I've found several threads on various forums with this problem, but no viable solutions so far.
I decided to give my 2013 N7 to my wife so I performed a factory data reset. It began the process then became stuck while erasing the userdata. After a couple hours it gave me the dead Android. I restarted and it was bootlooped. I then booted into bootloader mode to just flash the stock image files. While in fastboot, the first step I took was to unlock the bootloader. I was prompted with the "Yes" or "No" options. I choose yes then it hung at 'erasing userdata'. I left out overnight hoping it would eventually continue. No luck. I have never been rooted or ROM'd on this tablet. All stock. Has anyone found a fix for this issue? Thanks in advance!