initramfs shell after upgrade to Ubuntu 22.04 - raid

Question

I upgraded from 20.04 to 22.04 and after reboot I get the following screen / errors (see screenshot) and it goes to the initramfs shell. It's a RAID system. It might be that boot partition was too full during upgrade, or that when freeing space pre-upgrade I deleted too much (and wrongly) from the boot folder. In the Grub menu there's two kernels to choose from (generic and low-latency variant) but none of them work, all revert to initramfs shell.

Problem sounds similar to: System boots to initramfs after upgrade from 21.10 to 22.04 "dmsetup ls" shows indeed the block devices (see screenshot) but partprobe is not found. EDIT: I managed to mount the partitions when booting into a Live USB. But still don't know how to make the system boot.

Can someone provide advice please? I'm pretty lost here... what other information do I have to provide to debug this properly?

Thanks in advance

Answer 1

Bug report with patch: https://bugs.launchpad.net/ubuntu/+source/dmraid/+bug/2047303

initramfs needs to be regenerated after patch is applied (What does "regenerate your initramfs" mean?)

• OS can be booted from the above point (initramfs shell) by manually detecting the partitions like via 'kpartx' (Boot fails after upgrading from 20.04 to 22.04 on dmraid device, no partitons).
• If boot partition is encrypted, it must manually be unlocked before continuing
  • cryptsetup open /dev/mapper/name-of-os-volume expected-name-of-unlocked-volume
  • Encrypted disk not available in boot process after distro upgrade
• type 'exit' to continue booting. Boot will succeed if nothing else is wrong and the encrypted volume was opened with the name the OS expects

Lots of posts over many years indicate that dmraid is awful/obsolete and should be replaced with mdadm without question. Take great care in attempting to retrofit an existing installation. The two technologies use completely different naming schemes for devices and the references will need to be updated. I've not yet come across end-to-end instructions that work and I've spent many hours re-learning how to recover my boot partition after mdadm was unexpectedly installed.