Make sure your screwdriver fits tightly, no slop.... Use a lot of pressure and SLOWLY bust it free. If you feel the driver rounding the screw, stop.

I normally don't worry too much about stripping screws / bolts as I'll just re-dirll and tap, but these little bastards are so small, I doubt I'd ever find a tap or drill to fix it. (and I have access to a machine shop).