The iPhone Dev-Team has announced plans to release their 'backup plan' untether this holiday weekend.
Over the Christmas weekend we’ll be releasing a version of redsn0w that implements the 'backup plan' to the 4.2.1 untethered jailbreak. We’re seeking your help to test this redsn0w and find any bugs before we do a general release!
(If you have an iPhone 3G, or an old-bootrom ipt2g or iPhone 3GS, you already have an untethered jailbreak! Just use the latest public redsn0w.)
To keep things manageable, this will be a Mac-only test program. We also request that any volunteers *NOT* need the ultrasn0w unlock (in case things go very wrong).
Right now, the 'backup plan' requires that you have the 4.2b3 IPSW on your Mac, and that Cydia has your 4.2b3 SHSH hashes. Please don’t pirate that 4.2b3 IPSW! (We’re also working on a way that this technique might apply to all those with 4.1 IPSWs, but that’s not the first goal right now.)
If you fit all the above qualifications, please follow @redsn0w_testers on twitter for announcements, and use the comments section here for feedback. Thanks very much for your help, and Happy Holidays!
We'll provide you with more information and instructions when it becomes available.
Comex is still working on his preferred untether but it looks like it won't be available by Christmas.