New answers tagged bootloader-lock
It doesn't wipe the OS (the system partition), only the user data. It's a precaution so that an attacker can't install a new OS to get around Android's security protections on your data. See Why does unlocking the bootloader wipe phone? for more details on why. When you first boot the device after unlocking the bootloader, if you don't flash a new OS right ...
Just relocking won't work, you need to restore the TA partition (which contains DRM keys for Bravia Engine) that you must have backed up before unlocking your bootloader.
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