I was trying to take my wife's XT926 back to stock and think I may have bricked the device. The phone was on 4.1.2 and was rooted and I ran this utility http://forum.xda-developers.com/show....php?t=2757285
The phone is now stuck on the AP Fastboot menu and here's what it says:
Device is Locked. Status Code:0
Transfer Mode: USB connected
No valid PIV block in SP for system
piv validation failed (system)
fastboot Reason: Boot Failure
I cannot get into the stock recovery to do a factory reset. I've tried holding down the volume up button when powering on and it brings up the boot menu, but the phone always goes to this screen no matter what I select.
Not sure if I did something wrong, but I thought I followed all of the instructions. I've done plenty of rooting and tinkering with other phones and this is the first time I've had a problem like this.
EDIT: This was the only thing that worked for me: