diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6f8c12ad..77cc291b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -40,6 +40,7 @@ jobs:
         with:
           repository: 'YosysHQ/yosys'
           path: 'yosys'
+          submodules: true
 
       - name: Runtime environment
         run: |