System ROM



BIOSes are ROMs containing the initial program executed by NeoGeo systems. They are present in all hardware types.



AES BIOS
128kB. NEO-EP0.

MVS BIOS
128kB. SP-S2. Different names according to nationality.

CD/CDZ BIOS


512kB (1MB ?). One chip that contains Z80 and 68k programs, PCM sound, and graphics data which are copied to the corresponding DRAMs at boot time.