03-11-2013 01:36 PM
Hi and Welcome to the Community!
Not knowing how you were performing this update, it's difficult to be precise with advice...there are multiple methods to do updates, and the failure recovery from each can be quite different.
If you are doing this via PC/USB, and you are at a stage where it is still running but the device simply displays the 507, then remove and re-insert the USB cable...sometimes, that can allow the process to continue.
A 507 means that there is no OS on the device...here is the official KB on it:
The recovery does require a PC/USB, and is documented in one of the linked KBs from that one.