snowhawk: no more os-prober

hosts/snowhawk/hardware-configuration.nix

@@ -132,9 +132,17 @@ in
   boot.loader.grub = {
     enable = true;
     efiSupport = true;
-    useOSProber = true;
     device = "nodev";
     theme = pkgs.rose-pine-grub;
+
+    extraEntries = ''
+      menuentry 'Windows Boot Manager (on /dev/nvme0n1p1)' --class windows --class os {
+      	insmod part_gpt
+      	insmod fat
+      	search --no-floppy --fs-uuid --set=root 1A0A-CEB2
+      	chainloader /efi/Microsoft/Boot/bootmgfw.efi
+      }
+    '';
   };
   boot.loader.efi.canTouchEfiVariables = true;