I broke one screw and had to cut the head off using a dremel. Luckily it was only one and there was no problem leaving the hole alone because it was the one just above the battery, and the others hold the frame really well.

So, DON't use the T4 Torx screwdriver that comes as a gift with some batteries sold in eBay.

I used a T5 from a higher quality set that I had lying around, and it worked like a charm.