SHA1 Sum = 9e8ce7d4eb79b5f839efa0233893ef1a6a5e3c5c

WARNING WARNING — ultrasn0w users don’t update yet! See a few paragraphs down!

The 4.3.1 untether exploit comes courtesy of Stefan Esser (@i0n1c on twitter), a security researcher based in Germany. Stefan has a long history of vulnerability research, and ironically his first contribution to the iPhone jailbreak community was improved security — last year he beat Apple to the punch and implemented ASLR for jailbroken iPhones with his “antid0te” framework. We’re happy to see that Stefan then turned his iPhone attention over to an untethered jailbreak exploit!

The 4.3.1 untether works on all devices that actually support 4.3.1 except for the iPad2:

iPhone3GS
iPhone4 (GSM)
iPod touch 3G
iPod touch 4G
iPad1
AppleTV 2G (PwnageTool only for now)
The reason the untether won’t work as-is on the iPad2 is that it requires a bootrom or iBoot-level exploit to install, and the iPad2 is not susceptible to either the limera1n or SHAtter bootrom exploits.

WARNING WARNING — ultrasn0w users don’t update yet! We need to first release an update to ultrasn0w that fixes some incompatibilities when FW 4.3.1 is used on the older basebands supported by ultrasn0w. And remember once we do fix ultrasn0w for 4.3.1 (we’ll announce it here and on twitter), you must only get there via a custom IPSW from PwnageTool, Sn0wbreeze or xpwn! Don’t ever try to restore or update to a stock IPSW, or you’ll lose the unlock!

For everyone else, redsn0w is the easier program to use (and redsn0w runs on both Mac and Windows). Please check out places like iClarified for some excellent guides on how to use both PwnageTool and redsn0w.

iPhone OS 3.0 support

Installer Beta included
supports 2.0.1 firmware from apple