Some time ago I installed Ubuntu 20.04 following this guide with btrfs-luks encryption.

The boot process used to involve only a single passphrase prompt at the very beginning.

Today, after upgrading to Ubuntu 22.04, booting fails.

I still receive a passphrase prompt at the very beginning of the boot process. But now I am receiving the following output (all UUIDs modified for clarity):

Btrfs loaded, crc32c=crc32c-intel, zoned=yes, fsverity=yes

Scanning for Btrfs filesystems

done.

Begin: Waiting for root file system ... Begin Running /scripts/local-block ... done.

done.

Gave up waiting for root file system device. Common problems:

- Boot args (cat /proc/cmdline)

  - Check rootdelay= (did the system wait long enough?)

- Midding modules (cat /proc/modules; ls /dev)

ALERT! UUID=xxx-xxx-xxx-xxx-xxx does not exist. Dropping to a shell!

After this output, it drops me into a (initramfs) prompt.

Running cat /proc/cmdline gives me:

BOOT_IMAGE=/@/boot/vmlinuz-5.15.0-46-generic root=UUID=xxx-xxx-xxx-xxx-xxx ro rootflags=subvol=@

Listing disks by uuid via ls -l /dev/disk/by-uuid/ gives me (again, UUIDs are replaced for clarity):

aaa-aaa-aaa-aaa-aaa -> ../../nvem0n1p2

bbb-bbb-bbb-bbb-bbb -> ../../nvem0n1p3

ccc-ccc -> ../../nvme0n1p1

ddd-ddd-ddd-ddd-ddd -> ../../nvme0n1p4

So, the UUID mentioned is not available.

If I decrypt manually using cryptsetup open /dev/nvme0n1p3 cryptdata (and entering the passphrase again) I receive:

BTRFS: device fsid=xxx-xxx-xxx-xxx-xxx devid 1 transid 797369 /dev/dm-0 scanned by systemd-udevd (527)

When I now run ls -l /dev/disk/by-uuid/, the missing uuid is now included:

aaa-aaa-aaa-aaa-aaa -> ../../nvem0n1p2

bbb-bbb-bbb-bbb-bbb -> ../../nvem0n1p3

ccc-ccc -> ../../nvme0n1p1

ddd-ddd-ddd-ddd-ddd -> ../../nvme0n1p4

xxx-xxx-xxx-xxx-xxx -> ../../dm-0

When I now exit, the boot process continues running without problem.

Now I am looking for a way to have the boot process run by itself again. I suspect that some config file might have been overwritten during the upgrade, and I think in addition to the installation guide linked above some adjustments have been necessary, but I do not remember exactly.

What I have tried:

• Booting from a USB stick, decrypting and mounting manually, chroot into the mount, and running update-initramfs as suggested by answers to similar questions. No effect.