Upgrade 2.1.5 to 2.2 on Watchguard X8500 & X5500 Fail

[Whitey436]

Tried using the upgrade from the PFSense console.  Seemed to run for a bit but never came back to life.

When I loaded the IMG directly to the CF card and tried to load, it continues to reboot.  Completes POST then starts 2.2 load but reboots over and over in this same cycle.

Just posted as an FYI sounds like the cause may already be identified.

Problem I am now having is I cannot get 2.1.5 to load any longer.  Completes POST, shows PFSense, OS Loading on front display and nothing else occurs on console.
Tried reflashing BIOS, wiping and rewriting CF 2.1.5 image, no luck.

Any ideas?