-1 is a hardware error. Can't be fixed by DFU restore. Only Apple. And they'll be able to detect you opened your phone - so the warranty will be expired.
-1 can also be a baseband error generally speaking
-1 is a hardware error. Can't be fixed by DFU restore. Only Apple. And they'll be able to detect you opened your phone - so the warranty will be expired.
do they void your warranty if you change the back cover