Help with checksum fix

Zadezl · 2013-02-10 16:04:43

I'm just a ROMhacking fan and I want to do something for the mobile users in this forum. There are a lot of pokemon hacks that have a problem with the checksum, and the mobile users ( include me ) can't play on our devices. And I know this one can fix it but I don't know how to use. Can any body show me how to use this? Please!

Sorry for my bad english, I'm really bad at writting skill :(

Munchulax · 2013-02-10 21:53:02

Instructions for Windows XP through Windows 8:

Download the Windows RGBDS files from here
Put the unzipped RGBDS files and the ROM file in the same folder
Run Command Prompt and navigate to the RGBDS folder using one of the following methods:
handle_list_tag('
[*]Press WinKey + R and type "cmd" into the window that appears and press enter. Then navigate to the folder RGBDS and the ROM are in. To navigate to the folder, type chdir path to folder. For example, if the folder is on your desktop, type:[list=*]
[*]chdir C:\Documents and Settings\(your username)\Desktop\(RGBDS folder) on Windows XP.
chdir C:\Users\(your username)\Desktop\(RGBDS folder) on Windows Vista and above.
You can also just type chdir Desktop\(RGBDS folder) if your Command Prompt defaults to your username's folder on launch.
If you are running Vista or above, you can also hold down SHIFT while right clicking on the RGBDS folder, then click Open Command Window here.
Type rgbfix -v "your ROM name here".gbc (Example: rgbfix -v PKGolden.gbc)
PROFIT - Now your ROM's checksum has been repaired.

I've always preferred image tutorials to video tutorials for some reason.

Last edited by Munchulax (2013-02-10 22:03:18)

tysonrss · 2013-02-11 00:48:25

Oh God, making something so simple to be so complicated for no reason. Ignore the other steps and do this.

Download teh BGB Emulator, load up the rom(assuming this is a gb/c game)and press ESC, this will bring up the debugger. Click File and go to "Fix Checksums". And there you go. Oh and make sure to click "Save as" and overwrite the original rom.

Last edited by tysonrss (2013-02-11 00:51:00)

stag019 · 2013-02-11 01:49:54

That is far to complicated. Ignore tysonrss, he doesn't know what he's talking about. Not only that, but BGB is Windows only anyways.

What you should do, is open up a calculator and a hex editor. Now, read all the bytes from 0x134 to 0x14C, and type them into the calculator, adding them all together. After you add them all, take the last byte value from the result (the last two characters/nybbles) and put that value at 0x14D.

Then, clear that result out of the calculator, and do the same thing again, but using every byte in the rom, except for bytes 0x14E and 0x14F. Then, take the last two bytes (the last four character/nybbles) and place them at 0x14E and 0x14F.

This is quite obviously the easiest way, and the most cross platform way possible.

Zadezl · 2013-02-11 04:09:14

Munchulax wrote:

Instructions for Windows XP through Windows 8:
Download the Windows RGBDS files from here
Put the unzipped RGBDS files and the ROM file in the same folder
Run Command Prompt and navigate to the RGBDS folder using one of the following methods:
handle_list_tag('
[*]Press WinKey R and type "cmd" into the window that appears and press enter. Then navigate to the folder RGBDS and the ROM are in. To navigate to the folder, type chdir path to folder. For example, if the folder is on your desktop, type:[list=*]
[*]chdir C:\Documents and Settings\(your username)\Desktop\(RGBDS folder) on Windows XP.
chdir C:\Users\(your username)\Desktop\(RGBDS folder) on Windows Vista and above.
You can also just type chdir Desktop\(RGBDS folder) if your Command Prompt defaults to your username's folder on launch.
https://dl.dropbox.com/u/4386305/Skeete … tRGBDS.png
[/list][/*]
If you are running Vista or above, you can also hold down SHIFT while right clicking on the RGBDS folder, then click Open Command Window here.https://dl.dropbox.com/u/4386305/Skeetendo/CMDShift.png
', '*')[/*]
Type rgbfix -v "your ROM name here".gbc (Example: rgbfix -v PKGolden.gbc)
https://dl.dropbox.com/u/4386305/Skeete … RGBDS2.png
PROFIT - Now your ROM's checksum has been repaired.
I've always preferred image tutorials to video tutorials for some reason.

I do like you said, but I have a problem

And, thanks all you guy for helping me :)

@jwibagi: A tutorial video would be great

Last edited by Zadezl (2013-02-11 05:16:52)

Munchulax · 2013-02-11 05:03:44

I can't see the picture you posted.

Zadezl · 2013-02-11 05:10:55

Munchulax wrote:

I can't see the picture you posted.

Fixed

Zadezl · 2013-02-11 07:17:35

Actually, I want to be a ROMhacker but I don't know much about asm :p. So using tools now is my best choice but I will learn about asm when I have free time

stag019 · 2013-02-11 07:17:58

thats what they all say

Zadezl · 2013-02-11 08:14:23

I'm still a student in school so learn a asm is hard for me with a little time

stag019 · 2013-02-11 08:58:20

jwibagi wrote:

I've been reading this and according to it, the Global Checksum (0x14E and 0x14F) need not be correct.

True, but it should be, for semantics sake.

But yes, the entire ROM files, not just the header, as that link says.

stag019 · 2013-02-11 09:04:43

jwibagi wrote:

I'm guessing there is an alternative I'm not aware of.

Yes, it's called rgbfix.

Tauwasser · 2013-02-11 15:59:27

Use the checksum function of your favorite hex editor (010 Editor) do a uint8 checksum ignorint 14e to 14f and use the last 16 bit for global checksum. Do the same thing for the header, making sure you have a proper selection before and ignoring the header checksum bytes.

Don't need no magic fix-it-all tool.

cYa,

Tauwasser

IIMarckus · 2013-02-12 04:27:25

Tauwasser wrote:

Use the checksum function of your favorite hex editor (010 Editor) do a uint8 checksum ignorint 14e to 14f and use the last 16 bit for global checksum. Do the same thing for the header, making sure you have a proper selection before and ignoring the header checksum bytes.
Don't need no magic fix-it-all tool.

I’d rather have “rgbfix -v” run automatically from a script than have to manually open a specific hex editor and make sure I select the right range for the checksum every time. Very easy to make a typo and my hex editor doesn’t do checksums anyway.

Munchulax · 2013-02-12 04:38:15

I've found rgbfix the easiest option for me. I just wrote a batch file for my project ROM and I click it when I need to repair the checksum.

stag019 · 2013-02-12 04:40:34

Munchulax wrote:

I've found rgbfix the easiest option for me. I just wrote a batch file for my project ROM and I click it when I need to repair the checksum.

Why would you want to double click a batch file? Obviously, opening up a Windows-only emulator, opening up it's debugger, finding it's checksum fix option (amongst all it's other GUI options), then saving that file is far easier.

Munchulax · 2013-02-12 04:53:02

Eh, I was bored so I just made one. If I already have a command prompt window open (which I do sometimes), I'll do it manually. But if I'm ever hacking on my Linux OS, I'll use your method instead.

I really only use Windows 'cause of the programs my school uses that I have to install, especially since my computer occasionally connects to a SMART Board to teach.

Last edited by Munchulax (2013-02-12 04:54:28)

stag019 · 2013-02-12 04:54:25

Which method is my method? I've already described 3 different methods in 3 different posts in this thread.

Munchulax · 2013-02-12 04:55:12

stag019 wrote:

That is far to complicated. Ignore tysonrss, he doesn't know what he's talking about. Not only that, but BGB is Windows only anyways.
What you should do, is open up a calculator and a hex editor. Now, read all the bytes from 0x134 to 0x14C, and type them into the calculator, adding them all together. After you add them all, take the last byte value from the result (the last two characters/nybbles) and put that value at 0x14D.
Then, clear that result out of the calculator, and do the same thing again, but using every byte in the rom, except for bytes 0x14E and 0x14F. Then, take the last two bytes (the last four character/nybbles) and place them at 0x14E and 0x14F.
This is quite obviously the easiest way, and the most cross platform way possible.

This method.

Last edited by Munchulax (2013-02-12 04:55:28)

stag019 · 2013-02-12 04:57:27

jwibagi wrote:

How would one like myself add the value of every single byte in the ROM?

Besides, rgbfix works great on Linux. And Unix. You just have to compile it yourself, but that's much easier on Linux than Windows.

Munchulax · 2013-02-12 04:59:20

jwibagi wrote:

How would one like myself add the value of every single byte in the ROM?

I could do it...if I had the time. I was kidding :D.

stag019 · 2013-02-12 05:07:29

Munchulax wrote:

jwibagi wrote:
How would one like myself add the value of every single byte in the ROM?
I could do it...if I had the time. I was kidding :D.

Try it.

Let me know when you lose patience.

Munchulax · 2013-02-12 05:11:27

No time right now, I should be doing my English homework right now :P. My patience isn't so good, so I would probably fail after 20 or so values.

stag019 · 2013-02-12 05:12:26

Munchulax wrote:

No time right now, I should be doing my English homework right now :P. My patience isn't so good, so I would probably fail after 20 or so values.

20 values in hex or 20 values in decimal? Because if the latter, then you wouldn't even be able to get the header checksum done. :P

Munchulax · 2013-02-12 05:13:23

Of course hex. :D

Skeetendo

#1 2013-02-10 16:04:43

Help with checksum fix

#2 2013-02-10 21:53:02

Re: Help with checksum fix

#3 2013-02-11 00:48:25

Re: Help with checksum fix

#4 2013-02-11 01:49:54

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#5 2013-02-11 04:09:14

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#6 2013-02-11 05:03:44

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#7 2013-02-11 05:10:55

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#8 2013-02-11 07:17:35

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#9 2013-02-11 07:17:58

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#10 2013-02-11 08:14:23

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#11 2013-02-11 08:58:20

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#12 2013-02-11 09:04:43

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#13 2013-02-11 15:59:27

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#14 2013-02-12 04:27:25

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