Title: GRUB upgrades
Author: Mike Gilbert <floppym@gentoo.org>
Posted: 2024-02-01
Revision: 2
News-Item-Format: 2.0
Display-If-Installed: sys-boot/grub
When booting with GRUB, it is important that the core image and modules
have matching versions. Usually, running grub-install is sufficient to
ensure this.
On the UEFI platform, grub-install allows the core image to be placed in
two different locations:
EFI/gentoo/grubx64.efi
This is the location used by grub-install without options.
EFI/BOOT/BOOTX64.EFI
This is the location used by grub-install --removable.
On upgrades, it is common for users to mismatch the grub-install options
they used for the current and previous versions of grub. This will cause
a stale core image to exist. For example:
/boot/efi/EFI/BOOT/BOOTX64.EFI (grub 2.06 core image)
/boot/efi/EFI/gentoo/grubx64.efi (grub 2.12 core image)
/boot/grub/x86_64-efi/*.mod (grub 2.12 modules)
Booting this system using BOOTX64.EFI image would likely fail due to a
symbol mismatch between the core image and modules. [1]
Re-runing grub-install both with and without the --removable option
should ensure a working GRUB installation.
However, this will clobber any BOOTX64.EFI image provided by other
loaders. If dual-booting using another boot loader, users must take care
not to replace BOOTX64.EFI if it is not provided by GRUB.
References:
[1] https://bugs.gentoo.org/920708
