diff --git a/overlays/nixpak/firefox.nix b/overlays/nixpak/firefox.nix
index 7670284..f8466ce 100644
--- a/overlays/nixpak/firefox.nix
+++ b/overlays/nixpak/firefox.nix
@@ -76,5 +76,8 @@
       };
     };
   in
-    lib.makeOverridable ({name ? "firefox-esr-wrapped"}: sandboxed-firefox-esr.config.env) {};
+    prev.buildEnv {
+      name = "firefox-esr-wrapped";
+      paths = [ sandboxed-firefox-esr.config.env ];
+    };
 }