I own a Motorola Razr HD xt925.
First of all, I have a big problem of hardware. The power button does not work, which makes everything harder, but fastboot can fix almost anything.
The device had installed Cyanogenmod 10.1.3 and then I updagraded to CM11 nightly from OS directly. It worked almost perfectly until now.
Today I was using the phone and suddenly the screen went black. As usual, I had to disconnect the battery to turn it off and connect the data cable to bring it back to life.
Since then it is in a boot loop.
I wiped everything, reinstalled 10.1.3 cyano, updated the modem, almost everything and still happening the same.
When I try to downgrade it to the stock rom the phone says
preflash validation failed for gpt