Unlock bootloader Sony XPERIA

By unlocking the boot loader, it’s possible to put custom ROMs on your Xperia™ device. However, we recommend standard users not to unlock the boot loader, as it is not needed. We are proud to deliver great software experiences through our rigorously tested and official software releases.

How to unlock your bootloader
a) download and install latest Flashtool
b) start Flashtool and click on BLU button on the top
c) turn off your device and when Flashtool shows pop up window, connect device to PC with holding volume down button
d) Flashtool will check your device and than you need to connect your device once more, now with holding volume up button
e) click on get unlock key button, it will switch you to Sony website, here select your phone and hit continue
f) copy IMEI from Flashtool to Sony site and once more accept term and contidion, than click submit
g) copy unlock key to Flashtool window and than click unlock
h) your device is unlocked

How to relock your bootloader
a) download and install latest Flashtool
b) start Flashtool and click on BLU button on the top
c) turn off your phone and when Flashtool shows pop up window, connect phone to PC with holding volume down button
d) just click on relock button and your bootloader relocked for now