Homebrew Rewriting a 3DS game in Godmode9?

[Alex4nder001]

Godmode9 is a very powerful tool. It can read all 3ds gamecards, dump the rom and save file, and much more. So I was thinking... is it possible to rewrite the game ROM within Godmode9? I have a few 3ds games, some of which I am bored of. And although an unmodified 3ds does not run unsigned code, it could still prove useful for 3ds hackers, for example for when you need a particular game for an exploit but don't have it. Also, with a game that contains a cart update, would it be possible to replace the update file with one that contains an older firmware version, but is renamed to a higher one?

 

[Asia81]

ROM.
Search definition and you'll have your answer.

 

[The Catboy]

3DS games use a ROM, which is short for "Read-only memory." Which means they can't be rewritten unless you set it to read-write, which is something you can't do without modifying the ROM chip itself.

 

[Asdolo]

Well, an EEPROM is a ROM but it actually is re-writtable, but 3DS carts does not uses such kind of ROM

 

[Jayro]

Well couldn't you technically mount a ROMFS from the SD card, and modify it that way? (I know there's no way to flash a ROM chip unless it's EEPROM or Flash-based.)

 

[Majickhat55]

ROM chips can't be rewritten no so you literally cannot alter the contents of a cartridge, but ROM files themselves can be extracted/explored, edited and rebuilt/saved. If it's not a cartridge like @Jayro said, you can mount the image and edit the RomFS/ExeFS in Godmode9 all you want to. Granted you'd have to have the replacement files on your SD card since there isn't really a program to directly edit RomFS contents in Godmode9 unless you want to change some minor things in a HEX editor. Otherwise, it's smarter to just dump the ROM do whatever, then install it.

As for your other question, obviously the answer is no since you can't write to the cartridge. You can (again) dump the ROM and spoof the required firmware when rebuilding though.

 

[KiiWii]

Riivolution style rom hacking?

 

[Majickhat55]

Riivolution style rom hacking?

That's just game patching, not rewriting the ROM. There are more than a few "on the fly" game patchers for the 3DS (Luma, OnionFS, NTR, SaltySD etc). From his OP I'm getting that he wants to write an edited ROM to a cartridge which is not possible.

 

[InsaneNutter]

Think of 3DS games as a DVD-R, once written to you can't re-write them.

 

[KiiWii]

That's just game patching, not rewriting the ROM. There are more than a few "on the fly" game patchers for the 3DS (Luma, OnionFS, NTR, SaltySD etc). From his OP I'm getting that he wants to write an edited ROM to a cartridge which is not possible.

Ah yes re-reading it looks as though OP wants to put a different game altogether on another random 3DS game cartridge.

Cant be done.

My interpretation was to patch the existing game for mods etc.

I was wrong.

How about for Sky3DS? How about possibility to repurpose godmode9 to write roms to a Sky3DS cart from internal SD card or network, or something? Rather than needing a PC?

I'm hijacking this thread....

 

[Majickhat55]

I mean I guess you could but I imagine the transfer times would be abysmal depending on the read/write speed of your SD card since it has to go through Slot-1 as well. The console doesn't have direct access to that SD card by default. Not to mention it would take up twice the space copying from SD to SD before deletion, and probably just take a million years over FTP since it's not technically transferring to the console, but using it as a conduit of sorts.

Meh, just seems a lot faster to just use a PC/large SD card and edit all your roms then just put them all on the Sky3DS. It can toggle between at least 30 games so I honestly don't see why someone would need what was described above.