Dumping Knuckles in Sonic 2 and Sonic 3 & Knuckles from Sonic Mega Collection Plus

The thing is up til yesterday I didn't even know how to dump the Sonic games from my Sonic Mega Collection Plus PS2 disc until I found this chap's thread on racketboy.com:
http://www.racketboy.com/forum/viewtopic.php?f=52&t=30647

And suddenly I had dumped Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic the Hedgehog 3, Sonic & Knuckles and Ristar through pcsx2 and HxD which I'm now playing happily without quirks in Genesis Plus GX through Retroarch with shaders for an authentic look and a genuine Sega Genesis controller

There were however two games that I couldn't dump:

Knuckles the Echidna in Sonic the Hedgehog 2
http://sonic.wikia.com/wiki/Knuckles_the_Echidna_in_Sonic_the_Hedgehog_2

Sonic the Hedgehog 3 & Knuckles
http://sonic.wikia.com/wiki/Sonic_the_Hedgehog_3_&_Knuckles

For some reason the outcome is always the same, it ends up being Sonic & Knuckles.

From what I understand there were some lock-on technology involved enable to play these versions.
Sonic & Knuckles + Sonic the Hedgehog 2 for Knuckles the Echidna in Sonic the Hedgehog 2 and Sonic & Knuckles + Sonic the Hedgehog 3 for Sonic the Hedgehog 3 & Knuckles.

However being a compilation and all I thought that they had made custom/fused ROMs or something.

Now what I would like to know is whether or not there is a way to dump these two gems properly or if I just have to deal with it and play them through the compilation.

Thanks in advance!

 

The way it works on actual hardware is that you insert the Sonic & Knuckles cart into your Sega Mega Drive then insert the Sonic 2 on top of the S&K cart.
If successful Sonic 2 will start and Knuckles will be playable, if the Sonic 2 cart doesn't get detected properly you get the NO WAY message.
I don't know if the Mega Collection emulator loads both. Any reason why you just don't get the ROMs that are already dumped by other people or you just trying to learn something new here?

 

Downloading is cheating, anyone can do it and it takes the fun out of everything.
I take pride in accomplish these tasks and in return I get satisfaction but yeah also to learn new stuff basically.

The reason I wanted to this is because:
1. I don't own the Sonic games and Ristar for Sega Genesis only the Mega Collection Plus disc for PS2
2. There is several annoyances playing the Mega Collection Plus on PS2 (Sound effects in the first Sonic the Hedgehog would sometimes be delayed, the music volume was incorrect in some games, and the screen resolution differs from the Mega Drive originals) + you're stuck with a PlayStation 2 controller and that's not how these games are meant to be played.

The only game I actually own for the Genesis is Castlevania Bloodlines which I dumped years ago.

So I figured there's gotta be a way to get the games out of there and play it in a proper Sega Genesis emulator much like Ocarina of Time Master Quest can be extracted from the GameCube disc and then be played in Project64.

Turned out it was possible and that made me feel proud of myself because dumping games in this manor is not something I'm used to.

And that's the road I'm on right now. But 5 games dumped out of 7 is not bad at all.

You are probably right, the emulator these games run on must load both games somehow together.
But again, being a compilation and all I thought they fused it to one ROM or something.

So I guess I have to stick to the compilation for these two specific games.

 

Fair enough.
You could actually get the ROM of Sonic 3 & Knuckles and compare it to Sonic & Knuckles you extracted from the Mega Collection DVD,
It would be interesting to see if S3 & K is just the two ROMs joined in a specific way. This is what you would be looking for in the hex editor, where one starts and where other one finishes. Note this is just a theory, it could be more complicated than this..

 

So there is actual ROMs of Knuckles in Sonic 2 and Sonic 3 & Knuckles? Never saw that coming, I mean how?

That would mean that they somehow took the Sonic & Knuckles ROM and sewed it on using a hex editor or something to Sonic 2 and Sonic 3 enable to create these versions.

I have to look into this, I'm not ready to give up just yet.

But it's funny though, if there already is made ROMs of these two why didn't they just use them in the compilation?
That makes you wonder, is the fused Knuckles in Sonic 2 and Sonic 3 & Knuckles ROMs made by someone else?

 

Holy s*** I did it, I actually did it.

By taking the hex from Sonic & Knuckles, paste it to a new hex sheet and then take the hex from Sonic the Hedgehog 3 and paste it under the Sonic & Knuckles hex I successfully created Sonic 3 & Knuckles and it booted!!!!!

However the fusion of Sonic & Knuckles and Sonic the Hedgehog 2 wasn't successful as it wouldn't boot so there have to be something else that has to be done, but I'm working on it, hell yeah.

This is why I'm into this, the pure satisfaction of achieving a task.

EDIT:

I have made some progress regarding fusing Sonic & Knuckles and Sonic The Hedgehog 2.

The size of my fused file is 3072kb which is 2048kb for Sonic & Knuckles being a 16-megabit cartridge and 1024kb for Sonic The Hedgehog 2 being a 8-megabit cartridge.

Technically and theoretically it should have booted just like Sonic 3 & Knuckles did but it don't.

So I decided, for research only to get Knuckles in Sonic 2 and to my surprise it had a size of 3328kb.

I opened up my fused file and Knuckles in Sonic 2 in HxD and compared them and they were almost identical.

But my fused file stopped at 002FFFF0 as compared to Knuckles in Sonic 2 which stopped at 0033FFF0
So there were extra data from 00300000 to 0033FFF0 which weren't present in my file.

If I copied this extra data and pasted it into my file under 002FFFF0 it booted!

What I need to figure out is to where this extra data comes from then I'll be able to get my own file working.

 

I've successfully dumped Sonic 3 & Knuckles with a retrode 2.

 

OK, well I wish I could too but I have to rely on what I own.
I haven't yet figured out where the extra data comes from but I'm getting there, albeit slowly.

6 out of 7 games dumped is not bad at all.

This is real fun though and I'm enjoying every part of it.

 

The guys in the Sonic ROM hacking community know exactly how this works. I never got into it personally, but I would search/ask around SonicRetro.org if you're looking for an explaination.

If you just want the ROMs joined, use this utility: http://info.sonicretro.org/Sonic_HackingWiz_Pro#Sonic_.26_Knuckles_Lock-On_ROM_Creator

 

Thanks but I have now successfully created my own working copies of Knuckles in Sonic 2 and Sonic 3 and Knuckles.
Sonic 3 & Knuckles was easy, just join Sonic & Knuckles with Sonic The Hedgehog 3 and violá a perfect 4096kb dump.

Knuckles in Sonic 2 were a bit trickier and involved some extra data besides Sonic & Knuckles and Sonic The Hedgehog 2.

What I had to do were to start Knuckles in Sonic 2 on pcsx2 and then start digging in HxD.

I knew what the extra data would look like so eventually I found it, copied it and it were a perfect match.
I joined Sonic & Knuckles with Sonic The Hedgehog 2 and then the extra data which gave me a perfect 3328kb dump of Knuckles in Sonic 2 and all through honest work.

 

Good honest work and some help Nice job

 

Thanks guys!

I would also like to say that I tried this with Mega Man Anniversary Collection just for fun, you know if Sonic Mega Collection Plus contained dumpable games so maybe Mega Man did to.

I loaded up HxD and opened up a copy of my Mega Man NES ROM just to get a feel of what I would be looking for later and took some key notes.

Fired up pcsx2 and Mega Man in the Anniversary Collection, then in HxD I started to search using my key notes and yeah I sure found them.

My Mega Man NES ROM ended with MEGAMAN and the one in the collection ended with ROCKMAN for some reason.
Anyway I took the data, slapped on a NES header and assembled it to a .nes file but to my surprise it didn't boot at all just a nice white screen in puNES.

Later when I compared the files I saw huge differences, CAPCOM must have altered the original ROM.

But did I learned something, hell yeah.

At least I can enjoy all the Sonic games and Ristar properly now.

THE END!!!

 

Capcom absolutely changed some stuff around on the collection. It had weird slowdown issues where such shouldnt exist.

Overall the quality of the collections were not good. They were altered slightly to be run natively on the PS2 (and gamecube? i know X collection was multiplat) which led to issues. I doubt they will run in an emulator unless you use a PS2 or PCSX2

 

ROMs can be used for purposes that involve no emulation what so ever. They contain graphics and sound assets.
I don't think how those Mega Man collections work has been deeply analyzed, though the most obvious signs point to being altered PS1 ports.

 

Yeah I know, and there's also weird input lag in Mega Man 8 which is noticeable in the jump/slide part in Frost Man's stage.
Johnny vs. Mega Man 8 covers it pretty good.

Yeah that's probably true but it would have been cool if it actually booted.

 

This is how it functions. S3 and SK are different games, but two parts of a larger game. On hardware SK identifies by header what's locked on and responds in kind. Back in the day (1998ish) we used to use dos to merge them into one file very similar to how you did it in a hex editor. However sonic 2 is different. The SK cart has an additional ROM on the cart that acts like a patch, patching Knuckles into sonic 2. So you need SK, S2, and this additional patch ROM to create a sonic 2 with knuckles

 

OK, so that extra data that was present and I didn't know what it was were actually some sort of patch ROM?

That would explain why I didn't find it in the Sonic & Knuckles hex after I dumped it. Fortunately for me the patch ROM as you describe it was present and used in Sonic Mega Collection Plus which made it possible to fuse the Knuckles in Sonic 2 dump.

Thanks for the info!

 

Maybe it ended with "ROCKMAN" because ROCKMAN is the name of the game in Japan... (lol)

Jokes aside, not all of those repacks are emulated. A lot are actually recompiled from source and run natively on the game system they're at. Like the PS2 Darkstalkers Collection.