[ABORTED] Gentoo not detected by Debian's GRUB

kgdrenefort · Last edited by kgdrenefort on Fri Oct 06, 2023 10:16 am; edited 1 time in total

Hello,

This topic is out-dated, an installation with LVM seems to brings too many problems as it is for now. I re-installed the system, and I have still problem to boot it up, more here.

Thanks for your time and help, will try to close this topic.

this is the context:

I use SystemD Stage and follow the AMD64 Handbook.

From Debian 12 I resized my hard drive and set up a volume group (LVM) of 250Gb to host a Gentoo fresh installation. Both hard drive containing OS are using GPT tables. Alongside them there is also a Windows 11. I used a chroot to install Gentoo from Debian.

In that volume group I have:

/ : 64Gb, ext4
/home: 128Gb, ext4
/usr/src: 10Gb, ext4
/var/cache/distfiles: 30Gb, ext4
/var/tmp/portage: tmpfs

In fstab these partition are mounted like this:

pc_user4 · n00b Joined: 14 Sep 2023 Posts: 15

Hello kgdrenefort,

I could be wrong, but from inspecting your setup, it seems that Debian installed the bootloader to the ESP created by Windows, but in your actual Debian install, the /boot and /boot/efi appear to be within the context of your / partition.

If you run df after boot, see if your ESP partition is showing up in the list. This is an easy way to see if it had been loaded by the OS.

Potentially, you need to make sure to unmount the ESP after booting into both Debian and Gentoo separately, where you can then find if there are files within /boot or /boot/efi which are actually on the / partition, then remove the contents of those directories if this is the case. Then you would mount the real ESP (which contains the folders 'debian' and 'Microsoft') and re-run the grub-install. Hopefully, after doing this on both Linux installs, you have a Grub menu for Gentoo, Debian and Windows.

If you use systemd, I would recommend systemd-boot over grub, there is much less that can go wrong - if you are on OpenRC this is obviously not an option. I feel that maybe systemd-boot adoption is sparse in the Gentoo community so if a guide would be helpful, I could write one.

edit:
I've seen that you have two boot partitions

kgdrenefort · Posted: Tue Sep 19, 2023 9:51 am Post subject:

sMueggli · Guru Joined: 03 Sep 2022 Posts: 500

Please boot Debian and show the entire /boot/grub/grub.cfg and /etc/default/grub.

NeddySeagoon · Posted: Tue Sep 19, 2023 10:12 am Post subject:

pc_user4,

The bios_boot partition is used by grub when BIOS booting and GPT are in use.
That's a combination that is not supported everywhere. That's the only time its required.

A 2M bios_boot is adequate, if its needed at all. Grub uses it raw. It does not have a filesystem and it does not belong to the user.

With BIOS booting, the first stage of the boot loader is the the MBR, in LBA 0. The next part follows, in the free space before the first partition when BIOS is in use.
When GPT is in use, the GPT starts at LBA 1, so that space is not available. Grub uses the bios_boot partition instead.

With EFI booting, the firmware loads an EFI compliant program from the ESP. There is no part of the boot loader outside of any filesystem.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

kgdrenefort · Posted: Tue Sep 19, 2023 10:15 am Post subject:

sMueggli · Guru Joined: 03 Sep 2022 Posts: 500

Please make sure you have installed the package "lvm2" on Debian.

Then mount the partition which contains the /boot directory of Gentoo and rerun "sudo update-grub" and also "sudo os-prober". Share the input and output of the executed commands.

EDIT: And please show also from Debian: