diff --git a/pkgs/by-name/firefox-extensions/package.nix b/pkgs/by-name/firefox-extensions/package.nix
index f767c0f5c..df20eb095 100644
--- a/pkgs/by-name/firefox-extensions/package.nix
+++ b/pkgs/by-name/firefox-extensions/package.nix
@@ -28,7 +28,7 @@ let
     extid = addon.passthru.extid;
     # merge our requirements into the derivation args
     args' = args // {
-      passthru = addon.passthru // (args.passthru or {});
+      passthru = (builtins.removeAttrs addon.passthru ["updateScript"]) // (args.passthru or {});
       nativeBuildInputs = [
         jq
         strip-nondeterminism