diff --git a/nixos/modules/system/activation/activatable-system.nix b/nixos/modules/system/activation/activatable-system.nix
index c3739f627a16..6513706b2769 100644
--- a/nixos/modules/system/activation/activatable-system.nix
+++ b/nixos/modules/system/activation/activatable-system.nix
@@ -74,7 +74,7 @@ in
         ''
           cp ${activationScript} $out/activate
           cp ${dryActivationScript} $out/dry-activate
-          ${lib.getExe pkgs.gnused} --in-place --expression "s|@out@|''${!toplevelVar}|g" $out/activate $out/dry-activate
+          ${lib.getExe pkgs.buildPackages.gnused} --in-place --expression "s|@out@|''${!toplevelVar}|g" $out/activate $out/dry-activate
         '';
 
       system.systemBuilderCommands = lib.mkIf config.system.activatable config.system.activatableSystemBuilderCommands;