A demo unit came back from the customer and would only boot to maintenance mode, returning some errors about missing files. I tried doing a factory reset (to 6.0.4)but was unsuccessful. Normally at this point you would open a ticket with Palo and begin the RMA process but i was able to revive the box using the following procedure (definitely faster than waiting for RMA):
1) From maintenance mode, run the check disk utility on ALL partitions(in my case there were errors on the logs partition). Let it fix any errors that it finds (I attempted a factory reset again at this point an it still failed, Palo was ready to RMA but I wasn’t).
2) From the Factory Reset sub-menu, choose Advanced. Password = MA1NT
3) Choose 6.0.0 and reset again. This time it should succeed.
5) Run Factory Reset again, this time normally (6.0.4 in this case). Should succeed