Hacking Writing to cartridges?

[Liroku]

This is probably an extremely stupid question, but since we have the ability to read from cartridges has there been any research given to temporarily changing/bridging connections to allow you to write to the chip?

In my mind I am assuming that all games are basically the same internally with basically a different Rom saved to the memory. Am I wrong in assuming this? I haven't popped open a game cart myself, obviously.

 

[Sicklyboy]

https://en.wikipedia.org/wiki/Read-only_memory

Game carts are indeed different internally, and the ROM is called such for a reason.

 

[Snailface]

ROMS are Read-Only Memory which answers the first question.

The second, there are two general types of carts, one with plain ROMS with separate EPROM save chips and a more recent NAND ROM that has a nand partition on the ROM. The ROM partition is still not writable.

 

[Liroku]

I understand why it's rom, but I figured it would all be part of a Nand Rom so they could have non volatile while still allowing write access for save storage and other misc data. I guess it would make more sense to have a second nand/flash for these kinds of things separately. At 1am my question at first thought seemed legitimate..I should probably get some sleep.

 

[how_do_i_do_that]

NAND ROMs are NANDs with a propitiatary hardware lock, aka a "burn once" rom.

Here is an example: http://www.toshiba.co.jp/about/press/2011_04/pr_j2701.htm

If you want to know about what NANDs nintendo uses etc: http://gbatemp.net/threads/wth-slc-nand-nand-saving-ap.356852/

 

[SuperSVGA]

This may be a stupid question but, do you think it would be possible to make rewriteable cards, kinda like the developer CTR-008 cards work? Would the 3DS be able to tell any difference between a writable and non-writable chip (i.e. retail) if they were made exactly the same?

 

[Pleng]

Of course it's possible. The first DS flashcards has built in re-writable memory as far as I remember. And even so, modern flashcards have an SD slot which goes one better and provides removable, rewritable memory

The issue is not getting rewritable code INTO the 3DS, it's actually being able to run the code once it's there. 3DS Games are encrypted and any code you want to run on the device needs to be signed, unless an exploit is found which will enable the running of unsigned code.