Fully updated iPhones can be permanently bricked after undergoing unauthorized repairs.
iPhone 6 owners said that their handsets stopped working after updating to iOS 9, according to The Guardian. Users reported that their phones were bricked after the software upgrade and that attempting to restore the phone led to an error message.
This problem affects phones that have had their home button fixed by a non-Apple repairman. There are also reports that this error affects users who ignore hardware damage and continue using the device without repairing it.