I have the 4S, so I get turn-by-turn navigation without the need to jailbreak, but I wonder if there is a way to enable turn-by-turn voice directions on an iPhone 4 running iOS6 without downloading a third-party navigation app. Is it as simple as editing a property list, or are there any files that enable turn-by-turn navigation on the iPhone 4S that aren't available for the iP4?