After MuscleNerd has declared about the new amazing Redsn0w jailbreak features, he has been asked about the downgrade for 6.15.00 baseband on iPhone 3GS and 3G after using ultrasn0w, he points that the work on the downgrade issue won't start only after the release of iPhone 4 baseband 2.10.04 unlock which expected to see the light in less than a month.

In case you have unlocked your iPhone 3GS / 3G by flashing iPad baseband 6.15.00 with ultrasn0w 1.2 on iOS 4.2.1, and have issues while restoring your device, here is Sherif Hashim the guy behind ultrasn0w unlock tool, has posted a simple guide showing how to restore your iPhone 3GS / 3G to avoid iTunes errors.

This post will help those who unlocked iOS 4.2.1/iOS 4.1 on their using ultrasn0w 1.2 and were experiencing GPS issues. The iPhone Dev Team have acknowledged the unfortunate fact of ultrasn0w causing loss of GPS for the iPhone unlockers.