All the groms are allready dumped. expect pss64.
There aren't 12 roms on the pcb. only 6 mapped hi and lo. CE lines are connected together and after that to some logic ICs. OE lines go to the GAL/EPL.
Replacing the roms it's not easy at it seems. The easiest way it's to replace a rom with something equivalent. Like donkey kong with donkey kong 3.
The FX chip in pss61 uses oe from roms 1 and 2.
The grom has a checksum at the end and it's xored by FF. The graphics are compressed.
The biggest progress i've made was to add 3 games on a pss62 pcb. I've abandoned the project a long time ago. (I was hoping to get 6 roms working, but no luck).
I don't remember, but I don't think it's possible to add rgb. It's been a while and I might be wrong, but the snes outputs svideo to an overlay ic (no datasheet available, but there a datasheet to simmilar one) and that ic doesn't support rgb.
PS: If you compare the boards, you'll see that on pss63 and 64 some 74 chips are missing. A few of them are for fx/dsp and i believe the rest of the missing ones are for the sram (128k sony). It's weird that they are present on pss62 (maybe had an extra of pss61 boards and used them to make pss62...)
The menu text is located in the attract rom and it's also compressed. There is a tool made by the guy that made lunar magic (forgot his name) and with that i managed to decompress some tiles, but when i recompressed them, they displayed as garbage.