Hacking Hex edit DS VC emulator config?

[awefour44]

Suppose I would like to install and run a stock NDS virtual console title, without injecting a new rom or altering the assets in any way EXCEPT for the emulator’s brightness and screen size parameters. I realize that I could unpack the title, edit the JSON parameters and repack it, but then it’ll be runnable under CFW only. As an alternative, could these emulator configuration values be altered directly somewhere in the title’s binary *.app files via a hex edit? Thanks for any insight here!

 

[godreborn]

I believe the app files are encrypted using the title.tik, so you can't modify them directly. you can modify them after installation though. afaik, they're no longer encrypted then, but they still need the ticket to run. there's a thread with modified ds screen stuff (maybe another for brightness). that was as easy as just replacing the files. one of the places where nintendo really fucked up it'd seem is that files are only encrypted on the outside (i.e. the nand being encrypted but nand content not being or games being encrypted, but decrypted when placed on the hdd, so if you break through the main encryption, you can change, alter anything with ease).

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btw, I believe you can decrypt the app files on the pc with cdecrypt, just need the ticket which you can get from the title id site. however, it might be an issue with ds cuz when I looked on there to find the title id of my ds games, there were no tickets for ds games, at least none that I searched for.

 

[awefour44]

I believe the app files are encrypted using the title.tik, so you can't modify them directly. you can modify them after installation though. afaik, they're no longer encrypted then, but they still need the ticket to run. there's a thread with modified ds screen stuff (maybe another for brightness). that was as easy as just replacing the files. one of the places where nintendo really fucked up it'd seem is that files are only encrypted on the outside (i.e. the nand being encrypted but nand content not being or games being encrypted, but decrypted when placed on the hdd, so if you break through the main encryption, you can change, alter anything with ease.

This sounds promising, and if I understand correctly it means the brightness/screen edits can even be made to a legitimately installed (direct from the eshop) NDS game by modifying or overwriting the installed data on the USB, post install? I’ll do some further research but if there’s a homebrew tool you could point me to that’d be much appreciated, thanks!

btw, I believe you can decrypt the app files on the pc with cdecrypt, just need the ticket which you can get from the title id site. however, it might be an issue with ds cuz when I looked on there to find the title id of my ds games, there were no tickets for ds games, at least none that I searched for.

This sounds like the usual approach (decrypt, edit, re-encrypt) which also is used for injections etc., but the disadvantage as I understand it is the resulting re-encrypted title can only be launched from the CFW, whereas the original stock title can launch from normal firmware (after haxchi has been turned on, which must be done every time but is quick)

 

[godreborn]

I don't think they're encrypted while on the system, only during installation:

I have the config files on my system. I'm using cbhc, so I can't say definitely that they'll work without cfw, but I believe that they will considering.

 

[awefour44]

Thanks— I have no doubt that they’re decrypted after installation, but that leads me to ask how to make the edit post-install? Do I just use an FTP tool to edit the JSON file in place on the USB (or NAND depending)? Or is there software that will let me view and edit my USB’s Wii U formatted filesystem on a PC?

 

[godreborn]

It's easiest just to use ftp. That's what I did to get full screen. I only had 3 or 4 ds games. If you have a lot of games, it might be possible to use robocopy, which is part of Windows. Use dumpster or loadiine to mass install with robocopy. The same files can be used for any ds game.

 

[awefour44]

It's easiest just to use ftp. That's what I did to get full screen. I only had 3 or 4 ds games. If you have a lot of games, it might be possible to use robocopy, which is part of Windows. Use dumpster or loadiine to mass install with robocopy. The same files can be used for any ds game.

Thank you, I’ve not played around with FTP but this seems to be a good reason to try it. I appreciate the advice, thanks again!