I'm thinking of upgrading my 4S from 5.0.1 to 5.1.1 after reading about RedSn0w 0.9.15b1 (released Oct 2012) which allows "restore from any 5.x iOS to any other (up, down or the same) 5.x iOS on all devices as long as you have the correct blobs". The thing is I do not have any saved blobs. I'd like to do this and still being able to restore my backed-up data from iTunes after upgrading. Can I use the IPSW from here instead? Is this even possible?
answered 18 Dec '12, 19:52