_delay <= SLOTS_PER_EPOCH:
+//	    participation_flag_indices.append(TIMELY_TARGET_FLAG_INDEX)
+//	if is_matching_head and inclusion_delay == MIN_ATTESTATION_INCLUSION_DELAY:
+//	    participation_flag_indices.append(TIMELY_HEAD_FLAG_INDEX)
+//
+//	return participation_flag_indices
+func AttestationParticipationFlagIndices(beaconState state.BeaconState, data *ethpb.AttestationData, delay primitives.Slot) (map[uint8]bool, error) {
 	currEpoch := time.CurrentEpoch(beaconState)
 	var justifiedCheckpt *ethpb.Checkpoint
 	if data.Target.Epoch == currEpoch {
@@ -304,9 +308,10 @@ func AttestationParticipationFlagIndices(beaconState state.BeaconState, data *et
 // MatchingStatus returns the matching statues for attestation data's source target and head.
 //
 // Spec code:
-//    is_matching_source = data.source == justified_checkpoint
-//    is_matching_target = is_matching_source and data.target.root == get_block_root(state, data.target.epoch)
-//    is_matching_head = is_matching_target and data.beacon_block_root == get_block_root_at_slot(state, data.slot)
+//
+//	is_matching_source = data.source == justified_checkpoint
+//	is_matching_target = is_matching_source and data.target.root == get_block_root(state, data.target.epoch)
+//	is_matching_head = is_matching_target and data.beacon_block_root == get_block_root_at_slot(state, data.slot)
 func MatchingStatus(beaconState state.BeaconState, data *ethpb.AttestationData, cp *ethpb.Checkpoint) (matchedSrc, matchedTgt, matchedHead bool, err error) {
 	matchedSrc = attestation.CheckPointIsEqual(data.Source, cp)

--- a/beacon-chain/core/altair/attestation_test.go
+++ b/beacon-chain/core/altair/attestation_test.go
@@ -16,7 +16,7 @@ import (
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
 	"github.com/prysmaticlabs/prysm/v3/consensus-types/blocks"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v3/math"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
@@ -256,7 +256,7 @@ func TestProcessAttestationNoVerify_SourceTargetHead(t *testing.T) {
 		},
 		AggregationBits: aggBits,
 	}
-	zeroSig := [96]byte{}
+	var zeroSig [96]byte
 	att.Signature = zeroSig[:]

 	ckp := beaconState.CurrentJustifiedCheckpoint()
@@ -443,7 +443,7 @@ func TestSetParticipationAndRewardProposer(t *testing.T) {
 		indices             []uint64
 		epochParticipation  []byte
 		participatedFlags   map[uint8]bool
-		epoch               types.Epoch
+		epoch               primitives.Epoch
 		wantedBalance       uint64
 		wantedParticipation []byte
 	}{
@@ -634,7 +634,7 @@ func TestAttestationParticipationFlagIndices(t *testing.T) {
 		name                 string
 		inputState           state.BeaconState
 		inputData            *ethpb.AttestationData
-		inputDelay           types.Slot
+		inputDelay           primitives.Slot
 		participationIndices map[uint8]bool
 	}{
 		{
@@ -658,7 +658,7 @@ func TestAttestationParticipationFlagIndices(t *testing.T) {
 				Source: &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]},
 				Target: &ethpb.Checkpoint{},
 			},
-			inputDelay: types.Slot(math.IntegerSquareRoot(uint64(cfg.SlotsPerEpoch)) - 1),
+			inputDelay: primitives.Slot(math.IntegerSquareRoot(uint64(cfg.SlotsPerEpoch)) - 1),
 			participationIndices: map[uint8]bool{
 				sourceFlagIndex: true,
 			},
@@ -672,7 +672,7 @@ func TestAttestationParticipationFlagIndices(t *testing.T) {
 				Source: &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]},
 				Target: &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]},
 			},
-			inputDelay: types.Slot(math.IntegerSquareRoot(uint64(cfg.SlotsPerEpoch)) - 1),
+			inputDelay: primitives.Slot(math.IntegerSquareRoot(uint64(cfg.SlotsPerEpoch)) - 1),
 			participationIndices: map[uint8]bool{
 				sourceFlagIndex: true,
 				targetFlagIndex: true,
--- a/beacon-chain/core/altair/block.go
+++ b/beacon-chain/core/altair/block.go
@@ -9,7 +9,6 @@ import (
 	p2pType "github.com/prysmaticlabs/prysm/v3/beacon-chain/p2p/types"
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
@@ -20,83 +19,106 @@ import (
 //
 // Spec code:
 // def process_sync_aggregate(state: BeaconState, sync_aggregate: SyncAggregate) -> None:
-//    # Verify sync committee aggregate signature signing over the previous slot block root
-//    committee_pubkeys = state.current_sync_committee.pubkeys
-//    participant_pubkeys = [pubkey for pubkey, bit in zip(committee_pubkeys, sync_aggregate.sync_committee_bits) if bit]
-//    previous_slot = max(state.slot, Slot(1)) - Slot(1)
-//    domain = get_domain(state, DOMAIN_SYNC_COMMITTEE, compute_epoch_at_slot(previous_slot))
-//    signing_root = compute_signing_root(get_block_root_at_slot(state, previous_slot), domain)
-//    assert eth2_fast_aggregate_verify(participant_pubkeys, signing_root, sync_aggregate.sync_committee_signature)
 //
-//    # Compute participant and proposer rewards
-//    total_active_increments = get_total_active_balance(state) // EFFECTIVE_BALANCE_INCREMENT
-//    total_base_rewards = Gwei(get_base_reward_per_increment(state) * total_active_increments)
-//    max_participant_rewards = Gwei(total_base_rewards * SYNC_REWARD_WEIGHT // WEIGHT_DENOMINATOR // SLOTS_PER_EPOCH)
-//    participant_reward = Gwei(max_participant_rewards // SYNC_COMMITTEE_SIZE)
-//    proposer_reward = Gwei(participant_reward * PROPOSER_WEIGHT // (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT))
+//	# Verify sync committee aggregate signature signing over the previous slot block root
+//	committee_pubkeys = state.current_sync_committee.pubkeys
+//	participant_pubkeys = [pubkey for pubkey, bit in zip(committee_pubkeys, sync_aggregate.sync_committee_bits) if bit]
+//	previous_slot = max(state.slot, Slot(1)) - Slot(1)
+//	domain = get_domain(state, DOMAIN_SYNC_COMMITTEE, compute_epoch_at_slot(previous_slot))
+//	signing_root = compute_signing_root(get_block_root_at_slot(state, previous_slot), domain)
+//	assert eth2_fast_aggregate_verify(participant_pubkeys, signing_root, sync_aggregate.sync_committee_signature)
 //
-//    # Apply participant and proposer rewards
-//    all_pubkeys = [v.pubkey for v in state.validators]
-//    committee_indices = [ValidatorIndex(all_pubkeys.index(pubkey)) for pubkey in state.current_sync_committee.pubkeys]
-//    for participant_index, participation_bit in zip(committee_indices, sync_aggregate.sync_committee_bits):
-//        if participation_bit:
-//            increase_balance(state, participant_index, participant_reward)
-//            increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
-//        else:
-//            decrease_balance(state, participant_index, participant_reward)
-func ProcessSyncAggregate(ctx context.Context, s state.BeaconState, sync *ethpb.SyncAggregate) (state.BeaconState, error) {
-	votedKeys, votedIndices, didntVoteIndices, err := FilterSyncCommitteeVotes(s, sync)
+//	# Compute participant and proposer rewards
+//	total_active_increments = get_total_active_balance(state) // EFFECTIVE_BALANCE_INCREMENT
+//	total_base_rewards = Gwei(get_base_reward_per_increment(state) * total_active_increments)
+//	max_participant_rewards = Gwei(total_base_rewards * SYNC_REWARD_WEIGHT // WEIGHT_DENOMINATOR // SLOTS_PER_EPOCH)
+//	participant_reward = Gwei(max_participant_rewards // SYNC_COMMITTEE_SIZE)
+//	proposer_reward = Gwei(participant_reward * PROPOSER_WEIGHT // (WEIGHT_DENOMINATOR - PROPOSER_WEIGHT))
+//
+//	# Apply participant and proposer rewards
+//	all_pubkeys = [v.pubkey for v in state.validators]
+//	committee_indices = [ValidatorIndex(all_pubkeys.index(pubkey)) for pubkey in state.current_sync_committee.pubkeys]
+//	for participant_index, participation_bit in zip(committee_indices, sync_aggregate.sync_committee_bits):
+//	    if participation_bit:
+//	        increase_balance(state, participant_index, participant_reward)
+//	        increase_balance(state, get_beacon_proposer_index(state), proposer_reward)
+//	    else:
+//	        decrease_balance(state, participant_index, participant_reward)
+func ProcessSyncAggregate(ctx context.Context, s state.BeaconState, sync *ethpb.SyncAggregate) (state.BeaconState, uint64, error) {
+	s, votedKeys, reward, err := processSyncAggregate(ctx, s, sync)
 	if err != nil {
-		return nil, errors.Wrap(err, "could not filter sync committee votes")
+		return nil, 0, errors.Wrap(err, "could not filter sync committee votes")
 	}

 	if err := VerifySyncCommitteeSig(s, votedKeys, sync.SyncCommitteeSignature); err != nil {
-		return nil, errors.Wrap(err, "could not verify sync committee signature")
+		return nil, 0, errors.Wrap(err, "could not verify sync committee signature")
 	}
-
-	return ApplySyncRewardsPenalties(ctx, s, votedIndices, didntVoteIndices)
+	return s, reward, nil
 }

-// FilterSyncCommitteeVotes filters the validator public keys and indices for the ones that voted and didn't vote.
-func FilterSyncCommitteeVotes(s state.BeaconState, sync *ethpb.SyncAggregate) (
-	votedKeys []bls.PublicKey,
-	votedIndices []types.ValidatorIndex,
-	didntVoteIndices []types.ValidatorIndex,
-	err error) {
+// processSyncAggregate applies all the logic in the spec function `process_sync_aggregate` except
+// verifying the BLS signatures. It returns the modified beacons state, the list of validators'
+// public keys that voted (for future signature verification) and the proposer reward for including
+// sync aggregate messages.
+func processSyncAggregate(ctx context.Context, s state.BeaconState, sync *ethpb.SyncAggregate) (
+	state.BeaconState,
+	[]bls.PublicKey,
+	uint64,
+	error) {
 	currentSyncCommittee, err := s.CurrentSyncCommittee()
 	if err != nil {
-		return nil, nil, nil, err
+		return nil, nil, 0, err
 	}
 	if currentSyncCommittee == nil {
-		return nil, nil, nil, errors.New("nil current sync committee in state")
+		return nil, nil, 0, errors.New("nil current sync committee in state")
 	}
 	committeeKeys := currentSyncCommittee.Pubkeys
 	if sync.SyncCommitteeBits.Len() > uint64(len(committeeKeys)) {
-		return nil, nil, nil, errors.New("bits length exceeds committee length")
+		return nil, nil, 0, errors.New("bits length exceeds committee length")
 	}
-	votedKeys = make([]bls.PublicKey, 0, len(committeeKeys))
-	votedIndices = make([]types.ValidatorIndex, 0, len(committeeKeys))
-	didntVoteIndices = make([]types.ValidatorIndex, 0) // No allocation. Expect most votes.
+	votedKeys := make([]bls.PublicKey, 0, len(committeeKeys))

+	activeBalance, err := helpers.TotalActiveBalance(s)
+	if err != nil {
+		return nil, nil, 0, err
+	}
+	proposerReward, participantReward, err := SyncRewards(activeBalance)
+	if err != nil {
+		return nil, nil, 0, err
+	}
+	proposerIndex, err := helpers.BeaconProposerIndex(ctx, s)
+	if err != nil {
+		return nil, nil, 0, err
+	}
+
+	earnedProposerReward := uint64(0)
 	for i := uint64(0); i < sync.SyncCommitteeBits.Len(); i++ {
 		vIdx, exists := s.ValidatorIndexByPubkey(bytesutil.ToBytes48(committeeKeys[i]))
 		// Impossible scenario.
 		if !exists {
-			return nil, nil, nil, errors.New("validator public key does not exist in state")
+			return nil, nil, 0, errors.New("validator public key does not exist in state")
 		}

 		if sync.SyncCommitteeBits.BitAt(i) {
 			pubKey, err := bls.PublicKeyFromBytes(committeeKeys[i])
 			if err != nil {
-				return nil, nil, nil, err
+				return nil, nil, 0, err
 			}
 			votedKeys = append(votedKeys, pubKey)
-			votedIndices = append(votedIndices, vIdx)
+			if err := helpers.IncreaseBalance(s, vIdx, participantReward); err != nil {
+				return nil, nil, 0, err
+			}
+			earnedProposerReward += proposerReward
 		} else {
-			didntVoteIndices = append(didntVoteIndices, vIdx)
+			if err := helpers.DecreaseBalance(s, vIdx, participantReward); err != nil {
+				return nil, nil, 0, err
+			}
 		}
 	}
-	return
+	if err := helpers.IncreaseBalance(s, proposerIndex, earnedProposerReward); err != nil {
+		return nil, nil, 0, err
+	}
+	return s, votedKeys, earnedProposerReward, err
 }

 // VerifySyncCommitteeSig verifies sync committee signature `syncSig` is valid with respect to public keys `syncKeys`.
@@ -125,43 +147,6 @@ func VerifySyncCommitteeSig(s state.BeaconState, syncKeys []bls.PublicKey, syncS
 	return nil
 }

-// ApplySyncRewardsPenalties applies rewards and penalties for proposer and sync committee participants.
-func ApplySyncRewardsPenalties(ctx context.Context, s state.BeaconState, votedIndices, didntVoteIndices []types.ValidatorIndex) (state.BeaconState, error) {
-	activeBalance, err := helpers.TotalActiveBalance(s)
-	if err != nil {
-		return nil, err
-	}
-	proposerReward, participantReward, err := SyncRewards(activeBalance)
-	if err != nil {
-		return nil, err
-	}
-
-	// Apply sync committee rewards.
-	earnedProposerReward := uint64(0)
-	for _, index := range votedIndices {
-		if err := helpers.IncreaseBalance(s, index, participantReward); err != nil {
-			return nil, err
-		}
-		earnedProposerReward += proposerReward
-	}
-	// Apply proposer rewards.
-	proposerIndex, err := helpers.BeaconProposerIndex(ctx, s)
-	if err != nil {
-		return nil, err
-	}
-	if err := helpers.IncreaseBalance(s, proposerIndex, earnedProposerReward); err != nil {
-		return nil, err
-	}
-	// Apply sync committee penalties.
-	for _, index := range didntVoteIndices {
-		if err := helpers.DecreaseBalance(s, index, participantReward); err != nil {
-			return nil, err
-		}
-	}
-
-	return s, nil
-}
-
 // SyncRewards returns the proposer reward and the sync participant reward given the total active balance in state.
 func SyncRewards(activeBalance uint64) (proposerReward, participantReward uint64, err error) {
 	cfg := params.BeaconConfig()
--- a/beacon-chain/core/altair/block_test.go
+++ b/beacon-chain/core/altair/block_test.go
@@ -13,10 +13,11 @@ import (
 	p2pType "github.com/prysmaticlabs/prysm/v3/beacon-chain/p2p/types"
 	fieldparams "github.com/prysmaticlabs/prysm/v3/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	"github.com/prysmaticlabs/prysm/v3/crypto/bls"
 	"github.com/prysmaticlabs/prysm/v3/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v3/testing/assert"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
 	"github.com/prysmaticlabs/prysm/v3/testing/util"
 	"github.com/prysmaticlabs/prysm/v3/time/slots"
@@ -53,16 +54,18 @@ func TestProcessSyncCommittee_PerfectParticipation(t *testing.T) {
 		SyncCommitteeSignature: aggregatedSig,
 	}

-	beaconState, err = altair.ProcessSyncAggregate(context.Background(), beaconState, syncAggregate)
+	var reward uint64
+	beaconState, reward, err = altair.ProcessSyncAggregate(context.Background(), beaconState, syncAggregate)
 	require.NoError(t, err)
+	assert.Equal(t, uint64(72192), reward)

 	// Use a non-sync committee index to compare profitability.
-	syncCommittee := make(map[types.ValidatorIndex]bool)
+	syncCommittee := make(map[primitives.ValidatorIndex]bool)
 	for _, index := range indices {
 		syncCommittee[index] = true
 	}
-	nonSyncIndex := types.ValidatorIndex(params.BeaconConfig().MaxValidatorsPerCommittee + 1)
-	for i := types.ValidatorIndex(0); uint64(i) < params.BeaconConfig().MaxValidatorsPerCommittee; i++ {
+	nonSyncIndex := primitives.ValidatorIndex(params.BeaconConfig().MaxValidatorsPerCommittee + 1)
+	for i := primitives.ValidatorIndex(0); uint64(i) < params.BeaconConfig().MaxValidatorsPerCommittee; i++ {
 		if !syncCommittee[i] {
 			nonSyncIndex = i
 			break
@@ -127,7 +130,7 @@ func TestProcessSyncCommittee_MixParticipation_BadSignature(t *testing.T) {
 		SyncCommitteeSignature: aggregatedSig,
 	}

-	_, err = altair.ProcessSyncAggregate(context.Background(), beaconState, syncAggregate)
+	_, _, err = altair.ProcessSyncAggregate(context.Background(), beaconState, syncAggregate)
 	require.ErrorContains(t, "invalid sync committee signature", err)
 }

@@ -164,11 +167,40 @@ func TestProcessSyncCommittee_MixParticipation_GoodSignature(t *testing.T) {
 		SyncCommitteeSignature: aggregatedSig,
 	}

-	_, err = altair.ProcessSyncAggregate(context.Background(), beaconState, syncAggregate)
+	_, _, err = altair.ProcessSyncAggregate(context.Background(), beaconState, syncAggregate)
 	require.NoError(t, err)
 }

-func TestProcessSyncCommittee_FilterSyncCommitteeVotes(t *testing.T) {
+// This is a regression test #11696
+func TestProcessSyncCommittee_DontPrecompute(t *testing.T) {
+	beaconState, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().MaxValidatorsPerCommittee)
+	require.NoError(t, beaconState.SetSlot(1))
+	committee, err := altair.NextSyncCommittee(context.Background(), beaconState)
+	require.NoError(t, err)
+	committeeKeys := committee.Pubkeys
+	committeeKeys[1] = committeeKeys[0]
+	require.NoError(t, beaconState.SetCurrentSyncCommittee(committee))
+	idx, ok := beaconState.ValidatorIndexByPubkey(bytesutil.ToBytes48(committeeKeys[0]))
+	require.Equal(t, true, ok)
+
+	syncBits := bitfield.NewBitvector512()
+	for i := range syncBits {
+		syncBits[i] = 0xFF
+	}
+	syncBits.SetBitAt(0, false)
+	syncAggregate := &ethpb.SyncAggregate{
+		SyncCommitteeBits: syncBits,
+	}
+	require.NoError(t, beaconState.UpdateBalancesAtIndex(idx, 0))
+	st, votedKeys, _, err := altair.ProcessSyncAggregateEported(context.Background(), beaconState, syncAggregate)
+	require.NoError(t, err)
+	require.Equal(t, 511, len(votedKeys))
+	require.DeepEqual(t, committeeKeys[0], votedKeys[0].Marshal())
+	balances := st.Balances()
+	require.Equal(t, uint64(988), balances[idx])
+}
+
+func TestProcessSyncCommittee_processSyncAggregate(t *testing.T) {
 	beaconState, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().MaxValidatorsPerCommittee)
 	require.NoError(t, beaconState.SetSlot(1))
 	committee, err := altair.NextSyncCommittee(context.Background(), beaconState)
@@ -183,25 +215,40 @@ func TestProcessSyncCommittee_FilterSyncCommitteeVotes(t *testing.T) {
 		SyncCommitteeBits: syncBits,
 	}

-	votedKeys, votedIndices, didntVoteIndices, err := altair.FilterSyncCommitteeVotes(beaconState, syncAggregate)
+	st, votedKeys, _, err := altair.ProcessSyncAggregateEported(context.Background(), beaconState, syncAggregate)
 	require.NoError(t, err)
 	votedMap := make(map[[fieldparams.BLSPubkeyLength]byte]bool)
 	for _, key := range votedKeys {
 		votedMap[bytesutil.ToBytes48(key.Marshal())] = true
 	}
 	require.Equal(t, int(syncBits.Len()/2), len(votedKeys))
-	require.Equal(t, int(syncBits.Len()/2), len(votedIndices))
-	require.Equal(t, int(syncBits.Len()/2), len(didntVoteIndices))
+
+	currentSyncCommittee, err := st.CurrentSyncCommittee()
+	require.NoError(t, err)
+	committeeKeys := currentSyncCommittee.Pubkeys
+	balances := st.Balances()
+
+	proposerIndex, err := helpers.BeaconProposerIndex(context.Background(), beaconState)
+	require.NoError(t, err)

 	for i := 0; i < len(syncBits); i++ {
 		if syncBits.BitAt(uint64(i)) {
-			pk := beaconState.PubkeyAtIndex(votedIndices[i])
+			pk := bytesutil.ToBytes48(committeeKeys[i])
 			require.DeepEqual(t, true, votedMap[pk])
+			idx, ok := st.ValidatorIndexByPubkey(pk)
+			require.Equal(t, true, ok)
+			require.Equal(t, uint64(32000000988), balances[idx])
 		} else {
-			pk := beaconState.PubkeyAtIndex(didntVoteIndices[i])
+			pk := bytesutil.ToBytes48(committeeKeys[i])
 			require.DeepEqual(t, false, votedMap[pk])
+			idx, ok := st.ValidatorIndexByPubkey(pk)
+			require.Equal(t, true, ok)
+			if idx != proposerIndex {
+				require.Equal(t, uint64(31999999012), balances[idx])
+			}
 		}
 	}
+	require.Equal(t, uint64(32000035108), balances[proposerIndex])
 }

 func Test_VerifySyncCommitteeSig(t *testing.T) {
@@ -240,22 +287,6 @@ func Test_VerifySyncCommitteeSig(t *testing.T) {
 	require.NoError(t, altair.VerifySyncCommitteeSig(beaconState, pks, aggregatedSig))
 }

-func Test_ApplySyncRewardsPenalties(t *testing.T) {
-	beaconState, _ := util.DeterministicGenesisStateAltair(t, params.BeaconConfig().MaxValidatorsPerCommittee)
-	beaconState, err := altair.ApplySyncRewardsPenalties(context.Background(), beaconState,
-		[]types.ValidatorIndex{0, 1}, // voted
-		[]types.ValidatorIndex{2, 3}) // didn't vote
-	require.NoError(t, err)
-	balances := beaconState.Balances()
-	require.Equal(t, uint64(32000000988), balances[0])
-	require.Equal(t, balances[0], balances[1])
-	require.Equal(t, uint64(31999999012), balances[2])
-	require.Equal(t, balances[2], balances[3])
-	proposerIndex, err := helpers.BeaconProposerIndex(context.Background(), beaconState)
-	require.NoError(t, err)
-	require.Equal(t, uint64(32000000282), balances[proposerIndex])
-}
-
 func Test_SyncRewards(t *testing.T) {
 	tests := []struct {
 		name                  string
--- a/beacon-chain/core/altair/epoch_precompute.go
+++ b/beacon-chain/core/altair/epoch_precompute.go
@@ -68,9 +68,10 @@ func InitializePrecomputeValidators(ctx context.Context, beaconState state.Beaco
 // For fully inactive validators and perfect active validators, the effect is the same as before Altair.
 // For a validator is inactive and the chain fails to finalize, the inactivity score increases by a fixed number, the total loss after N epochs is proportional to N**2/2.
 // For imperfectly active validators. The inactivity score's behavior is specified by this function:
-//    If a validator fails to submit an attestation with the correct target, their inactivity score goes up by 4.
-//    If they successfully submit an attestation with the correct source and target, their inactivity score drops by 1
-//    If the chain has recently finalized, each validator's score drops by 16.
+//
+//	If a validator fails to submit an attestation with the correct target, their inactivity score goes up by 4.
+//	If they successfully submit an attestation with the correct source and target, their inactivity score drops by 1
+//	If the chain has recently finalized, each validator's score drops by 16.
 func ProcessInactivityScores(
 	ctx context.Context,
 	beaconState state.BeaconState,
@@ -132,12 +133,13 @@ func ProcessInactivityScores(
 // it also tracks and updates epoch attesting balances.
 // Spec code:
 // if epoch == get_current_epoch(state):
-//        epoch_participation = state.current_epoch_participation
-//    else:
-//        epoch_participation = state.previous_epoch_participation
-//    active_validator_indices = get_active_validator_indices(state, epoch)
-//    participating_indices = [i for i in active_validator_indices if has_flag(epoch_participation[i], flag_index)]
-//    return set(filter(lambda index: not state.validators[index].slashed, participating_indices))
+//
+//	    epoch_participation = state.current_epoch_participation
+//	else:
+//	    epoch_participation = state.previous_epoch_participation
+//	active_validator_indices = get_active_validator_indices(state, epoch)
+//	participating_indices = [i for i in active_validator_indices if has_flag(epoch_participation[i], flag_index)]
+//	return set(filter(lambda index: not state.validators[index].slashed, participating_indices))
 func ProcessEpochParticipation(
 	ctx context.Context,
 	beaconState state.BeaconState,
--- a/beacon-chain/core/altair/epoch_precompute_test.go
+++ b/beacon-chain/core/altair/epoch_precompute_test.go
@@ -9,7 +9,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
 	state_native "github.com/prysmaticlabs/prysm/v3/beacon-chain/state/state-native"
 	"github.com/prysmaticlabs/prysm/v3/config/params"
-	types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
 	ethpb "github.com/prysmaticlabs/prysm/v3/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/v3/testing/assert"
 	"github.com/prysmaticlabs/prysm/v3/testing/require"
@@ -330,7 +330,7 @@ func TestProcessInactivityScores_CanProcessInactivityLeak(t *testing.T) {
 	require.NoError(t, err)
 	defaultScore := uint64(5)
 	require.NoError(t, s.SetInactivityScores([]uint64{defaultScore, defaultScore, defaultScore, defaultScore}))
-	require.NoError(t, s.SetSlot(params.BeaconConfig().SlotsPerEpoch*types.Slot(params.BeaconConfig().MinEpochsToInactivityPenalty+2)))
+	require.NoError(t, s.SetSlot(params.BeaconConfig().SlotsPerEpoch*primitives.Slot(params.BeaconConfig().MinEpochsToInactivityPenalty+2)))
 	validators, balance, err := InitializePrecomputeValidators(context.Background(), s)
 	require.NoError(t, err)
 	validators, _, err = ProcessEpochParticipation(context.Background(), s, balance, validators)
--- a/Show More
+++ b/Show More
				`@@ -0,0 +1 @@`
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