diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 10bba8c..f4a94dd 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,30 +10,34 @@ jobs:
   build:
     strategy:
       matrix:
-        os: [ubuntu-20.04]
+        # macos-13 is x86_64, and macos-14 is arm64
+        os: [ubuntu-22.04, macos-13, macos-14]
       fail-fast: false
     runs-on: ${{ matrix.os }}
     name: build.py ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: true
-      - name: Install toolchain (Ubuntu)
-        if: runner.os == 'Linux'
-        run: |
-          sudo apt-get install -y gcc-arm-none-eabi libnewlib-arm-none-eabi
-          sudo apt-get install -y cmake
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+      - uses: carlosperate/arm-none-eabi-gcc-action@v1
+        with:
+          release: 10.3-2021.10
+      - name: Install CMake v3.22 via PyPI
+        run: python -m pip install cmake==3.28.3
       - name: Check Versions
         run: |
           arm-none-eabi-gcc --version
           cmake --version
-      - name: Build
-        run: |
-          make -C lib/micropython/mpy-cross -j2
-          cd src
-          make -j2
+          python --version
+      - name: Build mpy-cross
+        run: make -C lib/micropython/mpy-cross -j2
+      - name: Build MicroPython
+        run: make -C src -j2
       - name: Upload hex file
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
-          name: MICROBIT-MICROPYTHON-${{ github.sha }}.hex
+          name: MICROBIT-MICROPYTHON-${{ github.sha }}-${{ matrix.os }}.hex
           path: src/MICROBIT.hex
diff --git a/lib/codal b/lib/codal
index 3864ea2..871d0fc 160000
--- a/lib/codal
+++ b/lib/codal
@@ -1 +1 @@
-Subproject commit 3864ea2e452f710ac3e09598996edee4df72a5bf
+Subproject commit 871d0fccaf385a57f7cd2c2d61c644ec04107914