1. Follow the instructions on [Sony’s official unlocking website](http://developer.sonymobile.com/unlockbootloader/unlock-yourboot-loader/) to unlock your bootloader.
1. Use your code to unlock the bootloader of your device:
`fastboot oem unlock <your_unlock_code>`
1. Since the device resets completely, you will need to re-enable USB debugging to continue (Settings->About Phone->Build version, and then you can go to Settings->Developer opptions to enable USB debugging).