Not a Lost Art: Arcade Game ROM Hacking

Coin-operated games and arcades.
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undamned
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Not a Lost Art: Arcade Game ROM Hacking

Post by undamned » September 16th, 2014, 6:29 pm

Sure console ROM hacks are still happening all over the place, but it seems far less common to see arcade ROM hacks beyond the SSFII Rainbow days. I thought it would be nice to have a thread to highlight current ROM hacking efforts. I'll start it off:

Early this year, I had an idea that it would be super cool to have a "training" type mode for Super Street Fighter 2 Turbo that would run on the actual arcade hardware (not emulation/script based). I first contacted Razoola to see if he'd be interested, but at the time he was in the thick of the PC2NEO project. I later ran into a thread on the Shoryuken.com called Hacking the ST ROM. One of the posters in there, jedpossum, seemed to really know a lot so I hit him up with the idea. All I asked for initially was to kill the timer and prevent zero health from ending the round.

I don't know how many hours Jed spent learning how those portion of the game program actually work, but it was impressive to say the least. I watched some of his live debugging streams where he was testing pieces of game code and finding the effects of certain changes and it was very interesting (and quite painstaking). One thing that was unforeseen was that even after modifying the program to not end the round when a character had zero health, there were other things that would supercede that "rule." Bash grabs were one of the things that would break that rule and kill the character. Also the slowdown that occurs when a characters health is depleted was somewhat difficult to eliminate.

While he was pecking away at that stuff, I got thinking that it would also be cool to have Max Super Meter, so he also added that to his potential feature list. What he finally ended up with was even better than what I had envisioned. On the character health, rather than just preventing zero health from ending the round (which he did successfully implement), he made it so it replenishes after a few seconds (like in most training modes you see in console fighters), so you can actually see how much damage your combos are doing. Another thing he added that I hadn't really thought of (and should have) was being able to get back to the character select screen after practicing for a while. Rather than having to re-boot the game entirely or enter/exit the Test menu, Jed added a feature where you simply hold the START button for a few seconds and then you are returned to the character select screen. It's so simple, it's perfect! And the icing on the cake is that the stages are now randomized, so you don't have to keep fighting on the same stage over and over.

If you are wondering how to set this up yourself, you'll need a Super Street Fighter 2 Turbo board, the ROM files for EPROMs 3 & 4 (specific to whatever version you are running: original (if you have a live battery), Phoenix, or Avalaunch/Clean), and the appropriate patch file from Jed for whatever ROM set you have . You patch your ROM files and then burn & replace EPROMs 3 & 4. Here's a demo:

https://www.hasntfiguredouthowtoembedyoutubeproperly.com/watch?v=nsvMFhaQR3M"

-ud
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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by TadCool » September 16th, 2014, 7:31 pm

This is really great, man! :clap:

...now I need this. :shifty:
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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by emphatic » September 16th, 2014, 7:39 pm

Cool stuff!

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by pulstar » September 16th, 2014, 7:51 pm

Awesome. :) Would be an excellent feature (although I'm guessing a pretty extensive hack) to have both the training mode and the normal game available on the same set of eproms. Good work.

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by richmal » September 16th, 2014, 8:12 pm

This is really cool :)
I bet this took a lot of time

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by alamone » September 16th, 2014, 10:10 pm

I have written stage / loop select hacks for Xexex, Tatsujin-Oh, Gradius IV, and Outzone:
http://alamone.net/temp/

The Gradius IV one was a real pain to make because of PowerPC and the MAME debugger doesn't work correctly with mirrored addresses.

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by rjosal » September 16th, 2014, 10:29 pm

Arcade hacks are awesome. I've always wanted to hack San Francisco Rush. For one I want to drive the white car. And then I want to be able to do all the N64 cheats they added like low gravity or night mode (black fog, which is played during attract mode too). And play my own music. Practice modes for STGs are awesome too. It's easy enough to watch the memory of a program running on your computer but I don't know where to start with an arcade pcb.

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by Stompp » September 17th, 2014, 7:16 am

Awesome job :awe: I've been working with software development for almost two decades but this is still black magic to me :(

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by richy13 » September 17th, 2014, 10:20 am

Wow thanks for uploading a video of this :)

The CPS2 development board lets you do the same when in development mode apart from holding start to return to the player select.

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by rancor » September 18th, 2014, 10:51 am

trap15 did arrange modes of Ketsui and Dodonpachi. Managed to get a C&D letter from CAVE.. :lolno:

http://pastebin.com/VrXgLheC"

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by LEGENOARYNINLIA » September 18th, 2014, 11:16 am

I would love a hack for the first Tekken that sets the second camera view as default. I wonder how hard that would be to pull off.

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by alamone » September 25th, 2014, 7:58 pm

I've been informed that my Gradius IV mod is running in game centers in Japan, including Try Tower and Mikado.

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Re: Not a Lost Art: Arcade Game ROM Hacking

Post by rjosal » September 25th, 2014, 8:44 pm

That's awesome! Although I'm not sure why a gamecenter wants a stage/loop select.

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