diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e815870..18f3e23 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -222,6 +222,7 @@ jobs:
         uses: actions/checkout@v2
         with:
           repository: status-im/nimbus-eth2
+          ref: unstable
           path: nbc
           submodules: true
           fetch-depth: 0