This evening Apple released iOS 6 for all iDevices, and for jailbreaks there is a big problem. Those from the Dev Team explain on your own blog everything and in short the story sounds something like this: if you have any terminal released after iPad 2, then you can't go back to iOS 5.1.1 easily or at all after Apple will no longer sign SHSHs for that version of iOS. The detailed explanations sound something like this:
- in the case of iPhone 3Gs, iPhone 4 and iPod Touch 4G, you can restore at any time if you have available SHSHs for the version of iOS you want to return to. Regarding the jailbreak, for iPhone 3GS with old bootrom there will be an untethered jailbreak, and for the rest there will be a public tethered jailbreak only when Cydia becomes 100% compatible with iOS 6;
- if you have an iPhone 4S, iPad 2 (without blobs), iPad 3 or a terminal released after it, then you can restore to the version of iOS 5 that you already have installed. If you switch to iOS 6, you can't go back to iOS 5, but if you stayed with iOS 5, then you can restore to the version you're running, even if Apple no longer saves SHSHs;
- if you have an iPad 2 with blobs saved for ios 4.x or ios 5.x, then you can go back to those versions of ios, even if Apple no longer signs SHSHs for them. The problem is that you need blobs for iOS 4 and iOs 5 if you want to downgrade, so it would be better to stay with iOS 5.1.1.
Regardless of whether you can downgrade or not to a certain version of iOS, the baseband will not change. Soon the Dev Team will release new versions of the current peograms, but in the meantime stay with iOS 5.x.
- A4 devices and 3GS will always be downgradable (and jailbreakable) due to limera1n. The tethered iOS6 jailbreak for those devices (and untethered for old-bootrom 3GS) will be out when Cydia and other important pieces are all working properly
- iPad2 owners who have both 4.x blobs and 5.x blobs will always be able to downgrade to those versions, even once you come up to 6.0 and the 5.1.1 window closes (don't do that yet though!). You need both 4.x and 5.x blobs to qualify for the downgrade even if you only wish to downgrade to 5.x
- iPad3, i4S (and iPad2 owners who don't satisfy #2) will always be able to RE-restore the current 5.x OS that's already on their device. So if you're at 5.1.1 when the window closes (and you've saved your blobs), you'll always be able to RE-restore to 5.1.1 again. This makes the 5.1.1 jailbreak a lot less fragile — you don't have to worry about messing up your install with funky extensions or getting into a boot loop, because you can always RE-restore from 5.1.1 5.1.1 to again (or from 5.0.1 5.0.1 to again, etc.). Alcohol once you fall off the 5.x train by restoring to 6.x, you'll be stuck there until the next jailbreak.
