NaomiDIAG : A diagnostic bios for Naomi 1 & 2

[nem]

Is that even possible? @MetalliC?

Also, the only way to update a 1.XX firmware is by desoldering the flash chip. That's it.

 

[MetalliC]

@nem it was decade+ ago when I've been looking at DIMM 1.02 firmware disassembly, so I can't remember details...

but, in theory, if DIMM<->NAOMI interface have commands like POKE/PEEK to DIMM RAM - it might be possible to upload some our code there and patch DIMM firmware in RAM to make it run.

there is still the problem with "BIOS CRC protection" at hardware level, which blocks G1 bus access (i.e. DIMM/cart in Naomi or GD-drive in Dreamcast),
so fully custom BIOSes would be unable to access DIMM...
but I think this can be avoided using magic 1KB boot chunk from Naomi dev.bios

 

[Ace`]

Is there a list of problems most likely to cause an all red screen? I've got two that do this, haven't had a chance to hook up serial yet to see if they output anything.

 

[1credit]

@nem it was decade+ ago when I've been looking at DIMM 1.02 firmware disassembly, so I can't remember details...

but, in theory, if DIMM<->NAOMI interface have commands like POKE/PEEK to DIMM RAM - it might be possible to upload some our code there and patch DIMM firmware in RAM to make it run.

there is still the problem with "BIOS CRC protection" at hardware level, which blocks G1 bus access (i.e. DIMM/cart in Naomi or GD-drive in Dreamcast),
so fully custom BIOSes would be unable to access DIMM...
but I think this can be avoided using magic 1KB boot chunk from Naomi

Yeh would
Be cool to utilize all them dimms with a flash boot