diff --git a/modules/installer/grub/grub.nix b/modules/installer/grub/grub.nix
index 97e5f12d048..94522c3c059 100644
--- a/modules/installer/grub/grub.nix
+++ b/modules/installer/grub/grub.nix
@@ -206,7 +206,6 @@ in
     # Common attribute for boot loaders so only one of them can be
     # set at once.
     system.boot.loader.id = "grub";
-    system.boot.loader.kernelFile = pkgs.stdenv.platform.kernelTarget;
 
     environment.systemPackages = mkIf config.boot.loader.grub.enable [ grub ];
 
diff --git a/modules/system/activation/top-level.nix b/modules/system/activation/top-level.nix
index dedfb9a9bd8..3edc92d502c 100644
--- a/modules/system/activation/top-level.nix
+++ b/modules/system/activation/top-level.nix
@@ -36,7 +36,7 @@ let
     };
 
     system.boot.loader.kernelFile = mkOption {
-      default = "";
+      default = pkgs.stdenv.platform.kernelTarget;
       description = ''
         Name of the kernel file to be passed to the bootloader.
       '';
@@ -152,7 +152,7 @@ let
     inherit children;
     kernelParams =
       config.boot.kernelParams ++ config.boot.extraKernelParams;
-    menuBuilder = config.system.build.menuBuilder;
+    menuBuilder = config.system.build.menuBuilder or "true";
     initScriptBuilder = config.system.build.initScriptBuilder;
     activationScript = config.system.activationScripts.script;
     nixosVersion = config.system.nixosVersion;