“My Xperia Theft Protection” (MXTP) is one of the new features found in the more recent devices of the Sony Xperia line – namely the Xperia Z4/Z3+, the Xperia Z4 Tablet, and the Xperia C4 and Xperia M4 Aqua. MXTP is unique in such a way that it offers bootloader level security to your device – in layman’s terms, this will not allow a thief to just wipe your device clean or flash a new ROM without knowing your Google login.
That’s all pretty neat, we think. Sony already has a feature out of the box for its newer devices that ask if you want the bootloader locked or unlocked – a status line will say “Bootloader unlock allowed: Yes”, this means your bootloader is locked, but can be unlocked. Once you enable MXTP, the option will change to a “No”. From here, you can only allow bootloader unlocking if you disable MXTP, which will require you to input your security details.
The problem occurs when you have already unlocked your bootloader, and then you suddenly think of enabling MXTP. In this situation (bootloader already unlocked), the MXTP will then try to return your status to disallowing the unlocking of the bootloader. Apparently, this causes a malfunction on the device, most likely causing it to be bricked. Some people have had their Xperia Z4 Tablets bricked and unrecoverable before they realized it was MXTP that was the cause.
Sony is now apparently aware of the issue and recently modified their warnings to their Unlock Bootloader website, warning people that enabling MXTP on an already unlocked bootloader “might cause the device to malfunction.” For those of you who discovered this the wrong way, we feel your pain. For those of you who are not yet informed, be informed now.