diff --git a/profiles/uvms-guest.nix b/profiles/uvms-guest.nix
index ca06e18..e8c307d 100644
--- a/profiles/uvms-guest.nix
+++ b/profiles/uvms-guest.nix
@@ -18,6 +18,7 @@ in
     uvms.zswap.enable = lib.mkEnableOption "Pass zswap.enabled=1 to kernelParams (and disable zramSwap)";
     uvms.zswap.settings = lib.mkOption {
       description = "Zswap kernel module configuration";
+      default = { };
       type = types.submodule {
         freeformType = types.attrsOf types.str;
         options.max_pool_percent = lib.mkOption {
@@ -62,9 +63,9 @@ in
     (lib.mkIf config.uvms.zswap.enable {
       zramSwap.enable = false;
       boot.kernelParams =
-        builtins.attrValues ((lib.mapAttrs (
-          name: value: "zswap.${name}=${toString value}"
-        )) config.uvms.zswap.settings)
+        builtins.attrValues (
+          (lib.mapAttrs (name: value: "zswap.${name}=${toString value}")) config.uvms.zswap.settings
+        )
         ++ [ "zswap.enabled=1" ];
     })
   ];