diff --git a/nixos/hosts/nixos-rpi4-img/default.nix b/nixos/hosts/nixos-rpi4-img/default.nix
index f8691b80..ead31d5b 100644
--- a/nixos/hosts/nixos-rpi4-img/default.nix
+++ b/nixos/hosts/nixos-rpi4-img/default.nix
@@ -1,7 +1,7 @@
 { config, lib, pkgs, modulesPath, platform, ... }: {
   # Build this image with:
   # nix build .#nixosConfigurations.nixos-rpi4-img.config.system.build.sdImage
-  nixpkgs.hostPlatform.system = lib.mkDefault "aarch64-linux";
+  nixpkgs.hostPlatform.system = "aarch64-linux";
   nixpkgs.buildPlatform.system = "x86_64-linux";
   networking.hostName = "nixos-rpi4-img";
   networking.firewall.allowedTCPPorts = [ 22 ];