diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f8c0c30a5b0132..3649ae6c207b0a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -193,16 +193,28 @@ jobs:
     needs: check_source
     if: fromJSON(needs.check_source.outputs.run_tests)
     strategy:
+      fail-fast: false
       matrix:
+        os:
+          - windows-latest
         arch:
-        - Win32
-        - x64
-        - arm64
+          - x64
         free-threading:
-        - false
-        - true
+          - false
+          - true
+        include:
+          - os: windows-latest # FIXME(diegorusso): change to os: windows-aarch64
+            arch: arm64
+            free-threading: false
+          - os: windows-latest # FIXME(diegorusso): change to os: windows-aarch64
+            arch: arm64
+            free-threading: true
+          - os: windows-latest
+            arch: Win32
+            free-threading: false
     uses: ./.github/workflows/reusable-windows.yml
     with:
+      os: ${{ matrix.os }}
       arch: ${{ matrix.arch }}
       free-threading: ${{ matrix.free-threading }}
 
diff --git a/.github/workflows/reusable-ubuntu.yml b/.github/workflows/reusable-ubuntu.yml
index c6719882702ebb..c9c415600d06b8 100644
--- a/.github/workflows/reusable-ubuntu.yml
+++ b/.github/workflows/reusable-ubuntu.yml
@@ -20,7 +20,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-24.04]
+        os: [ubuntu-24.04, ubuntu-24.04-aarch64]
     env:
       FORCE_COLOR: 1
       OPENSSL_VER: 3.0.15
@@ -79,7 +79,7 @@ jobs:
         ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
     - name: Build CPython out-of-tree
       working-directory: ${{ env.CPYTHON_BUILDDIR }}
-      run: make -j4
+      run: make -j
     - name: Display build info
       working-directory: ${{ env.CPYTHON_BUILDDIR }}
       run: make pythoninfo
diff --git a/.github/workflows/reusable-windows.yml b/.github/workflows/reusable-windows.yml
index dcfc62d7f5d145..12b68d68466d62 100644
--- a/.github/workflows/reusable-windows.yml
+++ b/.github/workflows/reusable-windows.yml
@@ -3,6 +3,10 @@ name: Reusable Windows
 on:
   workflow_call:
     inputs:
+      os:
+        description: OS to run on
+        required: true
+        type: string
       arch:
         description: CPU architecture
         required: true
@@ -19,10 +23,8 @@ env:
 
 jobs:
   build:
-    name: >-
-      build${{ inputs.arch != 'arm64' && ' and test' || '' }}
-      (${{ inputs.arch }})
-    runs-on: windows-latest
+    name: 'build and test (${{ inputs.arch }})'
+    runs-on: ${{ inputs.os }}
     timeout-minutes: 60
     steps:
     - uses: actions/checkout@v4
@@ -31,17 +33,17 @@ jobs:
       run: echo "::add-matcher::.github/problem-matchers/msvc.json"
     - name: Build CPython
       run: >-
-        .\PCbuild\build.bat
+        .\\PCbuild\\build.bat
         -e -d -v
         -p ${{ inputs.arch }}
         ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
-    - name: Display build info
+    - name: Display build info  # FIXME(diegorusso): remove the `if`
       if: inputs.arch != 'arm64'
-      run: .\python.bat -m test.pythoninfo
-    - name: Tests
+      run: .\\python.bat -m test.pythoninfo
+    - name: Tests  # FIXME(diegorusso): remove the `if`
       if: inputs.arch != 'arm64'
       run: >-
-        .\PCbuild\rt.bat
+        .\\PCbuild\\rt.bat
         -p ${{ inputs.arch }}
         -d -q --fast-ci
         ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}