Dumping the DSP1B firmware

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jeffythedragonslayer
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Dumping the DSP1B firmware

Post by jeffythedragonslayer »

I want to reverse engineer Super Mario Kart. I have dumped the ROM with a Retrode and imported it into Mesen-S. Then, I get this message:
This game requries a firmware file for the DSP1B chip.

Filename: dsp1b.rom
Size: 8192 bytes

Would you like to select it now?
This is not one of the files I see in Explorer when I plug the Retrode in. How do I dump it?
lidnariq
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Re: Dumping the DSP1B firmware

Post by lidnariq »

You can't, as far as we know. The existing DSP firmwares were dumped by decapping.
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jeffythedragonslayer
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Re: Dumping the DSP1B firmware

Post by jeffythedragonslayer »

I guess the reason is that those chips have no command that will get them to write all their firmware out, since that is not something the console would ever need to do. It sounds like I need to learn more about decapping; while I think this particular chip has been dumped, is there a TODO list of other chips anywhere? (The PPUs are the big ones I know).
lidnariq
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Re: Dumping the DSP1B firmware

Post by lidnariq »

As far as I know, the only chips in the NES and SNES world that both have a ROM somewhere inside and haven't yet been dumped are the various prerecorded speech chips for the Famicom. One of them has been decapped by Sean Riddle: http://www.seanriddle.com/m50805.html but requires staining to extract the remaining bits; the others are all based on NEC's µPD7755/56.

Someone else may know to the contrary...
Pokun
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Re: Dumping the DSP1B firmware

Post by Pokun »

Decapping requires special lab equipment I think and isn't cheap nor is it easy to do and can easily fail. It also destroys the chip so it is a sacrificial for knowledge, kinda like throwing an eye into Mimer's well.
lidnariq
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Re: Dumping the DSP1B firmware

Post by lidnariq »

It's certainly easier to decap something if you don't care about it working afterwards, but getting working decaps isn't all that much harder.
Pokun
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Re: Dumping the DSP1B firmware

Post by Pokun »

Oh I see, but you do destroy the packaging so I guess the chip's life may be compromised as naked.
creaothceann
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Re: Dumping the DSP1B firmware

Post by creaothceann »

AFAIK proper decapping involves separating the layers as they may be hard to distinguish otherwise.
My current setup:
Super Famicom ("2/1/3" SNS-CPU-GPM-02) → SCART → OSSC → StarTech USB3HDCAP → AmaRecTV 3.10
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jeffythedragonslayer
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Re: Dumping the DSP1B firmware

Post by jeffythedragonslayer »

For the sake of anyone else wanting to RE Super Mario Kart:

https://github.com/Yoshifanatic1/Super- ... isassembly
Pokun
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Re: Dumping the DSP1B firmware

Post by Pokun »

Thanks for sharing your work. A disassembly is always nice to have when you want to check something out.
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jeffythedragonslayer
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Re: Dumping the DSP1B firmware

Post by jeffythedragonslayer »

Oh, Yoshifanatic1 isn't me. I just hadn't noticed this repo before
Pokun
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Re: Dumping the DSP1B firmware

Post by Pokun »

Oh OK thanks anyway.
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