Re: Permanently fix absolute location of the GRUB folder

[Pascal Hambourg]

Le 13/11/2017 à 09:10, Luí­s Moreira de Sousa a écrit :
> I recently hit a relatively common problem whit the Ubuntu 16.04 installer, 
> that misconfigures the location of the GRUB folder [0]. In such cases the 
> system boots into a rescue shell with the following messages:
>
> error: file '/grub/i386-pc/normal.mod' not found.

Matches :

>  => Grub2 (v2.00) is installed in the MBR of /dev/sda and looks at sector 1 of 
>     the same hard drive for core.img. core.img is at this location and looks 
>     for (,msdos1)/grub.

the missing "/boot" in the path means that this GRUB was installed with 
/boot on a separate partition.

> This means GRUB was able to boot, but it is looking for its modules in the 
> wrong place. The well known solution is to instruct GRUB on the fly on the 
> location of its modules [1]. In my case this is:
>
> grub rescue> set prefix=(hd1,msdos2)/boot/grub

meaning that another GRUB was installed on another drive (hd0 is always 
the boot drive in BIOS boot) with /boot in the root partition. Matches :

> => Grub2 (v2.00) is installed in the MBR of /dev/sdg and looks at sector 1 of 
>     the same hard drive for core.img. core.img is at this location and looks 
>     for (,msdos2)/boot/grub.

My guess is that the system is booting GRUB in BIOS/legacy mode from 
sda, which contains a remain of GRUB from a previous installation, not 
from sdg. Fortunately for you, the two GRUBs are compatible enough.

Also, it seems that /dev/sdg contains both EFI and BIOS/legacy GRUBs.