I switched the sign of a golden iphone 6 plus for a 6 Plus Graphite, and the phone worked perfectly, except for the Touch ID. However when I tried to upgrade to firmware 8.4 by itunes, I received an error and could not complete the upgrade, and also can not restore. Also disconnected the touch ID flex, and redid the restoration but also not finish the restoration. The device now so the league in DFU mode, and not yet tried to destroy the plates is trying to update. But my biggest doubts and understand why this mismatch when switching the plates even though the same unit.