Aporte original por: el_rika ,
If you Ipad has EVER been into a street service and had any part replaced, you wil NEVER be able to activate it again. The moment you updated it from ios 9 to ios 11, you turned it into a brick , as ios 11 doesn't allow anymore for apple devices with replaced parts (or refurbished devices) to activate. Go to that service again and if he can fix this, in ANY way, you're in luck buddy. My IpadMini2 is a brick in my drawer since last year.