I have an iPhone 4 GSM running iOS 5.0.1 JB which was done thru redsn0w. With the new untether out for 5.1.1, I want to upgrade. I have seen in some places that I can just update the iOS version via iTunes and it will work and stay jailbroken. Other places say that I have to restore and rejailbreak. Which is true? And what software should I use, like redsn0w or absinthe?