A few hours ago, notorious hacker iH8sn0w, announced that he has found an exploit that can be used to downgrade iOS 5.1 to iOS 5.0.1. As you can see from his tweet, the downgrade will only work for all A5 devices. This will be extremely useful for anyone who has accidentally upgraded his iPhone to iOS 5.1.
iH8sn0w: Found a loophole in Apple's apticket system. Restored my iPad 2 to 5.0.1 from 5.1. Works on all A5 devices. :)
Downgrading iOS 5.1 to iOS 5.0.1 will enable many people to once again jailbreak their iPhone. Though exploits for iOS 5.1 jailbreak have been already found by some hackers, there is still not a jailbreak tool available. A jailbreak for the newest operating system is still under development by the iPhone Dev-Team.
SHSH Blobs Still Needed to Downgrade iOS 5.1
In order to downgrade IOS 5.1, you will need to have your SHSH blobs saved on Cydia server. If you have not done this then you are out of luck. Needing your SHSH blobs to downgrade iOS 5.1 has already been confirmed by iH8sn0w:
iH8sn0w: @praneet94singh SHSH blobs will always be required unless someone finds an untethered bootrom exploit.
Other Details About Downgrading iOS 5.1 to iOS 5.0.1
There are indeed some other things that should be known about the downgrade for iOS 5.1 to iOS 5.0.1. The most important thing that you should know, is that if you downgrade iOS 5.1, the baseband will still remain the same as before. Just like downgrading any previous firmware, this downgrade will only help you in downgrading the firmware, not the baseband.
Another thing to keep in mind is that this downgrade is only for A5 devices. If you want to downgrade iOS 5.1 on A4 devices, you can do this using iFaith. iH8sn0w also said that this downgrade should also work with the new iPad, whenever new firmware will be released; Great news for the jailbreake community in the future.
Stay tuned for updates! A tutorial on how to downgrade iOS 5.1 to 5.0.1 on A5 devices will be here soon!Contact Us for News Tips, Corrections and Feedback