These are TorX screws (6 point) that are "tamper-resistant" - they have a little nub in the center which prevents a regular TorX driver from getting in.
You can get a special tool for this; however, I have managed to open up four iOpeners using a flat blade jewellers screwdriver offset to one side (if you imagine the points number 1 through 6, this is like spanning points 1 and 3 (whereas normally you'd go from 1 to the oppposite point 4).
You do this at your own risk, however!
