Error during installation or during grub menu creation #425

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1. notepass commented on Jun 5, 2026

   

   notepass

   on Jun 5, 2026

   Last edited by notepass

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   I ran into the same issue. It seems that update-grub ran into an error for me.
   This was because of 2 sources within the grub hook (/etc/grub.d/41_snapshots-btrfs in my case):

   • I am using BTRFS RAID 1, so ${grub_probe} --target=device / returned two entries, which breaks logic after it. I replaced the according line (around line 124 or so) with root_device="$(${grub_probe} --target=device /|head -n 1)" # e.g. /dev/mapper/enc
   • The awk call after the comment #Root subvolume UUID did not work for me. So I replaced it with a grep chain (I can't read awk, so I don't know where the error there is). My line looks like this: root_uuid_subvolume="$(btrfs subvolume show / 2>/dev/null | grep -E '^\s+UUID:'|grep -Eo '[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}')"

   This gets me to the point where I can get to the point where I see "grub-btrfs: No snapshots found.", as I have no snapshots yet. So I will continue to see if everything else works as soon as I have snapshots.

   Having a look at the PRs, at least the awk problem seems to be solved in #433 . The other issue might also have a PR, I would need to check that at some point.

   Hope this can help you as well.

   EDIT: #413 seems to solve the RAID issue as well

   🎉React with 🎉1Reacted by Samuel
2. quizilkend commented on Jun 8, 2026

   

   quizilkend

   on Jun 8, 2026

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   @notepass thank you for your investigation and writeup! I will definitely have a look into it.
3. Antynea

   added a commit that references this issue on Aug 24, 2026

   fix: empty fs_uuid on multi-device Btrfs (#440)

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   d344496
4. Antynea

   closed this as completedin d83c4beon Aug 24, 2026
5. Antynea commented on Aug 24, 2026

   

   Antynea

   on Aug 24, 2026

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   This thread had two separate causes stacked on top of each other, and both are now fixed on master.

   The first was multi-device Btrfs: grub-probe --target=device prints one line per device, and the whole multi-line value was being passed on to the UUID probe, which then returned nothing. Fixed in #440.

   The second was the awk parsing: the script used \s, a GNU extension that mawk treats as a literal s, so the expression never matched the tab-indented UUID line. Since awk is mawk by default on Debian and derivatives, this only showed up there. Fixed in #441.

   Closing this one. If anything is still off on current master, reopen and I'll take another look. Thanks for the patience, this sat here far longer than it should have.
6. gh-actions-shared

   added a commit that references this issue on Aug 24, 2026

   fix: use portable whitespace matching in awk UUID parsing (Antynea#441)

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   This issue will close once commit d83c4be is merged into the 'master' branch.

   d83c4be