News: 11 March 2016 - Forum Rules

Author Topic: Dragon Buster (Famicom) - hacking it to use different mapper for PowerPak?  (Read 1739 times)

RetroProf

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So I discovered that Namco's Dragon Buster on Famicom uses an obscure mapper:
https://wiki.nesdev.com/w/index.php/INES_Mapper_095

This mapper is not supported by the powerpak flashcart (which i own and am too cheap to upgrade):
https://www.retrousb.com/product_info.php?products_id=34

I've seen a lot of hacks to upgrade NES games to a different MMC standard. I even "hacked" Don Doko Don 2 using some header utility (it's supposed to use Mapper 48, but you can force it to run under a different mapper - surprisingly without glitches), and the Lupin game which in the Goodnes set had the incorrect mirroring. If anyone wants me to dig up what I did to get Don Doko Don 2 working, let me know - this was years ago.

Anyway...

Is there anything one can do to make Dragon Buster work? Can it be forced to run under an alternative Namco mapper? Can one hack it to run under an MMC mapper, or anything else?
« Last Edit: May 02, 2021, 05:33:15 am by RetroProf »

Pennywise

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Anything's possible through assembly hacking. The idea is to find a similar, but more common mapper and hack the game to run under said mapper. Usually involves changing all the register writes for the CHR and PRG stuff.

RetroProf

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Oooooh, Pennywise. I've been playing some of your fan-translations recently. Nice work. :)

As for a similar mapper, yes, I was hoping to find one that allowed the game to run without crashing. I followed this:
Quote
It is to the ordinary Namco 108 family boards (mapper 206) as TKSROM and TLSROM (mapper 118) is to ordinary MMC3 boards. Instead of having hardwired mirroring like mapper 206, it has CHR A15 directly controlling CIRAM A10, just as CHR A17 controls CIRAM A10 on TxSROM. Only horizontal mirroring and 1-screen mirroring are possible because the Namco 108 lacks the C bit of MMC3. Disch's older notes described an extended and mistaken version of this mapper with a full MMC3, so some emulators may be doing it that way. That extended version is identical to mapper 118, except CHR A15 (bank bit 5) controls CIRAM A10 instead of CHR A17 (bank bit 7).

I can't recall which one it was now... There's a whole bunch of different Namco specific mappers. But I was screwing around editing the iNES header on Dragon Buster and making it try to run under different mappers and one of them loaded the caverns, and you could play it, but the status bar was full of garbled sprites. Which is at least better than it crashing at the start. Then I got bored and stopped experimenting.

Pennywise

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Well, there is no simple solution. You either have to spend the time learning the NES hardware to make the proper hack or spend some money to upgrade your flashcart. If you want to pursue it further, NESDev is a good place to go to.

KingMike

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There's probably a reason Namco made those one-off mappers like that.

As Pennywise said, you'd have to learn the hardware to make it work.
If you really wanted to play that game on hardware, I don't imagine buying a real copy and convertor/clone would be that expensive.
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