| User | Post |
Tony Hedstrom
Posts: 2/2 |
Glad I could help. Don't know what I was thinking when I typed 60 as the original value instead of 66.
Incase you're interested, all Genesis Game Genie "Master Codes" are really just checksum bypass codes. So for Tony La Russa, the master code would be:
0FFA98:4E71 = RH7A-86Y2
Tony.
EDIT: Making checksum bypass ROM hacks/codes aren't too difficult, so if you have any other games with a similar problem, let me know and I'll either show you where to hack the ROM, or I'll explain how to do it yourself. |
ktulu22
Posts: 6/6 |
B frickin EAUTIFUL - Nice work man. The value at 000ffa98 was actually 66 instead of 60 but after changing the values to 4e71 it works perfect. Muchos gracias my friend. Now on to disecting this mofo for player attributes and what not. Anybody have any experience at all hacking this game? Thanks again man. Really appreciate it. |
Tony Hedstrom
Posts: 1/2 |
It's the checksum that's causing your problems. Here's how to hack the ROM to bypass the checksum...
Open up your La Russa ROM with a hex editor. Scroll down (near the end of the ROM) to this address: $0FFA98. At that address, the value should be 60. Change the 60 to 4E. Next, at address $0FFA99, the value should be 02. Change the 02 to 71. Save your changes and the game should bypass the checksum. I tried it and it worked fine for me.
In short, this is what we just did... you changed the 6002 instruction at $0FFA98 to a 4E71 instruction. 6002 is a branch instruction, and 4E71 is a NOP (No Operation) instruction.
Once you hack that into the ROM, you will be able to make as many changes to the ROM as you want.
Tony.
P.S. Let me know if you have any problems.
|
ktulu22
Posts: 5/6 |
My mistake |
Luigi-San
Posts: 406/736 |
Posting Rom Links=Bad
But I'll let you off 'cuz it just gives you a 404, anyway. |
ktulu22
Posts: 4/6 |
Good idea - but still no luck. Tried it several times but the game still will not load. Even changing a simple 01 to a 00 and an 00 to an 01 causes the game to crash. I'm getting desperate here. Here is the link to a place where you can download the rom (zipped as a zip file) if you want to mess with it yourself: La Russa Baseball
Again, any help is greatly appreciated. Thanks |
Heian-794
Posts: 721/896 |
I've hacked many baseball games (all for NES and SNES) and have never seen one that won't let you tweak rosters and stats. There's probably a checksum preventing the game from being loaded. Have you tried, say, balancing your stat tweaks (+1 on one number and -1 on another) so that the sum is the same? See if the game runs then. |
ktulu22
Posts: 3/6 |
Thanks for the help guys. I still have not been able to have any luck. The rom is already in binary form so we are good there. If you change any piece of hex (roster or otherwise) the game still crashes upon loading. It could be a checksum issue. I'm going to mess around with it some more today. Again, any suggestions would be greatly appreciated. Thanks again. |
Lenophis
Posts: 484/830 |
Originally posted by Kefka
I couldn't imagine there being a checksum on the rosters... but could there be??? This would seem to be a possibility. And I am not a Genesis hacker, so I would not know how to find a way to switch the checksum off.
EDIT: then again, there might be some sort of checksum for the entire game.
That's entirely possible, however, there's also another culprit that could be at work. The rom isn't in binary format, or at least it might not be. Genesis roms, when dumped, are dumped in such a way that they aren't in standard binary when done so, it's some crazy "interleaving" that makes it pretty much unreadable, etc etc etc and whathaveyou. I suggest you search google for some SMD->BIN utilities, and try again. |
Kefka
Posts: 3204/3392 |
I couldn't imagine there being a checksum on the rosters... but could there be??? This would seem to be a possibility. And I am not a Genesis hacker, so I would not know how to find a way to switch the checksum off.
EDIT: then again, there might be some sort of checksum for the entire game. |
ktulu22
Posts: 1/6 |
Hey fellas - Excellent forum you got here. I've done some light rom hacking before but nothing major. One of my all time favorite games is Tony La Russa Baseball for Sega Genesis. The rosters are ancient so I tried to mess around with hacking it a bit. I open the rom in the hex editor (hexecute) fine but when I edit any single piece of text and then save the game, the game then won't load in the emulator. The screen just stays black. I can see ACSII text cleary in the hex editor so I don't think it's a compression issue. But when I change a single letter of any player's name (or any single hex value) the rom will not load. The few other Genesis Roms I tried did not have this problem. Anybody ever try hacking this game or does anybody have any ideas that could help me out? Would be much appreciated. |
hukka
