NES Game Genie patch issue

[Whipon]

Actually, even that's basically a crap shoot, because there's no guarantee that the file addresses shown will actually be banked to a position the code can affect. Generally, I find the address, and set execution/read breaks on the data, and when it hits a point that the code is executing code where the suspect byte fits the compare, then I search for a unique set of bytes in the file that identify only locations where that change may fit. Included in my view is whether the last 3 digits of the code match the last 3 digits of the file address(-0x10 to adjust for header) match one-another.

This is the only truly effective way I know to implement Game Genie codes into a ROM file, without inadvertently changing code you don't want changed. Also note that there are sometimes cases where a particular grouping of assembly code is duplicated across more than 1 bank in the same relative position as the other assembly code is at when loaded, and multiple byte changes will be in your best interest in these cases.

The method I described works perfectly. Its the method I use everytime to hack my codes directly to the rom. And its easier than the method you described. Try it and you'll see how much time it saves you. In the remote case you get more than one result, you just have to use trial an error until you find the correct one. You just have to alter one byte, so its not a big deal.

[ugetab]

Trial and error works well enough too.

It's just that it's a good idea to not leave in unaffected bytes, and the inexactness of the recoding can have undesirable effects on code execution. I've even seen official GG codes with unreported errors, so I play it safer than necessary in most cases.

[Fuego]

Well, I was doing a couple more codes today and I came across one that had three possibilities. I did the trial and error method like Whipon suggested and it worked out well. I think what you do ugetab, is a level or two higher than just changing a couple of bytes, which is what I do. Your's sounds a lot safer, but a lot more involved, and at least to me, more prone to errors due to ignorance.

In any case, I feel a lot better about doing something like that for nes games. Thanks for the input!