I had the same problem, what ive done is take the battery out connect it to the pc (XS++ is running) and hold C(logically.lol)and put batterie back.my phone wasnt recognized but after i put it away and start it agAin --white screen.THen take the battery out agaIn and hold the power button while putting back the battery. i dont know what happend (if the gdfs was automatically repaired by the phone, or what ever happend) but now my phon worked again (and i now never will RE-write my gdfs again .lol)