I've recently upgraded my iphone 4 to the iphone 4 S as my old iPhone has had more than its fair share of fights with gravity. The process to migrate between the data from one iPhone to another is as simple as backing up your old phone with iTunes, connecting the new phone and then restoring the backup. That process was easy and has been well documented with apple's support site.

What I was fearing however, was wiping the data clean off my old iphone in order to resell it. I was expecting using a 3rd party hack or some other utility to do this necessary job but I was pleasantly surprised how easily I could reset my phone.

The official support document from apple guides you thru the different device combinations. But for the iphone, the steps are as follows:

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