While booting up, the appliance hangs at "Freeing unused kernel memory"
It is possible that the disk has become corrupted.
Resolving the problem
Use the steps below to check for disk errors (only for v5.x):
1) Download and burn a Linux live CD. (ex. Knoppix)
2) Put the Linux CD into the appliance and boot from CD.
3) Run the following command to check for errors on sda1, sda2, sda5, sda6, sda7:
‘badblocks –n -s -v /dev/sda#’
4) If any of the above commands reveal disks errors, then run the following command to correct the errors on that drive
‘e2fsck -f -c -p –v <drive>’
5) After fixing all the disk errors reboot the appliance and try to boot into the CIOS (Cast Iron Operating System).
If these steps do not help address the issue, contact IBM Support.