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Hey, a fellow user on Sonic Retro suggested that I post this here.

Quote

Since I'm currently working on some Master System stuff and I've wanted to try and advance my C programming abilities for a while now, I've made a program to fix the Master System's checksum as the BIOS won't run the ROM otherwise, making it cumbersome for ROM hacking. Just drag a file and drop it, or include it in your batch scripts.

Post any bugs you have here.

MSChecksumFixer.zip (26 KB)

Hmm, we've avoided making that for years to avoid people polluting romsets with "fixed" roms (e.g. for SG-1000 and Japanese games), and it's a two-byte manual fix if you want to do it yourself. However, we are in an age of 8-bit romhacks by less technical people who may find this helps them.

Yeah, the fixes for the Japanese ROMs wasn't my intention, more so that the checksum wouldn't have to be altered with every subsequent build with any code alteration, something I found to be a nuisance when working on homebrew for it.

WLA DX emits correct checksums. Any devcart with a loader (Everdrive) doesn't need the checksum.

Huh, fair enough. I don't use WLA for assembling Z80 myself, and I can't say I knew about the current devcart omitting the checksum. Nevertheless, it's here if people want to use it, I guess. :A

Dandaman955 wrote

Huh, fair enough. I don't use WLA for assembling Z80 myself, and I can't say I knew about the current devcart omitting the checksum. Nevertheless, it's here if people want to use it, I guess. :A

Hey Daniel,

I needed this to check the checksum of some ROM dumps I found in compilations, and I've removed the writing support to make it into a checker which can run under Linux.

I'd like to make those changes public, but I wonder under which license your work was. Under which license would this work be?

I don't think he's going to see your message, but I happen to be his friend on Facebook so I tried to give him a heads up. What happens now is beyond my control, I'm afraid.

Tom wrote

I don't think he's going to see your message, but I happen to be his friend on Facebook so I tried to give him a heads up. What happens now is beyond my control, I'm afraid.

Appreciated, thanks!

I came back to edit my post with a follow-up, but you were faster than me :P

Anyway, to my surprise, he already replied on Facebook, saying that he's going to look at your post tomorrow, so expect something to happen.

I'm glad I could help.

Hey, you're going to have to excuse me because I haven't really been keeping up with programming in the past year, and I'm not particularly familiar with licenses. Feel free to do what you want with the code, the source is on GitHub.

Dandaman955 wrote

Hey, you're going to have to excuse me because I haven't really been keeping up with programming in the past year, and I'm not particularly familiar with licenses. Feel free to do what you want with the code, the source is on GitHub.

Much appreciated. I've uploaded the new version to:
https://github.com/hadess/smssum
and gave it a free/libre license so any changes to it get shared.

Thanks for this useful tool.

Author	Message
Dandaman955 Joined: 26 Jul 2016 Posts: 4	Master System Checksum Fixer Posted: Wed Apr 19, 2017 8:46 pm
Dandaman955 Joined: 26 Jul 2016 Posts: 4	Hey, a fellow user on Sonic Retro suggested that I post this here. Quote Since I'm currently working on some Master System stuff and I've wanted to try and advance my C programming abilities for a while now, I've made a program to fix the Master System's checksum as the BIOS won't run the ROM otherwise, making it cumbersome for ROM hacking. Just drag a file and drop it, or include it in your batch scripts. Post any bugs you have here. MSChecksumFixer.zip (26 KB)

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14741 Location: London	Posted: Wed Apr 19, 2017 9:25 pm
	Hmm, we've avoided making that for years to avoid people polluting romsets with "fixed" roms (e.g. for SG-1000 and Japanese games), and it's a two-byte manual fix if you want to do it yourself. However, we are in an age of 8-bit romhacks by less technical people who may find this helps them.

Dandaman955 Joined: 26 Jul 2016 Posts: 4	Posted: Wed Apr 19, 2017 10:25 pm
Dandaman955 Joined: 26 Jul 2016 Posts: 4	Yeah, the fixes for the Japanese ROMs wasn't my intention, more so that the checksum wouldn't have to be altered with every subsequent build with any code alteration, something I found to be a nuisance when working on homebrew for it.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14741 Location: London	Posted: Thu Apr 20, 2017 6:56 am
	WLA DX emits correct checksums. Any devcart with a loader (Everdrive) doesn't need the checksum.

Dandaman955 Joined: 26 Jul 2016 Posts: 4	Posted: Thu Apr 20, 2017 7:33 pm
Dandaman955 Joined: 26 Jul 2016 Posts: 4	Huh, fair enough. I don't use WLA for assembling Z80 myself, and I can't say I knew about the current devcart omitting the checksum. Nevertheless, it's here if people want to use it, I guess. :A

hadessuk Joined: 26 Jun 2017 Posts: 7	Posted: Sun Jul 28, 2019 1:45 am
hadessuk Joined: 26 Jun 2017 Posts: 7	Dandaman955 wrote Huh, fair enough. I don't use WLA for assembling Z80 myself, and I can't say I knew about the current devcart omitting the checksum. Nevertheless, it's here if people want to use it, I guess. :A Hey Daniel, I needed this to check the checksum of some ROM dumps I found in compilations, and I've removed the writing support to make it into a checker which can run under Linux. I'd like to make those changes public, but I wonder under which license your work was. Under which license would this work be?

Tom Joined: 16 May 2002 Posts: 1356 Location: italy	Posted: Wed Jul 31, 2019 12:26 am
Tom Joined: 16 May 2002 Posts: 1356 Location: italy	I don't think he's going to see your message, but I happen to be his friend on Facebook so I tried to give him a heads up. What happens now is beyond my control, I'm afraid.

hadessuk Joined: 26 Jun 2017 Posts: 7	Posted: Wed Jul 31, 2019 12:33 am
hadessuk Joined: 26 Jun 2017 Posts: 7	Tom wrote I don't think he's going to see your message, but I happen to be his friend on Facebook so I tried to give him a heads up. What happens now is beyond my control, I'm afraid. Appreciated, thanks!

Tom Joined: 16 May 2002 Posts: 1356 Location: italy	Posted: Wed Jul 31, 2019 12:52 am
Tom Joined: 16 May 2002 Posts: 1356 Location: italy	I came back to edit my post with a follow-up, but you were faster than me :P Anyway, to my surprise, he already replied on Facebook, saying that he's going to look at your post tomorrow, so expect something to happen. I'm glad I could help.

Dandaman955 Joined: 26 Jul 2016 Posts: 4	Posted: Thu Aug 01, 2019 10:54 pm
Dandaman955 Joined: 26 Jul 2016 Posts: 4	Hey, you're going to have to excuse me because I haven't really been keeping up with programming in the past year, and I'm not particularly familiar with licenses. Feel free to do what you want with the code, the source is on GitHub.

hadessuk Joined: 26 Jun 2017 Posts: 7	Posted: Thu Aug 01, 2019 11:31 pm
hadessuk Joined: 26 Jun 2017 Posts: 7	Dandaman955 wrote Hey, you're going to have to excuse me because I haven't really been keeping up with programming in the past year, and I'm not particularly familiar with licenses. Feel free to do what you want with the code, the source is on GitHub. Much appreciated. I've uploaded the new version to: https://github.com/hadess/smssum and gave it a free/libre license so any changes to it get shared. Thanks for this useful tool.

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