bug#53459: Update: Tried non efi, independent boot partition and custom boot entry in debian

[Néstor Arocha]

Hi,

I forgot to mention that I am working with current stable guix 1.3.0

I also tried a few things:
 * Manual installation doesn't trigger the error at all, but the end result is 
that it won't boot like before
 * an independent boot partition on top of a shared /boot/efi didn't make any 
difference
 * Trying to install guix with the boot-grub loader rather than efi didn't work 
at all and the boot installed errored

But I am happy to say that (after standard guix install) adding the entry in 
grub manually in debian
did work:

```
menuentry "Guix" {
   insmod part_gpt
   insmod chain
   set root='(hd0,gpt1)'
   chainloader /EFI/Guix/grubx64.efi
}
```

and then running update-grub

For some reason it asks for the encryption password twice.