Apple released iOS 4.2.1 GM for developers and it’s already leaked in the wild. Earlier today we posted a guide to Jailbreak iOS 4.2.1 iPhone 4, 3GS, 3G, iPod touch, iPad With Redsn0w. If you downloaded those Beta builds and now you want to go back to iOS 4.1 or lower for whatever reason, we created a step by step guide to downgrade your iDevice from iOS 4.2.1 beta to iOS 4.1
Note : iOS 4.2.1 is still in Beta and you needn’t to edit your host files to bypass Apple ...