Downgrade 3GS/3G 06.15.00 to 05.13.04 Baseband for GPS + ultrasn0w

iPhone Dev Team announced baseband downgrade option in new redsn0w 0.9.14b1 , to get rid of iPad’s baseband 06.15.00 on your iPhone 3G & iPhone 3GS. After downgrading you can use fully supported GPS which you are not able to use on 06.15.00 iPad’s baseband. This downgrade is not supported on iPhone 4 & iPhone 4S [...]