Question: Is it possible to "Untrim" a 3DS game?

[Fugus]

Is it possible to untrim a trimmed 3DS game to have it still match the No-Intro database?

The space saving for trimming them can be huge and there isn't an option for decrypted and trimmed on the Dat-O-Matic. Being able to trim and untrim them would be a decent compromise if it's possible.

[Hiccup]

Yes you can. There's a few tools out there like Crappy Tiny Reader and 3DS ROM Tool. Keep in mind trimmed (or untrimmed) dumps shouldn't be submitted to the database, only unmodified dumps should be. But yeah for ROM collecting purpopses you can store them as trimmed to save space, although they wouldn't match the dat. By default ROM managers zip up the ROMs but still allow you to match the dat, and you get the same space saving from that, since the padding that's being trimmed is just repeated FF bytes.

[Fugus]

Yeah, I was thinking about that but actually trying to use them while compressed is a hassle.

Citra doesn't load them while compressed and while the RetroArch core does, it isn't as updated and can take a while decompressing it to play it to the point when I tried I was wondering if it had crashed.

Thinking of the space savings overall, but that also depends on how often the person wants to revert and audit a set. Really matters for those who actually play them versus just stores them.

Thank you though.

Edit: On rereading this, something I think I messed up communicating. I what I was meaning was that you could "Untrim" the game and it would match the old values. Similar to how if you extract an RVZ back to ISO it will still match the ReDump dats.

[Hiccup]

Edit: On rereading this, something I think I messed up communicating. I what I was meaning was that you could "Untrim" the game and it would match the old values. Similar to how if you extract an RVZ back to ISO it will still match the ReDump dats.

Yeah you can.

[Fugus]

Cool, thank you very much. Much appreciated.

[Fugus]

Further question if you don't mind.

Since you can untrim a rom and have it match the original 100% while also being smaller. Any chance of adding a Decrypted+Trimmed option for the dat files?

I doubt it since then it wouldn't be completely untouched even though it could be reverted losslessly, but figure its worth the ask.

[Hiccup]

I think that's a possibility. As a first step, someone could run a trimming tool on a fullset, then untrim, to see if there are any errors. Would Encrypted+Trimmed also be useful?

[Fugus]

I don't have the full set to test on, I do have a decent amount of the US Set but not enough for anything definitive testing wise. I can try on what I have though if you would like.

As far as an Encrypted+Trimmed version, I didn't even know you could trim an encrypted one but some would probably enjoy it. But overall I am thinking that most who would go through the trouble of trimming are also the ones who would go through the trouble of decrypting.

One thing I still can't figure out is how what to do with the CDN sets, like how to build them into something useful without a modded 3DS and Godmode9.