I did a kernel upgrade on my desktop system from 2.6.32-41 to 2.6.32-42 using apt-get dist-upgrade. I opted not to update /boot/grub/menu.lst and added the required lines myself, based on the previous version. (As I found from previous experience that the automatic update trashes the existing entires!) So the relevant lines for non-recovery mode read:
title Ubuntu 10.04.4 LTS, kernel 2.6.32-42-generic uuid 099b8ec7-c3b2-4f46-a52c-8e95d6a7b9de kernel /vmlinuz-2.6.32-42-generic root=/dev/smallvg-filesystemlv ro quiet splash initrd /initrd.img-2.6.32-42-generic quiet title Ubuntu 10.04.4 LTS, kernel 2.6.32-41-generic uuid 099b8ec7-c3b2-4f46-a52c-8e95d6a7b9de kernel /vmlinuz-2.6.32-41-generic root=/dev/mapper/smallvg-filesystemlv ro quiet splash initrd /initrd.img-2.6.32-41-generic quiet
2.6.32-41 boots normally; 2.6.32-42 fails because it can't find the root partition, as the logical volume isn't mounted. It drops me into busybox, from which (as suggested in answers to previous similar problems) I can use
lvm vgchange -ay
to verify that lvm is present and the partitions are visible to it.
I have examined and compared the 2 /boot/initrd.img* files, and as far as I can tell the contained files and their contents are the same (apart from the version changes), and checked the 2 /boot/config* files, which again only differ by version numbers.
This seems to be a similar problem to this one, which doesn't yet appear to have been resolved, although baronKarza doesn't specify the kernel numbers involved.
So I am at a loss to work out where it is broken. Has anyone else experienced this? Can anyone help, please?