Dear friend thanks for the explanation and the links, already downloaded and then give a studied, very interesting.
But in my case is only changing the hex-checking, changing this value will cause the checksum verification but normal, but will not crash the rom, unfortunately I have no further information as prints, because I'm at work right now.
KingMike Friend, I've done this procedure did not work, decoded characters and 6:08 manually downloaded tool here and see the site, but failed.
The strange thing is that after decoding the code it points to a particular address is the same address as rom The Punisher (Genesis) which I translated and changed the Checksum, I did another test with the rom Street Fighter II (Genesis) and the same goes Offset .
As said before I believe strongly that the following default address for all games, but the code is changed to be different.
Unfortunately I have no further information at home only.
Then I'll post the prints to better understanding.
Err... KingMike's method does work. I think you might have misunderstood him.
First, this guide explains how to make "Master Codes". http://www.angelfire.com/games2/codehut/ImprovedMasterCodes.txt
These are required for Genesis / Mega Drive games that have extra protection that basically don't work if the game has been edited. To get round this problem, we simple "disable" the checksum, which is what the "Master Code" does. Once they are disabled, you can edit the rom as much as you like and fix the checksum. As a bonus, the game will start up quicker.
Luckily for us, there is a "Master Code" already made for "Road Rash" here: http://www.angelfire.com/games2/codehut/RoadRashGG.txt
In this case, the code is: RH9T-R60T
Using the "Game Genie Code Converter" (http://www.romhacking.net/utilities/23/
), we can get hex code of what is being changed. The result should be this: 07FFD0 : 4E71
I'm not much of an expect on how Genesis / Mega Drive codes work, but I can tell you it is a rom offset and it adding a "do nothing" command. Simple open the rom in a hex editor and go to the "offset": 07FFD0
Replace the values "66 02" with "4E 71".
Now you can make any changes you like. Don't forget to fix the checksum using this: http://www.romhacking.net/utilities/342/
EDIT: Just a screenshot of some of the text edited, to show the above method works: