APRIL 4th UPDATED : iOS 4.3.1 jb now available here http://www.youtube.com/watch?v=z8EyxqVgpoc -------------------- Recommended for : Ultrasn0w unlocked users who want to maintain their baseband but want to update to the newest iOS firmware 4.2.1 (if this doesn't sound like you, why not just use the EASY 1 click alternative here http://www.youtube.com/watch?v=mpBh94nGBps) Sn0wbreeze (for Win): http://tinyurl.com/49ks5rr PwnageTool (for OSX): http://tinyurl.com/6a4mh5o If you get 16XX error do this : http://www.redmondpie.com/how-to-fix-1604-1601-1600-16xx-error-during-ios-4.2.1-custom-ipsw-firmware-restore-in-itunes-with-ireb-rc3/ ----------------------------- Special Thanks to - iPhone Dev Team for PwnageTool - iH8sn0w for Sn0wbreeze - Chronic Dev team for exploit http://facebook.com/iPhoneArena http://twitter.com/iPhoneArena NOTES : -This works for iPhone 3gs, 3g, 4, Verizon 4 - you can also use this for iPhones with flashed 06.15 baseband so you can restore with this cfw.