diff --git a/.github/workflows/m5atom-matrix.yml b/.github/workflows/m5atom-matrix.yml
index c52240d..e4e294d 100644
--- a/.github/workflows/m5atom-matrix.yml
+++ b/.github/workflows/m5atom-matrix.yml
@@ -27,6 +27,8 @@ jobs:
         key: ${{ runner.os }}-${{ hashFiles('**/lockfiles') }}
     - name: Set up Python
       uses: actions/setup-python@v2
+      with:
+          python-version: 3.8
     - name: Install PlatformIO
       run: |
         python -m pip install --upgrade pip