diff --git a/.github/workflows/custom-board-build/action.yaml b/.github/workflows/custom-board-build/action.yaml
index 5815d064bb..a6cedebd70 100644
--- a/.github/workflows/custom-board-build/action.yaml
+++ b/.github/workflows/custom-board-build/action.yaml
@@ -77,6 +77,11 @@ inputs:
 runs:
   using: "composite"
   steps:
+    - name: Check branch name
+      shell: bash
+      if: ${{ contains(github.ref_name, '.') }}
+      run: echo '::error::Branch names must not contain ".", this breaks firmware autoupdates.' && exit 1
+
     - name: Mask Secrets
       shell: bash
       run: |