diff --git a/firefox.nix b/firefox.nix
index a987bb9..cf546a7 100644
--- a/firefox.nix
+++ b/firefox.nix
@@ -7,7 +7,7 @@ let
     repo = "firefox-csshacks";
     rev = "7eca4b1050c4065130a2cf696302b4ef5d88d932";
     sparseCheckout = [ "!/*" "/chrome" "/content" ];
-    hash = lib.fakeHash;
+    hash = "sha256-rk0jC5AMw41xt5yItY7CAxuYAFhoe5Jy2tvwgh59cPI=";
   };
 in lib.mkIf hardware.graphics.enable or hardware.opengl.enable {
   programs.firefox = {