If you have ever heard the expression there is no free lunch, you likely know what that means. Like with most things in life, sometimes you need to give a little to get a little. This is normally the case when it comes to bootloader unlocking of most devices, regardless of manufacturer (keyword here is “most”…. I had to say this before Samsung fans jump out of their chairs with pitchforks :p). The likes of Asus and HTC normally offer official methods for unlocking their bootloaders. In order to do this, you must turn over your soul… err, I mean your warranty, just for that bit of extra functionality (and in the case of HTC, that is just a bit of extra functionality as there are still several things that are blocked even after a bootloader unlock). There are of course other manufacturers that offer these unlocking services as well, which give you a far richer experience and more freedom for the same price. One such case is Sony and their Xperia line up. Many moons ago, Sony came up with an official tool to unlock your bootloader, much like the aforementioned manufacturers have done, and yes, they also take your warranty along with the unlock right. However, you gain full control of the device by doing it, or at least nearly full control as you lose a little something in the process… Unlocking the bootloader on any Xperia device that supports it will also wipe out the included DRM (Digital Rights Management) keys embedded in the device, which are essential for a few software bits to work on the Xperia .
The newest addition to the Sony lineup the Xperia Z, suffers from the same predicament. Unlocking the bootloader will effectively wipe your DRM keys, leaving you with a non-functional Bravia Engine 2, TrackID, or OTA update capabilities, as well as a few other things. If you have not yet unlocked your BL, but are considering doing it, you must read the guide made by XDA Forum Member rickwyatt. The member provides an easy to follow guide with tools to help you back up your TA partition, which contains (as you may have guessed/known) the DRM keys. Being able to back up the TA partition effectively gives you a “time machine” allowing you to go to the point before you unlocked your device. Restoring the partition will do two things: it will restore your DRM keys as stated earlier, and it will relock your bootloader. Mind you, this can only be done BEFORE unlocking the BL because your TA partition WILL change, and backing up someone else’s will instantly kill your device, hard brick style.
While this is not exactly the solution a few of you were waiting for to get BE2 working again on your unlocked Z, it is a step in the right direction. Just keep in mind that it is always advisable that if you are going to restore your TA partition from your backup, you should be on a completely stock rom/kernel. There are reports from some people in the thread who have had soft bricks by restoring over custom ROMs and/or kernels while others have had very few if no issues at all.
Take it for a spin only if you have not unlocked your device yet. The thread is a good discussion and is filled with lots of useful information that might prevent you from making a mistake in the process. Please make sure that you read and understand what is going on before diving in.
This wont work if you Unlocked your bootloader already because you have already changed you TA partition. also don’t flash someone elses TA it will hard brick your phone