Well, are you sure you didn't short any other ecu pins? Sounds like you could have and killed the mcu. Flashing in boot mode is how you recover a bricked me7 ecu, so if the ecu wont write then the ecu was damaged or the cable is somehow bad. Find another ecu and try flashing that would be my advice, that would eliminate the cable from being the problem.
I'm sure i didn't touched anything else. It was the same thing i was thinking about, it may be that I fryed the ecu. I ordered a new one, hoping that it will work.
Thank you for your replies, I'll update you when the courier delivers me the other ecu.