grub.cfg for RAID devices

[Stéphane Delaunay]

Hello everyone,

I'm currently trying to set up my Thinkpad T430 with coreboot and GRUB on flash 
and have hit a wall with the grub.cfg.

My planned drive setup is a bit unconventional, but rather simple:

Two physical SSDs, SATA & mSATA: (ahci0) & (ahci2)
Four partitions, two on each drive: (ahci0,msdos1), (ahci0,msdos2) & 
(ahci2,msdos1), (ahci2,msdos2)
Two RAID1 disks from these partitions, via mdadm: (md/0) & (md/1)

md0 would be the boot partition and md1 as a LUKS2 root partition.

The idea is to have a laptop on which one drive could fail and the other one 
would still be bootable.

The problem is that I haven't been able to boot my system, yet. I'm currently 
using this grub.cfg on flash: 
https://notabug.org/libreboot/lbmk/src/master/resources/grub/config/grub.cfg

It can see all drive partitions, but does not find the RAID devices. Even if I 
manually enter "insmod mdraid1x" and go back to "normal", I can't automatically 
boot with the default function. It is also unable to read the boot partitions 
by themselves for an "error: unknown filesystem." Currently installed is a 
Debian 11 system.

If I try to manually boot via "linux (md/0)/vmlinuz..." and "initrd 
(md/0)/initrd.img...", I can load the kernel and unlock my root drive, but 
couldn't start the system yet and land in a BusyBox (although, I assume this is 
because I may have made an error with the "root=" directory).

Overall, I need some help to point me in the right direction to be able to 
start my system automatically on boot. Preferably one that is able to handle my 
use case when one drive should fail.

Any hints are appreciated. :)

Kind regards!