diff --git a/.github/workflows/build-ros.yml b/.github/workflows/build-ros.yml
index 4ec0f30a..1232921f 100644
--- a/.github/workflows/build-ros.yml
+++ b/.github/workflows/build-ros.yml
@@ -1,7 +1,7 @@
 # Based on GTSAM file (by @ProfFan)
 name: CI Build colcon
 
-on: [push, pull_request]
+on: [push]
 
 jobs:
   build_docker: # On Linux, iterates on all ROS 1 and ROS 2 distributions.
@@ -50,8 +50,14 @@ jobs:
       image: ${{ matrix.docker_image }}
 
     steps:
-      - name: Checkout source code
-        uses: actions/checkout@v3
+      - name: Checkout
+        run: |
+          apt-get -y update
+          apt-get -y install git
+          git clone https://github.com/$GITHUB_REPOSITORY.git --recursive "$GITHUB_WORKSPACE"
+          git config --global --add safe.directory "$GITHUB_WORKSPACE"
+          git checkout $GITHUB_SHA
+          git submodule update --init --recursive
 
       - name: setup ROS environment
         uses: ros-tooling/setup-ros@v0.7