Modding an NDS game cartridge on the 3DS

[ven3u]

Is it possible to mod a game cartridge being used on the 3DS?
Specifically MKDS, i want to edit save data, my .nds file version of the game has it's save data modded, i was curious if you could mod it in the same way, but on a cartridge, and how?

 

[Kwyjor]

Specifically MKDS, i want to edit save data, my .nds file version of the game has it's save data modded, i was curious if you could mod it in the same way, but on a cartridge, and how?

Dump the save data, edit the save data, and then write it back to the cartridge. What else would you expect..?

You can use Checkpoint to access DS cartridge save data, if that's what you're wondering.

 

[ven3u]

Dump the save data, edit the save data, and then write it back to the cartridge. What else would you expect..?

You can use Checkpoint to access DS cartridge save data, if that's what you're wondering.

Is there a guide page for performing all of that?

 

[Kwyjor]

Is there a guide page for performing all of that?

Take a moment and try it for yourself, and if you still can't figure out, search around and see if you can find suitable instructions. If you find instructions that you cannot understand, then you can ask specific questions about what you have difficulty understanding.

Kindly do not jump to "is there a guide" as your first question.

 

[ven3u]

Take a moment and try it for yourself, and if you still can't figure out, search around and see if you can find suitable instructions. If you find instructions that you cannot understand, then you can ask specific questions about what you have difficulty understanding.

Kindly do not jump to "is there a guide" as your first question.

Okay well, I've managed to dump save data, and get to an editor, I just need to rewrite it onto the cartridge now.
I managed to export it via FBI and I've got it on an editor I found on here.

Post automatically merged: Apr 9, 2026

I've got an idea of how to do it, but I ought not to delete the wrong thing obviously, in GM9 on the cartridge directory there is
4 files, ending in .bin, .nds, .sav, and .trim.nds, which should I delete and which should I replace with the new .sav data, and if theres any capability of pasting a file in gm9, you can copy files, delete files, but i see nothing about pasting, and finally, does the name of the .sav data matter? or would that format automatically.
Edit:
I created a backup of my MKDS save in checkpoint, opened that backup file in file explorer, and replaced the .sav of that backup with my edited .sav, and then restored it.

 

[Kwyjor]

I created a backup of my MKDS save in checkpoint, opened that backup file in file explorer, and replaced the .sav of that backup with my edited .sav, and then restored it.

Yes, that's why I said "use Checkpoint" and not "look at the cartridge with godmode9".

 

[k66]

If you have already modified the save files of the NDS ROM on the SD card.
You can use TWiLightMenu++ to sync DS cartridge's save.
(Remember to back up the DS cartridge's save first.)
Enhanced Playing Save from retail NDS Cards with TwiLightMenu++

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