diff --git a/src/backend/bs_signer b/src/backend/bs_signer
index fc86e74e0b8..01f3fadb343 100755
--- a/src/backend/bs_signer
+++ b/src/backend/bs_signer
@@ -463,7 +463,7 @@ sub signjob {
 	if ($signfile =~ /\.AppImage$/ && -e "$jobdir/$signfile.zsync") {
 	  print("regenerating zsync file\n");
 	  # re-generate zsync data
-	  if (system('zsyncmake', '-o', "$jobdir/$signfile.zsync.new", "$jobdir/$signfile")) {
+	  if (system('zsyncmake', '-u', $signfile, '-o', "$jobdir/$signfile.zsync.new", "$jobdir/$signfile")) {
 	    print("zync file recreation failed: $?\n");
 	    unlink("$jobdir/$signfile.zsync.new");
 	  } else {