Comment 4 for bug 576071

I ran into this out of the blue running 9.10 on a laptop with SATA hard drive, one primary ext3 and one swap parition, and no previous boot problems.
Boot failed, dropping to busybox shell showing no by-uuid entry for the primary partition (the swap partition was there). Possibly - I'm not certain - this was on first reboot after a system update.
Eventually rebooted successfully by giving root=/dev/sda4 on the grub command line. After that the problem vanished without my changing any configuration files (I still have root=UUID=xxxx in /boot/grub/menu.lst).
Perhaps there is more to this than the diagnosis suggested in the initial bug report, which doesn't seem to account for the problem resolving after reboot.