Emulators:

Nintendo Entertainment System - (NES),
Super Nintendo Entertainment System - (SNES),
Game BoyClassic - (GB),
Game BoyColour - (GBC),
Game BoyAdvance - (GBA),
Sega MegaDrive (Genesis) - (GEN)

Roms:

NES (768 + Covers)
SNES (770 + Covers)
GB (121  + Covers)
GBC (511 + Covers)
GBA (135 + Covers)
GEN (351 + Covers)

Installation:

Install emulators via "install package file"
Copy the Folder "ROMS" from your extern to intern hdd via multiman

dev_hdd0/ROMS/snes  -  super nintendo entertainment system
dev_hdd0/ROMS/vba    -  gameboy/gameboycolour/gameboyadvance
dev_hdd0/ROMS/fceu  -  nintendo entertainment system
dev_hdd0/ROMS/gen    -  genesis/mega-drive

Done!!!

Notes:

game-boy-classic roms named "0gb_"
game-boy-advance roms named "zz_"
game-boy-color roms named normal