diff --git a/maintainers/scripts/find-tarballs.nix b/maintainers/scripts/find-tarballs.nix
index 32fb5ea0111c..685a33d137ce 100644
--- a/maintainers/scripts/find-tarballs.nix
+++ b/maintainers/scripts/find-tarballs.nix
@@ -14,7 +14,7 @@ let
     operator = const [ ];
   });
 
-  urls = map (drv: { url = head (drv.urls or [ drv.url ]); hash = drv.outputHash; isPatch = (drv?postFetch); type = drv.outputHashAlgo; name = drv.name; }) fetchurlDependencies;
+  urls = map (drv: { url = head (drv.urls or [ drv.url ]); hash = drv.outputHash; isPatch = (drv?postFetch && drv.postFetch != ""); type = drv.outputHashAlgo; name = drv.name; }) fetchurlDependencies;
 
   fetchurlDependencies =
     filter