Re: grub

[didier gaumet <didier.gaumet@gmail.com>]

Le 29/10/2025 à 23:58, Gerard ROBIN a écrit :
> Hello,

Hello

> Here is the result of the command: dpkg -l grub (with Trixie)
>
> ii  grub-common                 2.12-9       amd64      GRand Unified Bootloader (common files)
> ii  grub-efi-amd64              2.12-9       amd64      GRand Unified Bootloader, version 2 (EFI-AMD64 version)
> ii  grub-efi-amd64-bin          2.12-9       amd64      GRand Unified Bootloader, version 2 (EFI-AMD64 modules)
> ii  grub-efi-amd64-signed       1+2.12+9     amd64      GRand Unified Bootloader, version 2 (amd64 UEFI signed by Debian)
> ii  grub-efi-amd64-unsigned     2.12-9       amd64      GRand Unified Bootloader, version 2 (EFI-AMD64 images)
> ii  grub2-common                2.12-9       amd64      GRand Unified Bootloader (common files for version 2)
>
> Some packages are redundant;

No :-)

> what is their purpose?
> If some are useless, can they be removed?
> For example, what is the use of having:
>
> grub-efi-amd64,
> grub-efi-amd64-signed,
> grub-efi-amd64-unsigned
>
> Which one is actually used at startup?
>
> Thanks.

didier@hp-notebook14:~$ apt show grub-efi-amd64
Package: grub-efi-amd64
[...]
Installed-Size: 190 kB
[...]
This is a dependency package for a version of GRUB that has been built for
use with the EFI-AMD64 architecture, as used by Intel Macs (unless a BIOS
interface has been activated).  Installing this package indicates that this
version of GRUB should be the active boot loader.

didier@hp-notebook14:~$ apt show grub-efi-amd64-signed
[...]
Installed-Size: 9720 kB
[...]This package contains the binaries signed by the Debian UEFI CA to 
be used by
shim-signed.

didier@hp-notebook14:~$ apt show grub-efi-amd64-unsigned
[...]
Installed-Size: 9715 kB
[...]
This package contains GRUB images that have been built for use with the
EFI-AMD64 architecture, as used by Intel Macs (unless a BIOS interface has
been activated).  It can be installed in parallel with other flavours, but
will not automatically install GRUB as the active boot loader nor
automatically update grub.cfg on upgrade unless grub-efi-amd64 is also
installed.

Globally on an amd64 platform with an UEFI firmware, grub-efi-amd64-bin 
depends on grub-efi-amd64-unsigned and recommends grub-efi-amd64-signed.
I could be wrong but my understanding is that all the packages you 
mention are useful and you cannot remove them without breaking grub. The 
one exception being grub-efi-amd64-signed that you can remove if:
- you don't mind not satisfying recommends for the package system
- you don't use Secure Boot ('-signed: Secure Boot, '-unsigned: no 
Secure Boot). You can then also remove all shim-* packages