https://www.idevice.ro/2013/03/19/tutorial-jailbreak-iphone-3gs-si-iphone-4-pe-ios-6-1-3-folosind-redsn0w-0-9-15-beta-3windows-mac/
Tutorial: Jailbreak iPhone 3GS si iPhone 4 pe iOS 6.1.3 folosind redsn0w 0.9.15 beta 3(Windows Mac)