How to disable checksum

[Jlnhlsegafan]

[Jlnhlsegafan]

Bump

[kingraph]

Did you change the values to 4E71 4E71 4E71? 

[Jlnhlsegafan]

Yes.

Edited November 30, 2017 by Jlnhlsegafan

[kingraph]

Well, if it didn't work, that's all I could think of. 

 

Best to retrace your steps and see where it failed.  Not sure how you replaced the Sabres with Sonic without using NOSE, that's quite a challenge, so perhaps you missed something there.  Without knowing WHAT you did, nobody will be able to help you.

[Jlnhlsegafan]

[Jlnhlsegafan]

This rom hack is doomed.

[Jlnhlsegafan]

19 minutes ago, kingraph said:

Well, if it didn't work, that's all I could think of. 

 

Best to retrace your steps and see where it failed.  Not sure how you replaced the Sabres with Sonic without using NOSE, that's quite a challenge, so perhaps you missed something there.  Without knowing WHAT you did, nobody will be able to help you.

NOSE doesn't work- EVEN IF I use Wine.

[jer_33]

I think troubleshooting NOSE is definitely the better alternative. Making these simple hacks in NOSE is the way to go.

[smozoma]

@Jlnhlsegafan, my suggestion, if you want to get into modding the game, is to just go out and buy a cheap windows laptop from a used computer store or on a local buy-and-sell website (craigslist, kijiji, etc..).

My guess is that you just went into the ROM and replaced the names and hit delete if the old name was too long, or inserted extra letters if the old name was too short? That is unlikely to work. If your new team data is longer or shorter than the original, it will break the game because it will shift everything. It's not like a MS Word document that is read in order, instead the code references exact locations in the ROM, so moving the code breaks it. Your ROM looks like it is a few bytes shorter than the original.

 

You also need to update the the 'name length value' when you change the names. I see that these have not been updated, so the game would crash when trying to read the player names.

Here is how you do the names:

Before each name, the bytes are for example 000C. That is '12' in decimal. That means the name is 10 letters long (+2, because the length value 000C is also included). Only even values are allowed for the length value, so if a name is a odd number length (9, 11...) you add a byte of "00" after the last letter in the name. This is a little hard to explain without examples... I really suggest just getting a cheap laptop, you'll have more fun.

[CoachMac]

11 minutes ago, smozoma said:

@Jlnhlsegafan, my suggestion, if you want to get into modding the game, is to just go out and buy a cheap windows laptop from a used computer store or on a local buy-and-sell website (craigslist, kijiji, etc..).

Yes.

[Jlnhlsegafan]

How... do I troubleshoot?

[Jlnhlsegafan]

7 hours ago, smozoma said:

@Jlnhlsegafan, my suggestion, if you want to get into modding the game, is to just go out and buy a cheap windows laptop from a used computer store or on a local buy-and-sell website (craigslist, kijiji, etc..).

OK.

[segathon]

Good luck with the edits!

[Brutus]

I'd like everyone to imagine this conversation with Royalmenow subbed in for JLnhlsegafan & then try to imagine not jumping into oncoming traffic next chance you get.

[smozoma]

Just want to add a new way to disable the checksum using only 2 bytes (so it's easier to turn into a game genie code...)

at offset 0690, change the value 4E9B to 6004. 

This tells the CPU to skip to the next instruction 4 bytes away, which continues loading the game.

Or as a game genie code:

ATDA-AA6T

[Drezz]

I'm confused. It doesn't really disable it though, right? Yours just skips it, where the other version physically nops it out.

Does it still cause problems if you try to modify anything? 

 

[smozoma]

1 hour ago, Drezz said:

I'm confused. It doesn't really disable it though, right? Yours just skips it, where the other version physically nops it out.

Does it still cause problems if you try to modify anything? 

 

It disables it from being run. The reason I came up with it is for game genie codes, because (as far as I know anyway) if you were to add a game genie code to NHL95 before starting the game, it would trigger a failed checksum. With this change, you can disable the checksum with a single game genie code.

Added the game genie code now in my previous comment... I didn't expect this to get any attention before I could test it out

It shouldn't cause any problems. It basically does the same thing as the NOP version, gets the CPU to the instruction immediately after the original "JSR $001A72C0" instruction without executing the code at $001A72C0. 6004 is BRA #$04, it just moves the CPU ahead 4 bytes (rather than NOPping those 4 bytes)

[Drezz]

That makes total sense. I figured you would have taken all of that into account, seeing as you're the resident expert on figuring out opcodes. I just didn't understand it... and now I do!