In this tutorial I will show you how to Jailbreak your iPhone 4 on iOS 5.1. Before you proceed to actual tutorial keep in mind that this is tethered jailbreak which means that you will need to connect your iPhone with your Mac computer and re-run RedSn0w to boot your iPhone 4 into fully operational state every time your iPhone loses power. Also let me note that this Jailbreak will not work on iPhone 4S and that iBooks will not work correctly until iPhone Dev-Team implement a patch that will fix this.