A few console manufactures decided to use GameBit security screws for their consoles and/or cartridges, most notably – Nintendo, who use them for a lot of their retro consoles and cartridges. This page covers the alternatives to buying the proper parts if you just want to do one mod quickly.
If you’re going to be doing lots of taking apart, then you’d better buy the proper GameBits, they come in 2 sizes, 4.5mm to open up consoles (and Mega Drive carts), and 3.8mm to open up SNES carts. Check out some of the suppliers on the Links page.
If you just want a Gamebit to take one thing apart, you may get away with making your own. If you’ve got a spare flat screwdriver, and a Dremel type tool, you could cut the screwdriver tip like this:
Alternatively, and much easier to make but not as strong, you could empty a BiC biro, the end of the biro where the nib goes is a narrower than the non-writing end, heat the narrow end up – hold it over a gas flame or something.
The plastic heats up and goes very soft (or catches fire – let it burn a little and blow it out), DON’T touch it! Push the soft warm plastic onto the security screw, push it hard enough so the plastic forms around the shape of the screw head. Now remove the pen from the screw, let it cool down (you could run some cold water over it), and hey-presto, it should be strong enough to use as a screwdriver.
It’s not very easy to take a decent photo of a melted biro! See how good a fit it is, look how well it holds the screw.
It probably won’t last very long, and you may have to repeat the heat/mould cycle if it’s a stubborn screw.