Downgrade iPhone 4S And iPad 2 From iOS 5.1 To iOS 5.0.1 Is Possible
By now almost every iPhone 4S and iPad 2 owner know that these two devices cannot be downgraded to lower iOS firmware version. The reason is pretty obvious–we don’t have an A5 bootrom exploit. But that’s not the case now, iH8Sn0w, famous iOS hacker and developer behind famous jailbreaking tool Sn0wbreeze shared something really interesting today on Twitter. iH8sn0w successfully downgraded his iPad 2 which is an A5 device (duh!) to lower iOS firmware version which was considered as impossible till now. According to his latest tweet he successfully downgraded his iPad 2 from iOS 5.1 to iOS 5.1 which is a really good news for people who upgraded their iPad 2 to iOS 5.1 and lost their jailbreak but this also raises a lot of questions.
The developer/ hacker found a loop hole in all A5 device let me repeat ALL A5 devices which allows iOS downgrade. Another important thing to note here is that you still need iOS 5.0.1 SHSH blobs saved if you want your iPhone 4S and iPad 2 downgrade from iOS 5.1 to iOS 5.0.1. So if you didn’t save your iPad 2 od iPhone 4S’ SHSH blobs while Apple was signing iOS 5.0.1 it’s not possible to downgrade your device.
A5 has been a tough cookie for jailbreak dev teams from day one, A5 processor was first introduced in iPad 2 and as of this writing we don’t have a low level bootrom exploit (hardware exploit) for A5 chip. Not having a bootrom exploit means that developers have to search for vulnerabilities in every iOS update to jailbreak it. All A5 jailbreaks released till date which includes JailbreakMe 3.0, CInject and Absinthe are all user-land jailbreaks which works inside iOS itself and not the hardware of your iOS device.
It is still unclear how this new process/loophole works because it’s way too complex to understand. Couple of things which we know about A5 also includes that we cannot restore our A5 devices to lower iOS firmware versions after Apple stops signing a specific iOS firmware version. Another great thing which iH8sn0w mentioned in other tweets is that this “loophole” also works on A5X devices which means that we have opportinuities available for all new iPad 3 as well but of course it will work when we will get a new iOS version for iPad 3 because currently we have only one iOS firmware for iPad 3 which is iOS 5.1.
No release date has been issued by the developer himself.
So yes, now there is an iOS downgrade possibility on the horizon for all A5 devices. Moment of rejoices for A5 owner.
We will keep you updated on this, stay tuned!