Hardware Homebrew Homebrew game Need help with a custom game cartridge

[TheDuck3000]

I'm making a homebrew game for the 3DS, and want to be able to give some of my friends a custom game cartridge for the game. However, as I am using devkitARM, I can't sign it via nintendo (I don't have a license anyway). For getting this to work, I have the following ideas:

1) Flashcart and injecting my own .3ds file into another title, if that is possible.
2) Flashcart with an exploit that can boot a .3dsx.
3) Custom cartridge hardware that can manipulate the way the 3DS reads and loads games.
EDIT 2: 4) Somehow sign the .3ds file so that it can be run directly off a flashcart?
Any help here would be greatly appreciated!

EDIT: Important to note that they don't have CFW and are not willing to install it.

 

[ClipperDefiance]

I think what you want just isn't going to work. Going by this page, only a few types of flashcart support homebrew and they all require old firmware versions.

 

[Kwyjor]

You'd probably have to rig up something with ntrboot. ntrboot is usually used to install boot9strap, but you can also use it to launch Luma, and there's even a build of Godmode9 that can be run directly via ntrboot (as opposed to being run from the SD card). I'm kind of lost on the specifics, though, and having to use a magnet and key combination each time you want to run the game might be inconvenient.

 

[Technicmaster0]

You may be able to use optio2n 2 but with limitations. It would require some work and the game size would be limited to a part of the save chip of the game (depending on the check sums etc)

 

[TheDuck3000]

You may be able to use optio2n 2 but with limitations. It would require some work and the game size would be limited to a part of the save chip of the game (depending on the check sums etc)

I've never heard of optio2n 2. I looked it up and can't find anything about it. Is there a github page or something you can link here?

EDIT: Just reread it, did you just mispell "option 2"?

Post automatically merged: Aug 5, 2024

I took a look inside one of the game cartridges and found a Macronix IC, but they don’t have any info on the website. Anyone know a place I can find information about the chip? It’s a MX23J series chip.

 

[Technicmaster0]

I've never heard of optio2n 2. I looked it up and can't find anything about it. Is there a github page or something you can link here?

EDIT: Just reread it, did you just mispell "option 2"?

yeah I ment option 2, sorry.

 

[Kwyjor]

I took a look inside one of the game cartridges and found a Macronix IC, but they don’t have any info on the website. Anyone know a place I can find information about the chip? It’s a MX23J series chip.

I'm not sure what you're hoping to find, but in the end, if it was even only a little difficult for someone to make a custom 3DS cartridge, the market would have been completely flooded with bootlegs of official carts by now.

 

[TheDuck3000]

The main thing I’m trying to do with that is to find out how I can directly interface with the flash chip to find out more about how the game is sent over to the 3DS. I’m hoping there is an identical chip under a different name I can read the docs for.

 

[XLuma]

The main thing I’m trying to do with that is to find out how I can directly interface with the flash chip to find out more about how the game is sent over to the 3DS. I’m hoping there is an identical chip under a different name I can read the docs for.

Games are stored on custom Mask ROM/NAND chips. They are read only, meaning you cannot rewrite them to put your own software on there.
3DS Games are signed using RSA, and the private key is only known by Nintendo. You have more chances to win the lottery than cracking that private key. So you also cannot fakesign software at all.

The only hardware solution close to what you want is the Sky3ds, and they went out of business a while ago already. You can sometimes find listings on ebay for the Sky3ds+ (which is the version you would want).

So either they mod their 3ds, or you backport your software to target the DS and you buy a flashcart for that system.

 

[duwen]

The only hardware solution close to what you want is the Sky3ds

Not really. Sky3ds cards could never run homebrew.

 

[TheDuck3000]

Games are stored on custom Mask ROM/NAND chips. They are read only, meaning you cannot rewrite them to put your own software on there.
3DS Games are signed using RSA, and the private key is only known by Nintendo. You have more chances to win the lottery than cracking that private key. So you also cannot fakesign software at all.

The only hardware solution close to what you want is the Sky3ds, and they went out of business a while ago already. You can sometimes find listings on ebay for the Sky3ds+ (which is the version you would want).

So either they mod their 3ds, or you backport your software to target the DS and you buy a flashcart for that system.

Wrong. GM9 is able to overwrite the .3ds file on a game cartridge just fine.

 

[XLuma]

Not really. Sky3ds cards could never run homebrew.

Hence why im saying "closest". His friend's 3ds would still need to be modded to let the sky3ds run unauthorized code

Post automatically merged: Aug 5, 2024

Wrong. GM9 is able to overwrite the .3ds file on a game cartridge just fine.

Source: trust me bro

Gm9 literally only allows to read and dump the content of a cartridge. By design, cartridges are read only.
Don't ask me, just go read the gm9 source code

 

[TheDuck3000]

Hence why im saying "closest". His friend's 3ds would still need to be modded to let the sky3ds run unauthorized code

Post automatically merged: Aug 5, 2024

Source: trust me bro

Gm9 literally only allows to read and dump the content of a cartridge. By design, cartridges are read only.
Don't ask me, just go read the gm9 source code

Mistyped that. Meant the save file. However the reason it can’t write anything other than the save is simply that that area of the chip isn’t write accessible by the cartridge pinout, but if you can directly interface the chip it is possible to edit it because it is a NAND chip.

Post automatically merged: Aug 5, 2024

At least theoretically.

 

[XLuma]

Mistyped that. Meant the save file. However the reason it can’t write anything other than the save is simply that that area of the chip isn’t write accessible by the cartridge pinout, but if you can directly interface the chip it is possible to edit it because it is a NAND chip.

Post automatically merged: Aug 5, 2024

At least theoretically.

the NAND on those cartridges is custom. there are two parts to it: the controller chip, and the memory. the controller will simply refuse to write to any address that is part of the game area. no bypassing this. Game area reads also cannot read the save area.

As for using the save area, retail cartridges will never reply with save data anyway unless when specifically asked for it, and never for code that will be executed anyway...

Your best shot is to convince your friend to softmod their console with a non-permanent method with the *hax methods (browserhax, soundhax...)

 

[TheDuck3000]

Ok, one last question. If I were to put my own unsigned .3ds file on a flashcart, would it run on a modded 3DS?

 

[XLuma]

Ok, one last question. If I were to put my own unsigned .3ds file on a flashcart, would it run on a modded 3DS?

If you use a stargate3ds or a Sky3ds+, probably. I don't think anybody tried this, so its a 50/50.

 

[TheDuck3000]

If you use a stargate3ds or a Sky3ds+, probably. I don't think anybody tried this, so its a 50/50.

Ok thank you

Post automatically merged: Aug 6, 2024

If you use a stargate3ds or a Sky3ds+, probably. I don't think anybody tried this, so its a 50/50.

Do you know any cheap clones? I can't seem to find any.

 

[Kwyjor]

Do you know any cheap clones? I can't seem to find any.

Please think about this for a moment. There are already heaps of bootleg DS games out there. Why wouldn't the market be completely flooded with cheap bootlegs of 3DS games if there was such a thing as a cheap clone?

 

[TheDuck3000]

Please think about this for a moment. There are already heaps of bootleg DS games out there. Why wouldn't the market be completely flooded with cheap bootlegs of 3DS games if there was such a thing as a cheap clone?

I don't know of any good ones (except for a $20 on AliExpress, but thats still a bit too much for me), so I'm asking if anyone else knows of any that I don't. I know that they are really hard to find.

 

[Kwyjor]

You didn't answer my question.

so I'm asking if anyone else knows of any that I don't. I know that they are really hard to find.

Sir, they don't exist.

I don't know of any good ones (except for a $20 on AliExpress, but thats still a bit too much for me)

Please provide a link to what you've found. Odds are it's just a DS flashcart.