diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 87f411b..cc66ccf 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -35,8 +35,7 @@ jobs:
         run: |
           cd ./firmware/build
           rm -rf -- ..?* .[!.]* *
-          export CFLAGS="-D_BASE_VIDEO_MODE=1"
-          cmake .. -G Ninja -DPICO_SDK_PATH=../../pico-sdk
+          cmake .. -G Ninja -DBASE_VIDEO_MODE=1 -DPICO_SDK_PATH=../../pico-sdk
           ninja
       - name: 'Upload base video mode artifacts'
         uses: actions/upload-artifact@v4