diff --git a/.forgejo/workflows/e2e-tests.yaml b/.forgejo/workflows/e2e-tests.yaml
index 4f3a8782..8e7ef3e7 100644
--- a/.forgejo/workflows/e2e-tests.yaml
+++ b/.forgejo/workflows/e2e-tests.yaml
@@ -90,7 +90,7 @@ jobs:
       - name: Install system dependencies
         run: |
           . /etc/os-release
-          if [ "$ID" = "debian" ]; then
+          if [ "$ID" = "debian" ] && [ -f /etc/apt/sources.list ]; then
             sed -i 's/ main$/ main contrib non-free non-free-firmware/' /etc/apt/sources.list
           fi
           apt-get update
diff --git a/.forgejo/workflows/pr-tests.yaml b/.forgejo/workflows/pr-tests.yaml
index d9dfa779..937ddc25 100644
--- a/.forgejo/workflows/pr-tests.yaml
+++ b/.forgejo/workflows/pr-tests.yaml
@@ -71,7 +71,7 @@ jobs:
       - name: Install system dependencies
         run: |
           . /etc/os-release
-          if [ "$ID" = "debian" ]; then
+          if [ "$ID" = "debian" ] && [ -f /etc/apt/sources.list ]; then
             sed -i 's/ main$/ main contrib non-free non-free-firmware/' /etc/apt/sources.list
           fi
           apt-get update
diff --git a/.forgejo/workflows/production.yaml b/.forgejo/workflows/production.yaml
index 4f796574..099503af 100644
--- a/.forgejo/workflows/production.yaml
+++ b/.forgejo/workflows/production.yaml
@@ -65,7 +65,7 @@ jobs:
       - name: Install system dependencies
         run: |
           . /etc/os-release
-          if [ "$ID" = "debian" ]; then
+          if [ "$ID" = "debian" ] && [ -f /etc/apt/sources.list ]; then
             sed -i 's/ main$/ main contrib non-free non-free-firmware/' /etc/apt/sources.list
           fi
           apt-get update