Gave up waiting for root device. Common problems:
 - Boot args (cat /proc/cmdline)
   - Check rootdelay= (did the system wait long enough?)
   - Check root= (did the system wait for the right device?)
 - Missing modules (cat /proc/modules; ls /dev)
ALERT! /dev/disk/by-uuid/920903aa-762f-40d2-8126-87f4b0e6f975 does not exist. Dropping to a shell!

BusyBox v1.19.3 (Ubuntu 1:1.10.3-7ubuntu1.1) bult-in shell (ash)
Enter 'help' for a lost of built-in commands.
(initramfs)