Before your iPhone 4 had regular old Philips screws which you would have a tool with which you could use to open it up with just lying around the garage. Obviously this is something that Apple does not want you doing since they have switched the screw over to this new flower shaped screw. This is not just for the newer models, but also when you go in to get your iPhone fixed you will find that it has come back with a new set of screws. These pentalobe security screws, as they are calling them, have a flower shaped screw head so there is pretty much no way to just find a screwdriver to fit this screw and open your iPhone 4 anymore. For many of us this will make no difference, but for people whom like to open things up and play around with it a bit iFixit has come out with a liberation kit for your iPhone 4 at the small price of $10.

Sources: Gizmodo iFixit