Sony has added a new feature to its recent Xperia mobile devices called My Xperia Theft Protection or MXTP, it’s present in devices like the Xperia Z4 Tablet, Xperia C4, Xperia Z4/Z3+ and the Xperia M4 Aqua. The feature provides users with bootloader level security thus making it impossible for someone to wipe the device or flash a new ROM without first entering the required credentials. Apparently the My Xperia Theft Protection feature can brick devices if you’re not too careful with it.
Newer devices from Sony ask users if they would like their bootloader locked or unlocked straight out of the box, if the status line says “Bootloader unlock allowed: Yes” it means that the bootloader is locked and can be unlocked at any time.
Once MXTP is enabled on the device the option changes to “No,” which means that the bootloader can not be unlocked once My Xperia Theft Protection has been enabled.
The bricking issue comes up when users enable MXTP on a device that already has its bootloader unlocked. The feature then tries to block unlocking of the bootloader and this causes a malfunction on the device possibly bricking it.
The company is aware of this issue and has modified a warning on its website cautioning people that enabling My Xperia Theft Protection on a device that already has its bootloader unlocked “might cause the device to malfunction.”
So if you do want to take advantage of this feature ensure that the bootloader has been locked before enabling MXTP.