Apple 4.3.1 How To Downgrade

If you're looking to downgrade from 4.3.1 try this...

Apple launched their new iOS 4.3.1 for the iPhone 4, iPhone 3GS, iPad 2 and iPod Touch 4G / 3G. If you were one of those unlucky ones who actually upgraded to the new iOS 4.3.1 and now want to downgrade your IOS firmware, please follow the guide below.

The below guide will help you downgrade your iOS device to iOS 4.2.1, 4.1 or 4.3. This guide is compatible with the following iOS devices:
iPhone 4
iPhone 3GS
iPod Touch 4G / 3G and
iPad 2 / iPad

Instructions:
Downgrad iOS 4.3.1 to 4.3, 4.2.1, 4.1 on iOS devices [Full Guide] - GeoHot