Jailbreakers Beware: iTunes Will No Longer Restore 3.1.2, But There’s A Workaround
Attention jailbreakers: We’ve just received word from BigBoss that Apple stopped signing iPhone OS 3.1.2 restore packages today, making it impossible to restore to 3.1.2 without a workaround. This only affects the iPhone 3GS, the third-gen iPod touch, and late-model, second-gen iPod touches; other iPhone OS devices do not use signed restore packages.
So what does this mean? Well, because Apple released iPhone OS 3.1.3 earlier this week, the Apple servers will only let you restore to 3.1.3, even if you have an older 3.1.2 restore package lying around. And since the current jailbreak tools only work on 3.1.2, updating to 3.1.3 will leave you jailbreak-less — at least for the time being. But wait, there’s a workaround!
Apple signs restore packages based on each iPhone’s unique ECID SHSH, making it near-impossible to restore an iPhone using anything but Apple-approved software. However, Cydia has the ability to save that info so you can authenticate with Saurik’s server. I’m paraphrasing, but you can read all the details on Saurik’s site.
The point is, if you jailbreak while still on 3.1.2, make sure Cydia has your ECID SHSH on file before attempting ANY restore. Once it’s on file, you need to modify your hosts file so that iTunes looks at Saurik’s server instead of Apple’s server. Then you can restore to 3.1.2 without a problem.