New RedSn0w dowgrade your 6.15 baseband==gsmfine.blog

If you have any questions or comments, please use our comments section below!

Here are the download links. Enjoy!

redsn0w 0.9.14b1 (OS X)
redsn0w 0.9.14b1 (Windows — run in Administrator Mode)

Source Dev-Team Blog - 0615 fun