diff --git a/nixos/modules/system/boot/uki.nix b/nixos/modules/system/boot/uki.nix
index 63c4e0c0e391..63a7cbc5967b 100644
--- a/nixos/modules/system/boot/uki.nix
+++ b/nixos/modules/system/boot/uki.nix
@@ -51,16 +51,16 @@ in
     else
       "nixos");
 
-    boot.uki.settings = lib.mkOptionDefault {
+    boot.uki.settings = {
       UKI = {
-        Linux = "${config.boot.kernelPackages.kernel}/${config.system.boot.loader.kernelFile}";
-        Initrd = "${config.system.build.initialRamdisk}/${config.system.boot.loader.initrdFile}";
-        Cmdline = "init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}";
-        Stub = "${pkgs.systemd}/lib/systemd/boot/efi/linux${efiArch}.efi.stub";
-        Uname = "${config.boot.kernelPackages.kernel.modDirVersion}";
-        OSRelease = "@${config.system.build.etc}/etc/os-release";
+        Linux = lib.mkOptionDefault "${config.boot.kernelPackages.kernel}/${config.system.boot.loader.kernelFile}";
+        Initrd = lib.mkOptionDefault "${config.system.build.initialRamdisk}/${config.system.boot.loader.initrdFile}";
+        Cmdline = lib.mkOptionDefault "init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}";
+        Stub = lib.mkOptionDefault "${pkgs.systemd}/lib/systemd/boot/efi/linux${efiArch}.efi.stub";
+        Uname = lib.mkOptionDefault "${config.boot.kernelPackages.kernel.modDirVersion}";
+        OSRelease = lib.mkOptionDefault "@${config.system.build.etc}/etc/os-release";
         # This is needed for cross compiling.
-        EFIArch = efiArch;
+        EFIArch = lib.mkOptionDefault efiArch;
       };
     };