Re: Do I need to act on this warning from apt when installing grub?

[Pascal]

          INTEL/MBR           GPT
         PARTITIONING     PARTITIONING
      +----------------+----------------+
      |MBR             |MBR             |
      |POST-MBR-GAP    |GPT             |
      |+--------------+|+--------------+|
      ||PART          |||PART BIOS-BOOT||
      ||/boot/grub/   ||+--------------+|
 BIOS ||...           ||+--------------+|
 BOOT ||              |||PART ESP (FAT)||
      ||              |||/boot/grub/   ||
      ||              |||...           ||
      |+--------------+|+--------------+|
      +----------------+----------------+
      |                |                |
      |                |GPT             |
      |+--------------+|+--------------+|
      ||PART ESP (FAT)|||PART ESP (FAT)||
      ||/boot/grub/   |||/boot/grub/   ||
 UEFI ||...           |||...           ||
 BOOT ||              |||              ||
      ||              |||              ||
      ||              |||              ||
      |+--------------+|+--------------+|
      +----------------+----------------+

Le mer. 14 déc. 2022 à 12:36, Goh Lip <g.lip@gmx.com> a écrit :

>
>
> On 12/14/22 17:15, Chris Green wrote:
> > On Wed, Dec 14, 2022 at 10:31:40AM +0800, Goh Lip wrote:
> >>
> >>
> >> On 13/12/2022 18:55, Chris Green wrote:
>
> >>
> >> Is your partition table GPT, not msdos?
> >>
> > Yes, it's GPT:-
> >
> >      Disk /dev/sda: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
>
> >      Disklabel type: gpt
>
> >
> >      Device       Start        End    Sectors  Size Type
> >      /dev/sda1     2048       4095       2048    1M BIOS boot
> >      /dev/sda2     4096    1054719    1050624  513M EFI System
> >      /dev/sda3  1054720 1953523711 1952468992  931G Linux filesystem
> >
> >
> > (There's an 8Tb USB drive as well, this is my backup system which
> > lives in the garage, quite a way away from the house)
> >
>
>
> See
> https://www.gnu.org/software/grub/manual/grub/grub.html#BIOS-installation
>
> To set up bios-legacy boot on gpt partitioning properly, you will need a
> small partition labelled "bios_grub".
> And yes, without it, as you found out, it will still install and boot.
> But it will not be reliable and will, in time, likely to fail again. And
> you can still make it work again the way you have done (and will likely
> fail again).
>
> Personally, I would suggest that for gpt partitioning, boot in uefi. And
> in msdos partitioning, boot in bios-legacy (though that too can be
> booted in uefi boot - with unreliable performance).
>
> Hope this explains. Regards.
>
> ps: best when issuing grub-install command, use "--target=i386-pc" in
> that command for boot-legacy boots and "--target=x86_64-efi" for uefi
> boots, especially when installing legacy in gpt or uefi in msdos (latter
> always not recommended, but I've done it)
>
>
>
>