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Author Topic: Some help for a newbie (want to alter a rom)  (Read 2490 times)

Artemix

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Some help for a newbie (want to alter a rom)
« on: May 05, 2015, 01:23:50 am »
Hi, I'm new here.

I want to alter a Neo Geo rom, but I don't know where to look honestly, I've got these files:

224-c1
224-c2
224-c3
224-c4
224-m1
224-p1
224-s1
224-v1
224-v2

I've read somewhere that if I use an HEX editor and I find the right place, I can modify the game, at least a slightly.

I know exactly what I want to modify, but even when I open the files with the HEX editor it makes no sense, which I suppose that is fine, and I shouldn't be able to read it, however a "look in this file in that region of code" would be nice so at least I know where to look.

Any help is appreciated!.

Dr. Floppy

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Re: Some help for a newbie (want to alter a rom)
« Reply #1 on: May 05, 2015, 05:06:38 am »
1) What Game?

2) What do you want to do/alter??

freem

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Re: Some help for a newbie (want to alter a rom)
« Reply #2 on: May 05, 2015, 07:31:59 am »
Based on the filenames, it looks to be Twinkle Star Sprites.

The 224-p1 file is probably going to be what you want to edit, as that has the game's main code.
However, you're going to need to byteswap it in order to perform hacks on it, and then re-byteswap it back when you're done.

Artemix

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Re: Some help for a newbie (want to alter a rom)
« Reply #3 on: May 05, 2015, 10:27:21 am »
1) What Game?

2) What do you want to do/alter??

1) Twinkle Star Sprites


2) When you play the versus mode, the game picks a random map from 4 maps, and it excludes the last 2, that are only available when you play the semi final and final in the history mode. I'd like to include these 2 maps in the random pool.

May 05, 2015, 10:28:28 am - (Auto Merged - Double Posts are not allowed before 7 days.)
Based on the filenames, it looks to be Twinkle Star Sprites.

The 224-p1 file is probably going to be what you want to edit, as that has the game's main code.
However, you're going to need to byteswap it in order to perform hacks on it, and then re-byteswap it back when you're done.

You are correct sir!, how the heck did you recognize the game based on those files?  :cookie:

No idea what the byteswap is, any heads up?.

May 05, 2015, 12:20:13 pm - (Auto Merged - Double Posts are not allowed before 7 days.)
Btw, I'm willing to pay someone to do this alteration. I have a fulltime job and I don't really want to spend hundreds of hours looking for one tiny bit of data to change.

Thanks.
« Last Edit: May 05, 2015, 12:20:13 pm by Artemix »

freem

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Re: Some help for a newbie (want to alter a rom)
« Reply #4 on: May 06, 2015, 12:39:31 am »
You are correct sir!, how the heck did you recognize the game based on those files?  :cookie:
Every Neo-Geo game has an ID ("NGH number") used for identification in the BIOS, on memory cards, etc.

No idea what the byteswap is, any heads up?.
Just a simple file manipulation, possible with either ROMWak or with some code by Hans Vahlenkamp (binary), among other tools. (No idea what OS you're on, but if you need to recompile the code for your OS, it's available here.)

2) When you play the versus mode, the game picks a random map from 4 maps, and it excludes the last 2, that are only available when you play the semi final and final in the history mode. I'd like to include these 2 maps in the random pool.

Btw, I'm willing to pay someone to do this alteration. I have a fulltime job and I don't really want to spend hundreds of hours looking for one tiny bit of data to change.

Thanks.

If no one else gets to it before me, I'll take a shot at it.

Artemix

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Re: Some help for a newbie (want to alter a rom)
« Reply #5 on: May 06, 2015, 01:57:01 am »
Every Neo-Geo game has an ID ("NGH number") used for identification in the BIOS, on memory cards, etc.
Just a simple file manipulation, possible with either ROMWak or with some code by Hans Vahlenkamp (binary), among other tools. (No idea what OS you're on, but if you need to recompile the code for your OS, it's available here.)

If no one else gets to it before me, I'll take a shot at it.

Thanks.

May 10, 2015, 12:23:41 am - (Auto Merged - Double Posts are not allowed before 7 days.)
Any news?.
« Last Edit: May 10, 2015, 12:23:41 am by Artemix »