diff --git a/overlays/nixpak/firefox.nix b/overlays/nixpak/firefox.nix
index 40fc99f..87b32f3 100644
--- a/overlays/nixpak/firefox.nix
+++ b/overlays/nixpak/firefox.nix
@@ -77,13 +77,13 @@
     wrappedFirefox = prev.wrapFirefox (sandboxed-firefox-esr.config.env // {
       meta = prev.firefox-esr.meta;
       gtk3 = prev.libcanberra-gtk3;
+      hasMozSystemDirPatch = true;
     }) {
       applicationName = "firefox-esr";
       pname = "firefox-esr";
       desktopName = "Firefox ESR";
       icon = "firefox";
       wmClass = "firefox-esr";
-      hasMozSystemDirPatch = true;
     };
   in
     wrappedFirefox;