is it possible to update from os 3.1.2 to os 4.0? my iphone is jailbroken with cydia also Rock both apps are in order. however I like to update to 4.0 and take some avantage of the 4.0 os. as you may know the latest os on itune is 4.1 to which no jailbreak app is available. i would be highly appreciate is someone can walk me thru the process.