Playing with ROM hacks, anyone tried Extra Mario Bros.?

RetroHacker · Post by **RetroHacker** » Mon Jan 26, 2009 8:06 am

I've been having some fun lately playing with various ROM hacks I've found on the 'net. Super Mario Bros. is a prime target for hacking, and there are some cool ones out there. The best one I've found is "Extra Mario Bros.". It's an amazing hack, expanding the original ROM and changing it to use MMC3. Unfortunately, I just can't seem to get it to work the way I think it ought to. I've tried every dump of SMB I can find, and the game works well with the good dumps - the only problem I can find is that the music in the first stage is wrong.

When the game first starts, the music is a short tune from some other place in the game - then silence. If you die, then when the stage starts over with the new Mario, the music is the correct SMB theme. Then everything is fine - and when you get a Game Over, the music is correct on the next game too.

It's like the code reads from a memory location that wasn't properly initialized - and then once that section gets updated with an event such as Mario getting killed, it gets the proper value loaded into it.

I really like this game, and would like to make it into a cartridge. But I'd love to get the music working first...

Any suggestions on where to look or what's going on here? I've asked over at RomHacking.net, and got a little insight - apparently it works on some other, older emulator. I'm using Nestopia, which is supposedly a pretty accurate emulator - and I intend to put it on a cartridge to play in the real NES. I don't have a socketed MMC3 cart, othewise I'd try it. I've had a tough time finding donor games.

Thanks!

-Ian

NotTheCommonDose · Post by **NotTheCommonDose** » Mon Jan 26, 2009 9:23 am

Can you link to Extra?

Post by **tepples** » Mon Jan 26, 2009 12:16 pm

I've seen some other programs that depend on uninitialized memory behave differently on FCE Ultra, Nestopia, and Nintendulator. Is this the case here?

BMF54123 · Post by **BMF54123** » Mon Jan 26, 2009 2:47 pm

Just FYI, this game does work on a PowerPak with the latest MMC3 mapper, and it does the same weird music thing. I usually just die right away to fix it.

Eightbit Allstar · Post by **Eightbit Allstar** » Mon Jan 26, 2009 3:36 pm

Maybe that weird tune when you start the game was made on purpose? It also appears in another hack made by ATA, called Mario vs. Airman (SMB ROM).

RetroHacker · Post by **RetroHacker** » Tue Jan 27, 2009 9:40 am

Maybe that weird tune when you start the game was made on purpose? It also appears in another hack made by ATA, called Mario vs. Airman (SMB ROM).

Somehow I doubt that this is intentional. I think it's more a case of the same person making the same oversight twice. If he's using an older, less accurate emulator, it may have worked just fine for him, and he never would have noticed.

I'm really interested in digging into it and trying to find the problem and fix it, but I don't know enough about the NES yet to attempt such a thing. I'm still in the 'reading and researching' phase of learning NES assembler.

-Ian

Eightbit Allstar · Post by **Eightbit Allstar** » Sat Jul 18, 2009 11:27 am

Sorry to revive this old topic, but did anyone look up, which mapper board this hack needs? I don't know if TLROM or TSROM works.