USB booting :: Strange Colors

I had that same problem. But eventually I discovered that my monitor was only cabable up to 640x480 with 16bit colors. If I set more colors it went bogus. Readbale but colors were mixed badly.

So have you tried to use higher resolutions with 16bit colors? Or even less colors?

You can check which modes are supported by runnins Xvesa -listmodes

If you can't get a solution you want, you might want to try a full xserver - see XFree86 extensions.

original here.