diff --git a/.github/workflows/build-linux.yml b/.github/workflows/build-linux.yml
index 633be2ba4c3..57e690c777e 100644
--- a/.github/workflows/build-linux.yml
+++ b/.github/workflows/build-linux.yml
@@ -25,6 +25,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/chart-tests.yml b/.github/workflows/chart-tests.yml
index 3025434307a..1cedaa0e7cc 100644
--- a/.github/workflows/chart-tests.yml
+++ b/.github/workflows/chart-tests.yml
@@ -20,6 +20,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/feature-tests.yml b/.github/workflows/feature-tests.yml
index 03147773b13..a9ddb1e14a1 100644
--- a/.github/workflows/feature-tests.yml
+++ b/.github/workflows/feature-tests.yml
@@ -22,6 +22,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/fingerprint-tests.yml b/.github/workflows/fingerprint-tests.yml
index 1e0f307ee80..70614f0e6c2 100644
--- a/.github/workflows/fingerprint-tests.yml
+++ b/.github/workflows/fingerprint-tests.yml
@@ -23,6 +23,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/module-tests.yml b/.github/workflows/module-tests.yml
index 3b3b33eca88..10c783489d4 100644
--- a/.github/workflows/module-tests.yml
+++ b/.github/workflows/module-tests.yml
@@ -21,6 +21,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/other-tests.yml b/.github/workflows/other-tests.yml
index ce2be237d46..d6007ae2ea9 100644
--- a/.github/workflows/other-tests.yml
+++ b/.github/workflows/other-tests.yml
@@ -22,6 +22,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/statistical-tests.yml b/.github/workflows/statistical-tests.yml
index 75299f0e283..ca91908ac59 100644
--- a/.github/workflows/statistical-tests.yml
+++ b/.github/workflows/statistical-tests.yml
@@ -20,6 +20,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/unit-tests.yml b/.github/workflows/unit-tests.yml
index 7ddfbada665..135c5baa2ab 100644
--- a/.github/workflows/unit-tests.yml
+++ b/.github/workflows/unit-tests.yml
@@ -21,6 +21,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet
diff --git a/.github/workflows/validation-tests.yml b/.github/workflows/validation-tests.yml
index 018dd0f6a8e..bdc0640348e 100644
--- a/.github/workflows/validation-tests.yml
+++ b/.github/workflows/validation-tests.yml
@@ -20,6 +20,7 @@ jobs:
         with:
           repository: omnetpp/omnetpp
           path: omnetpp
+          ref: omnetpp-6.x
       - uses: actions/checkout@v4
         with:
           path: inet