Originally posted by boriscleto . . . if you really want to tinker . . . you'll need a #00 Phillips head.
Just a caution: Those screws that look like Phillips 00 and 000? They aren't. They're JIS cross-heads and life's a lot simpler with JIS screw driver bits.
Search "JIS screw drivers" -- Amazon's got 'em and whether you do this only once and run into trouble, or intend to do it often, it's worth your sanity to do it with the JIS tools so you don't risk stripping a screw head.
Otherwise, if
gentle torque with the common Phillips jeweler-type tools doesn't work, file a flat-blade bit to the correct angle. Sooner or later, you'll be sorry if you don't as the Phillips bit makes a great roto-rooter in a tight JIS screw. You can see why here.
H2