Today Sherif Hashim Tweeted out some pictures and a video showing that he is working on the baseband downgrade from 6.15.00 5.13.01.
He also shared a video on Twitter showing the process of Downgrading the baseband.
Original Link .
As you can see in the Video the baseband is flashed with Errors. Till now no solid words are said on the release of the Method or any thing yet. Sherif Hashim is working on the method to make it work without Errors.