Sorry, can't help but I can sypathize with your dilemma. I have run
across a couple of Torx screw sizes for which there don't appear to be
any screwdrivers for. One is the Palm Pilot, the other, a DeWalt
battery charger. Can't take them apart.
There are 3 common sizes of square Robertson screwdrivers, and the
smallest is quite tiny, not that commonly used. The bits are tapered
slightly so fit a wide variety of square holes. They have been around
since the '30's, are far superior to the Phillips, grip the screw
really well, but were declared un-American. The Canadian inventor died
in poverty. Then, when robots in the US and Japan began fumbling with
useless Phillips screws, the equally PITA Torx screw was invented. Now
you need 12 more screwdrivers to get the job done. And you're still
missing a few.