EFISTUB using UEFI directly with efibootmgr

[Yuu Yin]

Hello,

Is it possible to set EFISTUB using UEFI directly with efibootmgr[1]? What to 
set for `--loader` (the vmlinux/vmlinuz)? and `initrd=`?

```sh
efibootmgr --help | grep loader
-l | --loader name     (defaults to "\EFI\gnu\grub.efi")
```

But I do not want to interop GRUB with efibootmgr.

- [1] https://wiki.archlinux.org/title/EFISTUB#efibootmgr

Yuu Yin