If you are an iPad2, iPad3 or iPhone4S owner and have upgraded your device firmware to iOS 5.1 and want to downgrade back to iOS 5.0.1, then thanks to the latest Redsn0w, you can do that. Before this release of Redsnow, it was not possible to downgrade firmware versions of A5 devices like iPad3, iPad2 or iPhone4S. This is made possible by implementing a hack by the team that allows A5 downgrades without a bootrom-level exploit. It was announced by the Dev Team in a blog post.
Starting with redsn0w version 0.9.11b1, those with newer devices (iPad2, iPad3, and iPhone4S) can join the downgrade fun too! Â In a radical departure from previous versions of redsn0w, it now directly supports restoring IPSWs to your device.