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Patching tool update (Patchinator)

Started by Tony H, February 02, 2023, 02:00:28 PM

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Tony H

Making improvements to a Genesis/32x ROM patching tool (Patchinator).

The current version (0.9) is here:

The current tool (shown above) lets you patch Game Genie codes into your Genesis, Mega Drive, or 32x ROMs, and can also fix the checksum if needed.

Still working on the layout (above), but the planned improvements are:

* Can enter 3 codes at the same time now instead of 1.
* Will be able to enter raw codes if you want (ROM address and value).  Could not enter raw codes before.
* Program will let you know if your Game Genie codes or raw ROM addresses are odd numbered.  ROM addresses should be even numbered to work correctly.
* Will have a "Reset/Clear" button which can be handy if you want to patch more codes into your ROM.
* Improved checksum fixing.  Should now have 100% success rate when fixing checksums for Electronic Arts (EA) ROMs.  Will be able to fix most if not all checksums on Capcom ROMs.  EA and Capcom games usually don't use the checksum value in the ROM header (at 0x18E) for their checksum checks.  Most Genesis checksum fixing programs fix checksums by just fixing the checksum value in the ROM header, which often won't work with EA and Capcom games (and others).  Will also have improved checksum fixing on other ROMs. 
* Will have an option to automatically fix the checksum after patching.
* Can create a new ROM if you'd like when you patch your ROM.  This will create a new ROM with "Patched" added to the end of the file name so it's easy to remember which ROM was patched, and will keep your original ROM safe.  You can rename your patched file anything you want, just as long as it's not the same as the original ROM.
The Code Hut:

Game Genie codes and ROM hacking guides

Tony H


Can now add notes for any of the codes you are going to patch into your ROM.  Can type in code descriptions up to 200 characters for each of the 3 codes. You can click a button and it will create a new text file and include the name of the game, as well as the codes and code notes.  The program will automatically enter the name of the ROM you are patching as the name of the new text file, but you can change it to anything you want.  You will also have an option to have it automatically create the new text file after it patches your ROM.

I thought this new feature might be handy to help people remember what they patched into their ROMs.
The Code Hut:

Game Genie codes and ROM hacking guides

Tony H

Currently working on improving the checksum fixing part.  If anyone has any suggestions for games/ROMs that you want included for fixing checksums, let me know.  You can usually tell if a checksum check fails after patching a ROM when the game won't start, and you just get a blank red or black screen.  The program will fix the checksum check on lots of games, but there are probably many games that it still can't fix.  Since there are so many different ways that games do the checksum thing, it's hard to get them all working.

Screenshot shows changes since last time.  This is a Capcom game, and it now shows the ROM address where the checksum routine starts (right above the "Fix checksum" button near the bottom).

Have made these improvements:

* Now shows the size of your ROM, and will limit the highest ROM address you can patch based on that.  This will avoid an error if you try to patch an address that's higher than the size of the ROM.
* It now shows you what type of ROM you have opened.
* The patching part seems to be 100% working now.
* The "Create new ROM" part is working now, and will be adding a feature where it automatically switches from the original ROM you had opened, to the ROM you just patched.  This keeps your original ROM safe, and makes it really easy to continue patching more codes into your ROM.
* The part that displays the ROM addresses for checksum routines is working now.  I will probably add these ROM addresses to the text file that you can create with your codes and code descriptions.  Some people might find that information useful.
* The "Fix checksum" part is working now as well.
* The "Auto-fix checksum" and "Only fix header checksum" options are working.

Again, if anyone has some games/ROMs that you want me to test to see if the program can fix the checksum, let me know.
The Code Hut:

Game Genie codes and ROM hacking guides

Tony H

Finished the update:

Screenshot above shows the final design.

Other improvements since the last post:

* Can now patch ROMs up to 14.6 MB in size.  Demons of Asteborg ROM is the biggest Genesis ROM I know of at 14.6 MB.
* No longer uses a separate dll file.
* If you decide to create a new ROM when patching, it will automatically switch you over to the new ROM that you just named and patched, so you can patch more codes if you want.  This keeps the original ROM that you opened safe.
* Got the text file with the codes and code notes finished (screenshot below).

Screenshot just to show what the text file looks like that the program can create.
The Code Hut:

Game Genie codes and ROM hacking guides