Well, I have some Sega Saturn HST-0004 and it uses the mother board VA 0.5, I like the animation on the Hi-Saturn bios and do have eproms and burner the bios is DIP so I decided to put that bios on my saturn. Well burned ok, checked chip ok, no go, just led and lases try locating disc but black screen. The saturn had the bios MPR-16606A-T mask rom and tried to dump it no go, just fffffff both on top 2007 and the GQ-4x. Well, seen in some place somebody said the bios should be byte swaped to work did it and didnt worked. What the hell?!?! :dammit: Now I am questioning myself what is whrong??? Am I missing something? Btw the original bios put back in the socket works normally ( so the console is working ). Anyone can give some advice?? Thanks!
Perhaps the pinout of the MaskROM is not standard. That would explain why you couldn't read the MaskROM properly in your programmer and why the EPROM didn't work.
The pinout is standard. But it's not that of a 16bit 512KB eprom. Use the pinout for the 27C160. And use a 27C160 to write the other BIOS you want. (mirror the ROM 4 times, to fill the chip.)