It’s not been a long time since DevTeam updated one of their most used JailBreak tool, Redsn0w which fetches APTickets/SHSH Blobs for iOS 5.0.1. However, there is not much of a utility until something is released to make it work. Now, even Cydia does the same for you. If you are on iOS 5.0/5.0.1, open Cydia and checkout the top most line in green which also shows saved SHSH Blobs for iOS 5.0.1.
Anyhow, we shouldn’t be dependent on Cydia only. Because Redsn0w also saves APTickets/SHSH Blobs, you should save them using the tool manually. It would require you to take the device into Pwned DFU mode which can be done through the on screen instructions. MuscleNerd, a member of the DevTeam also claimed earlier that we would be able to restore to the same firmware in the future with the help of these APTickets.
The whole method would work with the help of a custom firmware. Once you have saved SHSH Blobs, downgrading to iOS 5.0.1 from the latest firmware wouldn’t be a difficult task. If you are stuck in recovery loop while downgrading to iOS 4.x, you can also try out iFaith from iH8sn0w. Unfortunately, iFaith doesn’t preserve the BaseBand of your iPhone 4 and the unlockers could lose the unlock forever.
Have you saved SHSH Blobs yet? Do it now!