I am using Lightweight Portable Security, and I need to add the FGLRX driver so I can boot it on my system (R9 200 is keeping it from booting). Is there a workaround? Is there a way I can just add the files to ISO image?
Well in first place i will suggest to use any other distro that one featured by the US DoD (and probably with the intrution of the NSA), if you want security use tails.
Leaving this apart, the thing is fglrx is a propertary driver, so is hard to include it in a distro (and i don't have any clue about LPS base). Maybe you can just add the binary, reburn the iso (if using a CD), and execute the installer every time you start, this suposing that at least you can boot in text mode.
In case you can't boot even in text mode, definetly you should change the distro (ati generic driver works even in ubuntu).