Can I safely downgrade my Sony Xperia SP? I just upgraded my Sony Xperia SP (C5306) with Sony's horrible tool from 4.1.2 to 4.3 (build 12.1.A.0.XXX to build 12.1.A.1.207), but my phone now runs worse, and I don't like the changes at all!  Unfortunately, it seems there is no legal/official way to revert.  

I am not computer illiterate, but have no experience with rooting and such, and everything I read warns about possible bricking and whatnot, so I am a bit weary of jumping into something and breaking my phone.  

Is there something I can do that is safe to return to the old OS?  I'm so bummed as I seem stuck with this OS and I've deleted all my stuff when I tried doing a factory reset. :(  

Thanks for any help!!!
Is there something I can do that is safe to return to the old OS?


Easy answer: No, there is not. You should flash it manually using, for example, flashtool (you don't need root).

Here is great guide which may help you.

Chance, that you hard brick your phone is really small If you flash right firmware.