diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index a6521e7ca..ef357caae 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -36,7 +36,7 @@ jobs:
       # Note the current convention is to use the -S and -B options here to specify source 
       # and build directories, but this is only available with CMake 3.13 and higher.  
       # The CMake binaries on the Github Actions machines are (as of this writing) 3.12
-      run: cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE
+      run: cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DPICO_SDK_TESTS_ENABLED=1
 
     - name: Get core count
       id: core_count
diff --git a/.github/workflows/multi-gcc.yml b/.github/workflows/multi-gcc.yml
new file mode 100644
index 000000000..54d2880cf
--- /dev/null
+++ b/.github/workflows/multi-gcc.yml
@@ -0,0 +1,154 @@
+name: Multi GCC
+on: [workflow_dispatch, push, pull_request]
+
+jobs:
+  build:
+    if: github.repository_owner == 'raspberrypi'
+    runs-on: [self-hosted, Linux, X64]
+
+    steps:
+    - name: Clean workspace
+      run: |
+        echo "Cleaning up previous run"
+        rm -rf "${{ github.workspace }}"
+        mkdir -p "${{ github.workspace }}"
+
+    - name: Checkout repo
+      uses: actions/checkout@v2
+
+    - name: Checkout submodules
+      run: git submodule update --init
+
+    - name: Get core count
+      id: core_count
+      run : cat /proc/cpuinfo  | grep processor | wc -l
+
+    - name: GCC 6.2.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-6_2-2016q4 -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 6.2.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-6_2-2016q4 -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 6.3.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-6-2017-q2-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 6.3.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-6-2017-q2-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 7.2.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-7-2017-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 7.2.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-7-2017-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 7.3.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-7-2018-q2-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 7.3.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-7-2018-q2-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 8.2.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-8-2018-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 8.2.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-8-2018-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 8.3.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-8-2019-q3-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 8.3.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-8-2019-q3-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 9.2.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-9-2019-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 9.2.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-9-2019-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 9.3.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-9-2020-q2-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 9.3.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-9-2020-q2-update -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 10.2.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-10-2020-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 10.2.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-10-2020-q4-major -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 10.3.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-10.3-2021.10 -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 10.3.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-none-eabi-10.3-2021.10 -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 11.2.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-11.2-2022.02-x86_64-arm-none-eabi -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 11.2.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/gcc-arm-11.2-2022.02-x86_64-arm-none-eabi -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 11.3.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/arm-gnu-toolchain-11.3.rel1-x86_64-arm-none-eabi -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 11.3.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/arm-gnu-toolchain-11.3.rel1-x86_64-arm-none-eabi -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 12.2.1 Debug
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Debug -DPICO_TOOLCHAIN_PATH=/opt/arm/arm-gnu-toolchain-12.2.rel1-x86_64-arm-none-eabi -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
+
+    - name: GCC 12.2.1 Release
+      if: always()
+      shell: bash
+      run: cd ${{github.workspace}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE=Release -DPICO_TOOLCHAIN_PATH=/opt/arm/arm-gnu-toolchain-12.2.rel1-x86_64-arm-none-eabi -DPICO_BOARD=pico_w; make -j ${{steps.core_count.outputs.output}}
diff --git a/.github/workflows/scripts/generate_multi_gcc_workflow.py b/.github/workflows/scripts/generate_multi_gcc_workflow.py
new file mode 100755
index 000000000..4e9d742a3
--- /dev/null
+++ b/.github/workflows/scripts/generate_multi_gcc_workflow.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+
+import os
+from collections import OrderedDict
+import subprocess
+import re
+
+toolchain_dir = "/opt/arm"
+toolchains = os.listdir(toolchain_dir)
+
+gcc_versions = OrderedDict()
+
+for toolchain in toolchains:
+    fullpath = os.path.join(toolchain_dir, toolchain)
+    gcc_path = os.path.join(fullpath, "bin/arm-none-eabi-gcc")
+    version = subprocess.run([gcc_path, "--version"], capture_output=True)
+    stdout = version.stdout.decode('utf-8')
+    stderr = version.stderr.decode('utf-8')
+    assert(len(stderr) == 0)
+    # Version should be on first line
+    version_line = stdout.split("\n")[0]
+    m = re.search("(\d+\.\d+\.\d+)", version_line)
+    assert(m is not None)
+    version = m.group(1)
+
+    if version in gcc_versions:
+        raise Exception("Already have version {} in versions current path {}, this path {}".format(version, gcc_versions[version], fullpath))
+
+    gcc_versions[version] = fullpath
+
+# Sort by major version
+gcc_versions_sorted = OrderedDict(sorted(gcc_versions.items(), key=lambda item: int(item[0].replace(".", ""))))
+
+
+# Create output
+output = '''
+name: Multi GCC
+on: [workflow_dispatch, push, pull_request]
+
+jobs:
+  build:
+    if: github.repository_owner == 'raspberrypi'
+    runs-on: [self-hosted, Linux, X64]
+
+    steps:
+    - name: Clean workspace
+      run: |
+        echo "Cleaning up previous run"
+        rm -rf "${{ github.workspace }}"
+        mkdir -p "${{ github.workspace }}"
+
+    - name: Checkout repo
+      uses: actions/checkout@v2
+
+    - name: Checkout submodules
+      run: git submodule update --init
+
+    - name: Get core count
+      id: core_count
+      run : cat /proc/cpuinfo  | grep processor | wc -l
+'''
+
+for gcc_version, toolchain_path in gcc_versions_sorted.items():
+    for build_type in ["Debug", "Release"]:
+        output += "\n"
+        output += "    - name: GCC {} {}\n".format(gcc_version, build_type)
+        output += "      if: always()\n"
+        output += "      shell: bash\n"
+        output += "      run: cd ${{{{github.workspace}}}}; mkdir -p build; rm -rf build/*; cd build; cmake ../ -DPICO_SDK_TESTS_ENABLED=1 -DCMAKE_BUILD_TYPE={} -DPICO_TOOLCHAIN_PATH={} -DPICO_BOARD=pico_w; make -j ${{{{steps.core_count.outputs.output}}}}\n".format(build_type, toolchain_path)
+
+print(output)