diff --git a/.github/workflows/clang.yml b/.github/workflows/clang.yml
index 707a4fb..3056069 100644
--- a/.github/workflows/clang.yml
+++ b/.github/workflows/clang.yml
@@ -158,7 +158,15 @@ jobs:
       #... so we checkout manually:
       - name: checkout
         run: |
-          git clone --recursive https://github.com/biojppm/c4core .
+          set -x
+          echo $GITHUB_SERVER_URL
+          echo $GITHUB_REPOSITORY
+          echo $GITHUB_HEAD_REF
+          git init -q .
+          git remote add $GITHUB_SERVER_URL/$GITHUB_REPOSITORY
+          git fetch origin $GITHUB_HEAD_REF
+          git reset --hard FETCH_HEAD
+          git submodule update --init --recursive
       - run: git config --system --add safe.directory '*'  # needed for running in the docker image. see https://github.com/actions/checkout/issues/1169
       - run: c4core-install ${{matrix.cxx}}
       - {name: show info, run: source .github/setenv.sh && c4_show_info}
diff --git a/.github/workflows/gcc.yml b/.github/workflows/gcc.yml
index 80a25f6..55c41e4 100644
--- a/.github/workflows/gcc.yml
+++ b/.github/workflows/gcc.yml
@@ -52,7 +52,15 @@ jobs:
       #... so we checkout manually:
       - name: checkout
         run: |
-          git clone --recursive https://github.com/biojppm/c4core .
+          set -x
+          echo $GITHUB_SERVER_URL
+          echo $GITHUB_REPOSITORY
+          echo $GITHUB_HEAD_REF
+          git init -q .
+          git remote add $GITHUB_SERVER_URL/$GITHUB_REPOSITORY
+          git fetch origin $GITHUB_HEAD_REF
+          git reset --hard FETCH_HEAD
+          git submodule update --init --recursive
       - run: git config --system --add safe.directory '*'  # needed for running in the docker image. see https://github.com/actions/checkout/issues/1169
       - run: c4core-install ${{matrix.cxx}}
       - {name: show info, run: source .github/setenv.sh && c4_show_info}
@@ -99,7 +107,15 @@ jobs:
       #... so we checkout manually:
       - name: checkout
         run: |
-          git clone --recursive https://github.com/biojppm/c4core .
+          set -x
+          echo $GITHUB_SERVER_URL
+          echo $GITHUB_REPOSITORY
+          echo $GITHUB_HEAD_REF
+          git init -q .
+          git remote add $GITHUB_SERVER_URL/$GITHUB_REPOSITORY
+          git fetch origin $GITHUB_HEAD_REF
+          git reset --hard FETCH_HEAD
+          git submodule update --init --recursive
       - run: git config --system --add safe.directory '*'  # needed for running in the docker image. see https://github.com/actions/checkout/issues/1169
       - run: c4core-install ${{matrix.cxx}}
       - {name: show info, run: source .github/setenv.sh && c4_show_info}
@@ -174,7 +190,15 @@ jobs:
       #... so we checkout manually:
       - name: checkout
         run: |
-          git clone --recursive https://github.com/biojppm/c4core .
+          set -x
+          echo $GITHUB_SERVER_URL
+          echo $GITHUB_REPOSITORY
+          echo $GITHUB_HEAD_REF
+          git init -q .
+          git remote add $GITHUB_SERVER_URL/$GITHUB_REPOSITORY
+          git fetch origin $GITHUB_HEAD_REF
+          git reset --hard FETCH_HEAD
+          git submodule update --init --recursive
       - run: git config --system --add safe.directory '*'  # needed for running in the docker image. see https://github.com/actions/checkout/issues/1169
       - run: c4core-install ${{matrix.cxx}}
       - {name: show info, run: source .github/setenv.sh && c4_show_info}
@@ -277,7 +301,15 @@ jobs:
       #... so we checkout manually:
       - name: checkout
         run: |
-          git clone --recursive https://github.com/biojppm/c4core .
+          set -x
+          echo $GITHUB_SERVER_URL
+          echo $GITHUB_REPOSITORY
+          echo $GITHUB_HEAD_REF
+          git init -q .
+          git remote add $GITHUB_SERVER_URL/$GITHUB_REPOSITORY
+          git fetch origin $GITHUB_HEAD_REF
+          git reset --hard FETCH_HEAD
+          git submodule update --init --recursive
       - run: git config --system --add safe.directory '*'  # needed for running in the docker image. see https://github.com/actions/checkout/issues/1169
       - name: install gcc-arm-linux-gnueabihf
         run: |