Full credit and courtesy to Stefan Esser (Twitter handle: @i0n1c) for handing over to the Dev Team the untether exploit he discovered on Apple’s latest firmware, iOS 4.3.1.
Except for iPad 2, the latest version of Redsn0w (0.9.6RC9) is capable to jailbreak iOS 4.3.1 untethered for the following iDevices:
- iPhone 3GS
- iPhone 4 (GSM)
- iPod Touch 3G
- iPod Touch 4G
- iPad (first-gen)
For baseband unlockers, you are advised to stay away from Redsn0w and make sure not to update to stock iOS 4.3.1 firmware as it comes with a new basebands: that is 5.16.01 for iPhone 3GS and 4.10.01 for iPhone 4. Such basebands are still not unlockable with the latest version of Ultrasn0w just yet.
Redsn0w 0.9.6RC9 works both in Windows and Mac, and you can refer to the download links below.
Redsn0w 0.9.6RC9 for OS X
Redsn0w 0.9.6RC9 for Windows