Musclenerd has just updated the Redsn0w to version 0.9.11b2 to downgrade iOS 5.1 / 5.1.1 to iOS 5.0.1/ 5.1 for mac and windows. The new redsn0w 0.9.11b2 can be used to restore firmware for the iPhone 4S with build “9A406” iOS 5.0.1 flavor of 5.0.1 for the iPhone4S.
In the earlier version released yesterday, redsn0w 0.9.11b1 many users were facing issues in restoring iPhone 4S on iOS 5.0.1 with build 9A406 and musclenerd has announced to release an updated version to fix the issue with iOS 5.0.1 9A406 users. The latest version will also support to downgrade the iPad 2 and iPad 3 as with beta 1 version.

You can download the redsn0w 0.9.11b1 from the link below and use the guide to downgrade iPhone 4S from iOS 5.1.1/ 5.1 to iOS 5.1 / iOS 5.0.1. You can now jailbreak your iPhone 4S on iOS 5.0.1 with redsn0w or Absinthe tool.
Download redsn0w 0.9.11b2 For iPhone 4S, iPad 2 and iPad 3
- redsn0w 0.9.11b2 for OS X
- redsn0w 0.9.11b2 for Windows (be sure to run in Administrator mode)
If you face any issues, do let me know in the comments below..
