Sony is one of the manufacturers that best supports its users. While both do their best to make it difficult to unlock their device's bootloader, the Japanese company publishes a video with the step-by-step tutorial of the process. After that you can root your Xperia and flash the custom ROM of your choice.
Among the major manufacturers, Sony was the first to launch an informational page (unfortunately only in English) about upgrading their devices to the new version of Android, a good example followed by Motorola (also in Portuguese). Now Sony developers teach in video how to unlock Xperia bootloader. Both the video and the explanatory page are in English, but the tutorial is very easy to follow:
Please note that unlocking your Xperia bootloader will void your warranty. That said, flashing a ROM on an older device is the best way to give it new life, and it's good to see that such a process can also be encouraged by a major manufacturer.
Have you ever rooted your Xperia?
(tagsToTranslate) sony (t) xperia (t) bootloader (t) unlock (t) video