My son's friends came over with his own disc and updated my CfW 3.55 to 3.72 :'( I've been searching for a downgrade method within my skill set and came across the ps3key/e3 flasher/factory reset method. Is this effective? I can't find a clear description of what's needed. Do I just need to purchase the ps3key and make my own e3 drive with usb stick, or do u have to purchase both? Any help would be greatly appreciated, thanks in advance.