GCN Replace the roms in Sonic Mega Collection?

[FreezingIceKirby]

I'm trying a little project here, even though I don't expect to get too far.

Basically, what I'm attempting to do is replace a rom inside Sonic Mega Collection. I made an ISO using a copy that I own, and I even found a tool that allow me to extract everything out of said ISO (and compile it all back again for use in Dolphin or Nintendont). Once extracted, there's a folder listed as "roms", and all the games can be found in there.

Problem is, they're all in .dat files, and from what I've read over many websites and so-forth, .dat files are apparently tricky because they have such a large range of how they're handled. Even though I have no hard evidence of this, I *think* the .dat files here are just compressed files, as I followed this guy's trick ( http://www.racketboy.com/forum/viewtopic.php?f=52&t=30647 ) and was able to successfully extract the roms out of the code and save them as a file (.bin) that the Genesis emulator could play.

Unfortunately... I've no idea how to actually get into these .dat files and save/replace them with something else. None of the tools I've come across can do it, though I wasn't exactly sure what to look for.

So basically put, I think these .dat files are just compressed .bin files, and said .bin files can be played in a Genesis emulator... but I've no idea how to get into the .dat files (extract them?) so I can replace that file with something else (or at least, create a whole new .dat file and just exchange the two), so I'm kinda stuck. I figured I'd try to get some help here, if any of you folks know what to do here.

Anyone have any suggestions?




And, because it'll surely be asked, this is the whole (yet silly) point of why I'm actually trying to do this; I want to replace one of the roms with Rocket Knight Adventures. Yeah, I know, there's no guarantee it'll work if I even somehow find a way to insert it, and I know I can just play the game on a PC or Wii Homebrew emulator... but I love the Wii U Pro Controller, and I don't think the guy who's making GenPlus GX is going to add support for it anytime soon (since he labeled it as "Low Priority"). So, yeah.... the whole ridiculous point of this is to play one game with the Wii U Pro controller, because I want to use that instead of a Wiimote.

(It's one of my favorite games of all times, if that helps excuse why I'm trying something so ridiculous. Also, apparently Rocket Knight Adventures and Sonic the Hedgehog 2 are exactly the same size, so I figured exchanging the two wouldn't actually be too difficult... once i figure out this whole .dat hurdle.)

 

[RevPokemon]

Unless the DAT file is in a format an extractor like Winzip or 7-zip can "read", it is not possible to extract the files out of the game (hence a corrupted file error). Most commercial games won't make it so easy to grab their media. They may encrypt the archive upon compressing it.

Also it would be a lot easier to try to use pro controller on PC

This will help if you want the Wii u controller on PC

Https://gbatemp.net/threads/wii-u-pro-controller-to-pc-program-release.343159/

 

[Sheimi]

The only thing I could think of is to see if you can get the data of the encryption or compressed data of the rom and try to insert it back via ram. Taking the data of a rom in Sonic Mega Collection in it's encrypted/compressed form, writing down the offsets and do the same of the newly inserted rom. Doing that may help you, but I don't know if HxD will allow you to see the encrypted/compressed file. I don't think Dolphin will allow you to save a modified file.

 

[FreezingIceKirby]

Unless the DAT file is in a format an extractor like Winzip or 7-zip can "read", it is not possible to extract the files out of the game (hence a corrupted file error). Most commercial games won't make it so easy to grab their media. They may encrypt the archive upon compressing it.

That's... what I was afraid of. Since all the known unzipping programs I know of didn't do a bit of good (Winzip, Winrar, and 7zip), I'm going to assume my case is hopeless and I should probably give up. Ahh well... it was fun while it lasted.

(Although I learned later that Rocket Knight Adventure's not actually compatible with the emulator in Sonic Mega Collection, so what I was doing was actually even more hopeless than I first thought! That alone also makes this project no longer worth taking on.)

In any case, thanks for the info, and thanks for that link as well!

 

[FreezingIceKirby]

The only thing I could think of is to see if you can get the data of the encryption or compressed data of the rom and try to insert it back via ram. Taking the data of a rom in Sonic Mega Collection in it's encrypted/compressed form, writing down the offsets and do the same of the newly inserted rom. Doing that may help you, but I don't know if HxD will allow you to see the encrypted/compressed file. I don't think Dolphin will allow you to save a modified file.

Thanks for the suggestion! Believe it or not, I actually tried that... well, after finally figuring out I could do that with Hex Editor, anyway (I'm not experienced with that program in the slightest bit). Unfortunately, much to my disappointment, when I replaced the Sonic The Hedgehog 2 ram data with Rocket Knight Adventures, I was greeted with a very pretty... red screen of death. I could still access the return-to-menu screen (Z button), which means it didn't crash the game itself. Also, I did replace the correct data, as I had another Genesis rom that's the exact same size (a rom hack of Sonic 1 that replaces Sonic with Vector the Crocodile), and it worked perfectly... though it was temporarily, of course (as soon as you close out of the game, the ram returns back to the normal Sonic 2 data).

In any case, I found out that while it may be possible in some way... there's no point, as the game I'm wanting to insert is completely incompatible with the emulator in Sonic Mega Collection. Ahh well...

 

[Sliter]

sorry but can I ask wich tool do you use to extranc and compile it all back ? o3o

and btw, if youjsut wnat to play the game on "gamecube", there aren't any megadrive emulator for GC? maybe it work like or better you are looking for ?