Waiting for root file system...
After doing a dist-upgrade from Etch to Lenny, I got the message "Waiting for root file system..." trying to boot the new kernel (2.6.22-3-686). Booting the previous kernel (2.6.18-5-686) works perfectly fine.
The answer to this is to (1) edit /boot/grub/menu.lst and /etc/fstab, (2) run e2label to label the ext3 file systems, (3) swapoff, mkswap, swapon to label the swap partition.
http://www.debianhelp.org/node/11653
http://linux.derkeiler.com/Mailing-Lists/Fedora/2005-07/2343.html
(4) For the DOS file system, I decided to go with UUID instead of LABEL. Since the disks already have UUID's, I can query them using "ls -l /dev/disk/by-uuid". There is more information in the following document.
http://ubuntuforums.org/showthread.php?t=168221
(5) Finally do the "update-initramfs -u -k all" as described in the first link.
Update (Feb 17, 2008). this happened again. I had to re-edit grub's menu.lst, then I re-ran update-initramfs (just to be sure).