Arch Linux

joram200

Member

Registered: 2026-03-30

Posts: 2

[SOLVED] error kern fs c grub_fs_probe 122 unknown filesystem

Ever since I had reallocated an exFAT partition to my windows partition my grub doesn't function normal. When entering lsblk, the boot partition is mounted in the correct location:

NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
zram0       253:0    0   7.7G  0 disk [SWAP]
nvme0n1     259:0    0 953.9G  0 disk 
|-nvme0n1p1 259:1    0   260M  0 part 
|-nvme0n1p2 259:2    0    16M  0 part 
|-nvme0n1p3 259:3    0 751.6G  0 part 
|-nvme0n1p4 259:4    0     1G  0 part /boot
|-nvme0n1p5 259:5    0   199G  0 part /
`-nvme0n1p6 259:6    0     2G  0 part 

What should I do?

Solution:

You have to reinstall GRUB in an arch iso image on USB and make sure your system boots into the arch grub that archiso created, not GRUB itself.

Last edited by joram200 (2026-04-23 23:23:53)

frostschutz

Member

Registered: 2013-11-15

Posts: 1,647

Re: [SOLVED] error kern fs c grub_fs_probe 122 unknown filesystem

Did you reinstall Grub? (sometimes it's just a necessary module missing in grub efi or core image, or changed device name, UUID)

Can you reproduce the issue with grub-mount? Sometimes Grub stumbles over new / unusual filesystem flags, or there's a bug in Grub's filesystem driver, there was an issue like that last year but it got fixed... old thread https://bbs.archlinux.org/viewtopic.php?id=303725 (hmmm there was a bugtracker discussion too, can't find it atm)

oh, here it is https://gitlab.archlinux.org/archlinux/ … k_items/12 (maybe you can use similar steps to debug what's going on in grub, if you get to a grub shell anyways - only if the reinstall doesn't help)

Last edited by frostschutz (2026-03-30 07:24:10)

joram200

Member

Registered: 2026-03-30

Posts: 2

Re: [SOLVED] error kern fs c grub_fs_probe 122 unknown filesystem

I have fixed the issue. Seems like I had to reinstall GRUB on the arch iso image and my laptop boot into the arch grub that archiso created instead of GRUB itself.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,857

Re: [SOLVED] error kern fs c grub_fs_probe 122 unknown filesystem

\o/
Please always remember to mark resolved threads by editing your initial posts subject - so others will know that there's no task left, but maybe a solution to find.
Thanks.

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