diff --git a/pkgs/clerie-update-nixfiles/clerie-merge-nixfiles-update.sh b/pkgs/clerie-update-nixfiles/clerie-merge-nixfiles-update.sh
index 7f402d3..8626340 100755
--- a/pkgs/clerie-update-nixfiles/clerie-merge-nixfiles-update.sh
+++ b/pkgs/clerie-update-nixfiles/clerie-merge-nixfiles-update.sh
@@ -45,7 +45,13 @@ echo "[!] Checkout master"
 xgit checkout master
 
 echo "[!] Update master"
-xgit pull origin master
+set +e
+if ! xgit merge --ff-only origin/master; then
+	echo "[!] Merging failed"
+	echo "[!] Please clean up master branch and try again"
+	exit 1
+fi
+set -e
 
 echo "[!] Fetch git commit of last hydra run"
 echo "[!] Checking https://hydra.clerie.de/jobset/nixfiles/nixfiles-updated-inputs/latest-eval"