I have an Xperia Z and recently I unlocked the bootloader. However now I cannot install (upgrade) to the Lollipop Android 5.0 (10.6.A.0.454) from Android 4 (10.5.1.A.0.292) through the Sony website. I always get the message "cannot be installed because I have an unlocked bootloader".
Please advise on a step by step process to lock the bootloader again if possible or advise on how to upgrade to 5 version.
Please make it for dummies because I am not experienced or a developer whatsoever.