Is your iPhone 4 already running iOS 5.1.1 tethered? If so, MuscleNerd just sent out a tweet warning users not to attempt to use the “reset all device and settings” option in Absinthe, but instead to download the untether patch from Cydia. The Chronic Dev Team has released Rocky Racoon 5.1.1 onto Cydia/Telephereo, which is the untether jailbreak based on exploits discovered by Pod2g and Planetbeing. Rocky Racoon 5.1.1 will allow you to boot untethered without external tools like RedSn0w.
(Keep in mind that “Racoon” is an intentional misspelling, based on a previous tool.)
If you just jailbroke your iPhone using RedSn0w and Absinthe, this package will already be on your phone. The important thing to know that removing the package will remove your phone’s jailbreak if your device relies on Rocky Racoon for the untether. The Cydia page mentions the second and third generation iPads and the iPhone 4S.
Rocky Racoon 5.1.1 Untether is available for download in the Cydia/Telesphoreo repository, which is a default source in Cydia.
Let us know if you have any issues with the Rocky Racoon untether in the comments section below.