diff --git a/flake.nix b/flake.nix
index bfba568..8380b08 100644
--- a/flake.nix
+++ b/flake.nix
@@ -313,7 +313,7 @@
             }];
           };
 
-          heimdall = inputs.nixpkgs.lib.nixosSystem {
+          heimdall = inputs.nixpkgs-u.lib.nixosSystem {
             system = "x86_64-linux";
             modules = commonModules ++ [
               inputs.nixos-hardware.nixosModules.common-cpu-amd