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Anyone knows how to rip games from multicarts?

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brightentayle:
Okay, at that point, I may quote Cheetahmen's PM considering hacking VT02/03 multicarts. I hope he doesn't get angry on me for leaking such valuable stuff  :rolleyes:  (that's a lame gag, actually, of course he wouldn't). Joke or not, this might be interesting for you guys.

Quote: Before each game name, there's 8 hex values.

The second one determines mirroring. (0 = horizontal, 1 = vertical)
The third one selects the general area that the PRG data is located. (Anywhere between 0 and F, where each holds 200000 hex values)
The fourth does the same for CHR data.
The fifth and sixth ones locate where the PRG data is ranging from 00 to FF. (e.g. PRG data located at 80000 hex = 40)
The eighth one determines the size of the PRG data. (0 = 512k, 1 = 256k, 2 = 128k, 3 = 64k, 4 = 32k and 5 = 16k)
The ninth value determine the location CHR data. (e.g. 1 = 4000 and C = 30000)
The tenth value determines the size of the CHR data (0 = 256k, 1 = 128k, 2 = 64k, 3 = 32k and 6 or E = 8k)
The eleventh value also determines the location by 40000 hex. (e.g. 1 = 40000 to 7FFFF)[/quote]

The "value numbering" may be a bit off, but it's mainly true.

So, as far as I understood from his words, each OneBus ROM file consists maximum of 16 megs of memory. And so it's split to what I'd like to call "pages". Every page holds around 20000 bytes (yes, not the same number with one zero!) and contains the so-called-by-me "subpages". Roughly, the amount of pages and subpages ranges from 00 to FF.

Well, you can open Cheetah's 210-in-1 multicart and look for, let's say, Super Mario Bros. 3. It's easy, actually: you just find its' entry in the menu, check the pre-title values (in our case, it's gonna be the PRG location) and then off you go to find the ROM itself.

In my case...


* I can find a string inside that ROM which reads "SUPER MARIO BROS. 3". The sequence of bytes before the title is, naturally, 00 44 00 01 01 10 A7 86.

* After a wee bit of calculating, I figured out that 20000*44 (all in hex, again, all in hex!) naturally equals 880000, which is basically the page we need to find the game's PRG.

* Long trail of zeroes and we see the PRG data at 880100. Which means that the fourth byte (which reads 01) naturally adds 100 to the offset. 880000+100=880100.

* ???

* PROFIT!!!

Pretty lame info as for now, but I guess this may be enough for the start, cos' I'm yet to figure everything else out. :)

As for Caltron, I dunno thow to deal with that thing yet, although I suggest you may actually use the separate ROM of Magic Carpet 1001 as a reference, despite one single landmark won't help much...

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