diff --git a/.github/actions/nimbus-build-system/action.yml b/.github/actions/nimbus-build-system/action.yml
deleted file mode 100644
index b78c5596..00000000
--- a/.github/actions/nimbus-build-system/action.yml
+++ /dev/null
@@ -1,169 +0,0 @@
-# Adapted from:
-# https://github.com/status-im/nimbus-eth2/blob/stable/.github/workflows/ci.yml
-
-name: Setup Nimbus Build System
-inputs:
-  os:
-    description: "Operating system to build for"
-    required: true
-  cpu:
-    description: "CPU to build for"
-    default: "amd64"
-  nim_branch:
-    description: "Nim version"
-    default: "version-1-6"
-  shell:
-    description: "Shell to run commands in"
-    default: "bash --noprofile --norc -e -o pipefail"
-runs:
-  using: "composite"
-  steps:
-    - name: APT (Linux amd64)
-      if: inputs.os == 'linux' && inputs.cpu == 'amd64'
-      shell: ${{ inputs.shell }} {0}
-      run: |
-        sudo apt-fast update -qq
-        sudo DEBIAN_FRONTEND='noninteractive' apt-fast install \
-          --no-install-recommends -yq lcov
-
-    - name: APT (Linux i386)
-      if: inputs.os == 'linux' && inputs.cpu == 'i386'
-      shell: ${{ inputs.shell }} {0}
-      run: |
-        sudo dpkg --add-architecture i386
-        sudo apt-fast update -qq
-        sudo DEBIAN_FRONTEND='noninteractive' apt-fast install \
-          --no-install-recommends -yq gcc-multilib g++-multilib
-
-    - name: Homebrew (macOS)
-      if: inputs.os == 'macos'
-      shell: ${{ inputs.shell }} {0}
-      run: |
-        brew install libomp
-
-    - name: MSYS2 (Windows amd64)
-      if: inputs.os == 'windows' && inputs.cpu == 'amd64'
-      uses: msys2/setup-msys2@v2
-      with:
-        msystem: UCRT64
-        install: >
-          base-devel
-          git
-          mingw-w64-ucrt-x86_64-toolchain
-          mingw-w64-ucrt-x86_64-cmake
-          mingw-w64-ucrt-x86_64-ntldd-git
-
-    - name: MSYS2 (Windows i386)
-      if: inputs.os == 'windows' && inputs.cpu == 'i386'
-      uses: msys2/setup-msys2@v2
-      with:
-        msystem: MINGW32
-        install: >
-          base-devel
-          git
-          mingw-w64-i686-toolchain
-          mingw-w64-i686-cmake
-          mingw-w64-i686-ntldd-git
-
-    - name: Derive environment variables
-      shell: ${{ inputs.shell }} {0}
-      run: |
-        quote () {
-          local quoted=${1//\'/\'\\\'\'};
-          printf "'%s'" "$quoted"
-        }
-
-        if [[ '${{ inputs.cpu }}' == 'amd64' ]]; then
-          PLATFORM=x64
-        else
-          PLATFORM=x86
-        fi
-        echo "PLATFORM=${PLATFORM}" >> ${GITHUB_ENV}
-
-        # Stack usage on Linux amd64
-        if [[ '${{ inputs.os }}' == 'linux' && '${{ inputs.cpu }}' == 'amd64' ]]; then
-          NIMFLAGS="${NIMFLAGS} -d:limitStackUsage"
-          echo "NIMFLAGS=${NIMFLAGS}" >> $GITHUB_ENV
-        fi
-
-        # Disable ADX on Linux i386
-        if [[ '${{ inputs.os }}' == 'linux' && '${{ inputs.cpu }}' == 'i386' ]]; then
-          CFLAGS="${CFLAGS} -m32 -mno-adx"
-          echo "CFLAGS=${CFLAGS}" >> ${GITHUB_ENV}
-          CXXFLAGS="${CXXFLAGS} -m32 -mno-adx"
-          echo "CXXFLAGS=${CXXFLAGS}" >> ${GITHUB_ENV}
-          mkdir -p external/bin
-          cat << EOF > external/bin/gcc
-        #!/bin/bash
-        exec $(which gcc) -m32 -mno-adx "\$@"
-        EOF
-          cat << EOF > external/bin/g++
-        #!/bin/bash
-        exec $(which g++) -m32 -mno-adx "\$@"
-        EOF
-          chmod 755 external/bin/gcc external/bin/g++
-          echo "$(pwd)/external/bin" >> ${GITHUB_PATH}
-          # --passC:'-m32 -mno-adx' is redundant but harmless, and can be
-          # helpful when reviewing build output with increased verbosity
-          NIMFLAGS="${NIMFLAGS} $(quote "--passC:'-m32 -mno-adx' -d:LeopardCmakeFlags='-DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=$(pwd)/external/bin/gcc -DCMAKE_CXX_COMPILER=$(pwd)/external/bin/g++'")"
-          echo "NIMFLAGS=${NIMFLAGS}" >> $GITHUB_ENV
-        fi
-
-        # Disable ADX on Windows i386
-        if [[ '${{ inputs.os }}' == 'windows' && '${{ inputs.cpu }}' == 'i386' ]]; then
-          CFLAGS="${CFLAGS} -mno-adx"
-          echo "CFLAGS=${CFLAGS}" >> ${GITHUB_ENV}
-          CXXFLAGS="${CXXFLAGS} -mno-adx"
-          echo "CXXFLAGS=${CXXFLAGS}" >> ${GITHUB_ENV}
-          NIMFLAGS="${NIMFLAGS} --passC:-mno-adx"
-          echo "NIMFLAGS=${NIMFLAGS}" >> $GITHUB_ENV
-        fi
-
-        # Enable OpenMP on macOS
-        if [[ '${{ inputs.os }}' == 'macos' ]]; then
-          libomp_lib_dir="$(brew --prefix)/opt/libomp/lib"
-          # See https://github.com/actions/virtual-environments/pull/5819
-          llvm_dir="$(ls -d $(brew --prefix)/opt/llvm* | tail -1)"
-          llvm_bin_dir="${llvm_dir}/bin"
-          llvm_lib_dir="${llvm_dir}/lib"
-          echo "${llvm_bin_dir}" >> ${GITHUB_PATH}
-          echo "LDFLAGS=${LDFLAGS} -L${libomp_lib_dir} -L${llvm_lib_dir} -Wl,-rpath,${llvm_lib_dir}" >> ${GITHUB_ENV}
-          NIMFLAGS="${NIMFLAGS} $(quote "-d:LeopardCmakeFlags='-DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=${llvm_bin_dir}/clang -DCMAKE_CXX_COMPILER=${llvm_bin_dir}/clang++' -d:LeopardExtraCompilerlags='-fopenmp' -d:LeopardExtraLinkerFlags='-fopenmp -L${libomp_lib_dir}'")"
-          echo "NIMFLAGS=${NIMFLAGS}" >> $GITHUB_ENV
-        fi
-
-        # Use all available CPUs for build process
-        ncpu=""
-        case '${{ inputs.os }}' in
-        'linux')
-          ncpu=$(nproc)
-          ;;
-        'macos')
-          ncpu=$(sysctl -n hw.ncpu)
-          ;;
-        'windows')
-          ncpu=${NUMBER_OF_PROCESSORS}
-          ;;
-        esac
-        [[ -z "$ncpu" || $ncpu -le 0 ]] && ncpu=1
-        echo "ncpu=${ncpu}" >> ${GITHUB_ENV}
-
-    - name: Restore Nim toolchain binaries from cache
-      id: nim-cache
-      uses: actions/cache@v3
-      with:
-        path: NimBinaries
-        key: ${{ inputs.os }}-${{ inputs.cpu }}-nim-${{ inputs.nim_branch }}-cache-${{ env.cache_nonce }}-${{ github.run_id }}
-        restore-keys: ${{ inputs.os }}-${{ inputs.cpu }}-nim-${{ inputs.nim_branch }}-cache-${{ env.cache_nonce }}
-
-    - name: Set NIM_COMMIT
-      shell: ${{ inputs.shell }} {0}
-      run: echo "NIM_COMMIT=${{ inputs.nim_branch }}" >> ${GITHUB_ENV}
-
-    - name: Build Nim and Codex dependencies
-      shell: ${{ inputs.shell }} {0}
-      run: |
-        make -j${ncpu} CI_CACHE=NimBinaries ARCH_OVERRIDE=${PLATFORM} QUICK_AND_DIRTY_COMPILER=1 update
-        echo
-        ./env.sh nim --version
-
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4fddce10..96472c13 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,102 +5,30 @@ on:
       - main
   pull_request:
   workflow_dispatch:
-env:
-  cache_nonce: 0 # Allows for easily busting actions/cache caches
+permissions: {}
 jobs:
-  build:
+  test:
+    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [linux, macos, windows]
-        include:
-          - os: linux
-            builder: ubuntu-latest
-            shell: bash --noprofile --norc -e -o pipefail
-          - os: macos
-            builder: macos-latest
-            shell: bash --noprofile --norc -e -o pipefail
-          - os: windows
-            builder: windows-latest
-            shell: msys2
-
-    defaults:
-      run:
-        shell: ${{ matrix.shell }} {0}
-
-    name: '${{ matrix.os }}'
-    runs-on: ${{ matrix.builder }}
-    timeout-minutes: 80
+        os: [ubuntu-latest, macOS-latest, windows-latest]
     steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-        with:
-          submodules: recursive
-
-      - name: Setup Nimbus Build System
-        uses: ./.github/actions/nimbus-build-system
-        with:
-          os: ${{ matrix.os }}
-          shell: ${{ matrix.shell }}
-
-      - name: Unit tests
-        run: make -j${ncpu} test
-
-      - name: Start Ethereum node with Codex contracts
-        working-directory: vendor/dagger-contracts
-        run: |
-          if [[ '${{ matrix.os }}' == 'windows' ]]; then
-            export PATH="${PATH}:/c/program files/nodejs"
-          fi
-          npm install
-          npm start &
-
-      - name: Contract tests
-        run: make -j${ncpu} testContracts
-
-      - name: Integration tests
-        run: make -j${ncpu} testIntegration
-
-  coverage:
-    continue-on-error: true
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-        with:
-          submodules: recursive
-
-      - name: Setup Nimbus Build System
-        uses: ./.github/actions/nimbus-build-system
-        with:
-          os: linux
-
-      - name: Generate coverage data
-        run: make -j${ncpu} coverage
-        shell: bash
-
-      - name: Upload coverage data to Codecov
-        uses: codecov/codecov-action@v3
-        with:
-          directory: ./coverage/
-          fail_ci_if_error: true
-          files: ./coverage/coverage.f.info
-          flags: unittests
-          name: codecov-umbrella
-          verbose: true
-
-  nim_1_2:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-        with:
-          submodules: recursive
-
-      - name: Setup Nimbus Build System
-        uses: ./.github/actions/nimbus-build-system
-        with:
-          os: linux
-          nim_branch: version-1-2
-
-      - name: Unit tests
-        run: make -j${ncpu} test
+    - uses: actions/checkout@v2
+    - uses: iffy/install-nim@v4
+      with:
+        version: binary:stable
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    - name: Install dependencies
+      run: nimble install -d -y
+    - name: Unit Tests
+      run: nimble test
+    - name: Integration Tests
+      run: |
+        cd vendor/dagger-contracts
+        git submodule update --init .
+        npm install
+        npm start &
+        cd ../../
+        nimble testContracts
+        nimble testIntegration