Save your Sony Xperia device from bricking by not enabling ‘My Xperia Theft Protection’
In the more recent devices of the Sony Xperia line namely the Xperia Z4 Tablet, the Xperia C4, the Xperia Z4/Z3+ and Xperia M4 Aqua, it has added one more new feature known as “My Xperia Theft Protection” (MXTP). MXTP offers bootloader level security to your device, which makes it unusual in a way. In other words, this will not let a thief to flash a new ROM without knowing your Google login or just cleaning your device.
The out of the box feature has already been provided by Sony for its newer devices that asks if you want the bootloader locked or unlocked – a status line will say “Bootloader unlock allowed: Yes”. In other words, your bootloader is locked, however, it can be unlocked. The option will change to a “No”, once you enable MXTP.
If you disable MXTP, you can only let bootloader unlocking from here, which will need you to key in your security details.
The problem arises when your bootloader has already been unlocked, and then all of a sudden you think of enabling MXTP. In this situation, where the bootloader is already unlocked, the MXTP will then try to give back your status to disallow the unlocking of the bootloader. This causes a malfunction on the device apparently, most probably causing it to be blocked. Some people have had their Xperia Z4 Tablets blocked and could not recover it before they realized that the cause of it was MXTP.
It seems that Sony is now aware of the problem and they recently made changes to their warnings to their Unlock Bootloader website, cautioning people that enabling MXTP on an already unlocked bootloader “After unlocking your device, you should not enable My Xperia (found in the settings menu under security on some devices running Android 5.0) as this might cause the device to malfunction.”
So please ensure that you do not use the app if you ever want to unlock your bootloader, or if you already have. It is not clear as to what kind of “malfunctioning” Sony is pointing to in this statement. It could be something minor or it could block your smartphone.