nesdev.com

After releasing my two games as free roms, I realized that some emulators will not support the 512kb mapper 2 configuration. I understand this is because the original board only went up to 256kb afaik. Are there any mappers sufficiently similar from the NES heyday that are widely supported in dozens of emulators (like mmc3 is virtually guaranteed due to SMB3 etc. etc.) that I might be able to issue new versions of the games for that would likely have more support in existing emulators?

*edit* It occurred to me that now Mapper 30 has been assigned the above configuration, and presumably this website and its wiki are considered the authority for emulator authors to use for mapper documentation, perhaps all I need to do is change the mapper number to 30 to be likely to be supported by more emulators going forward.

Having looked at the FCEUX source ... why do you say that it didn't support 512 KiB PRG ?

Reasonably recent versions of fceux don't run my games successfully; I had used a special branch bunnyboy gave me, and then later 2.2.3 seems to work.

There was a funny ... intentional bug? in recent but not most-recent versions of FCEUX where Zeromus had explicitly broken how bus conflicts worked on UNROM, during FCEUX version 2.2.2 and 2.2.3(svn rev 2997- rev 3142)

But it's definitely always supported 512 KiB PRG...

There is no reason not to support oversize UNROM, really. You shouldn't change the mapper, your game isn't the problem, the emulator is.

fwiw, i edited the header in your ROM (with HxD: fceux seems to have parental control against editing headers), and it turned out "iNES mapper #30 is not supported at all" for version 2.2.2. Just to be sure, i tried NES 2.0 format too. So changing mapper wouldn't solve the issue anyway. Eventually, i guess 2.2.2 won't be considered reasonably recent anymore.

(deleted the file with the modified header afterwards)

_________________
http://www.frankengraphics.com - personal NES blog

I just tried a mapper 30 ROM in FCEUX SVN, and I didn't get an error message about an unsupported mapper. So FCEUX must have gained support for mapper 30 between 2.2.2 and today.

Would it be enough to recommend FCEUX 2.2.3 (from here)?

Hey, Nesticle runs Owlia BTW.

I noticed PowerPAK default mappers doesn't support oversize UNROM either---I have to use thefox's unofficial powermappers. I am distributing those to users on social media who want to use their PowerPAK, but with what you're saying here I'm wondering if bunnyboy should incorporate those into the mappers he distributes by default.

I've actually tried running Owlia on Nesticle in DOSBOX, myself! So meta... I noticed my cycle timed black bar at the top is a little bit jumpy in nesticle though. Not surprising given how early of an emulator it was I suppose.

2.2.3 Should support oversized UNROM and BNROM games, I've noticed this problem too where the data above a certain threshold would be cut off, so my PCM demos looped way too early (Because Bank $10 was treated as Bank $00 and so on).

Maybe to answer the original question:

MMC3 - UxROM 16k PRG banking can be simulated with 2 x 8k PRG banking. 512k PRG + CHR-RAM was a used configuration (e.g. Mega Man 4/6)
MMC1 - MMC1 has 16k PRG banking, main disadvantage is the serial register interface, 512k PRG + CHR-RAM was used (e.g. Dragon Warrior III/IV)
VRC7 - Like MMC3 but Famicom only and relatively rare, 512k PRG + CHR-RAM was used (Lagrange Point)


As far as FCEUX goes, the oldest version I can find (2.0.0 circa 2008) runs Owlia and also definitely supports 512k BNROM. I think if 2.2.2 had some problem with Owlia it was not about the PRG size, probably some other transient bug.


I would say that an emulator is far more likely to have a 512k-accepting mapper 2 than any mapper 30. You should really only use mapper 30 if you need the flash save capability or CHR-RAM banking. (I would doubt there's any emulator out there that supports mapper 30 but not 512k mapper 2?)

Memblers' Cheapocabra/GTROM (111) has pretty similar capabilities too.