How to Jailbreak iOS 4.2.1 GM on iPhone 4

Apple

How to Jailbreak iOS 4.2.1 GM on iPhone 4, 3GS, 3G and iPod touch with Redsn0w 0.9.6b2

Apple today has released 4.2.1 GM (gold master) for iPhone, iPod touch, and iPad. This build is actually available to developers but it can be…