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Old 07-28-2018, 09:25 AM   #1
dv639
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Default Berzerk not working on real hardware

I was wishing I could play this homebrew on my Everdrive, but even after trying to fix the header and recalculating checksum the game still does not boot. I am greeted with a black empty screen.
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Old 07-31-2018, 02:27 PM   #2
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This doesn't tell us much, what platform? NES?


EDIT: I'm going to assume Genesis. So, since it's homebrew, I doubt that even though there's a checksum, that the game does a check for it. What exactly are you changing in the header, as there are vectors in the table that are essential for the game to function (notably H and V blank)? Also, have you tried running it on a modern emulator? A lot of homebrew roms were only tested on emulators that at the time were not up to snuff in the accuracy department so something that would work fine on say, gens, would break on real hardware.


Finally, later Genesis models had crude copy protection that would do a check for the string SEGA somewhere in the ROM, so games would need to conform to that.
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Old 08-01-2018, 02:48 AM   #3
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Addendum: If you'd like, I suppose I could fire up a debugger and see if the game conforms to the copy protection, that's up to you. In theory, the code needed to make it run on real hardware could be patched in.
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Old 08-01-2018, 09:37 PM   #4
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Sorry for not offering much information, I made this post late in the night and didn't even give much details, that's why I am really thankful for your response, you are a helpful person.
And yes, I am trying to run it on the Genesis, mine is one of the earliest models which didn't even have TMSS yet, so I don't think that's the issue.
In the header of the rom I was trying copying information contained in the header of other roms and then recalculating checksum before trying to fire it up on the console.
I had forgotten that homebrews might not run on the actual hardware, which is such a pitty, I enjoy Berzerk a lot, but the only console I have that runs it is the Atari 2600 with that weird diagonal shooting angle which isn't 45 degrees as it is in the Arcade.
Maybe I just screwed up on the H and V Blank portion of the header.
That's what I will look into if I can understand it.
Thanks again for the response, you gave me one more bullet to try and shoot the issue.
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Old 08-01-2018, 11:43 PM   #5
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Well, it works on blast-em, so I think it's hardware worthy. Are you sure there's no TMSS on that genesis? You should break the TMSS routine on a commercial ROM and see if it bitches. Perhaps Sonic and Knuckles as it doesn't run a checksum routine.
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Old 08-02-2018, 05:20 PM   #6
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I believe mine does not have TMSS because when I fire up my physical cartridge of Street Fighter 2 Turbo the TMSS message isn't shown, and also I can run any non-TMSS compatible game such as: Osomatsu-kun Hachamecha Gekijou, Super Daisenryaku, After Burner II (J).
My Genesis also runs some chinese bootlegs that have a number of games and a menu for choosing them instead of resetting the cartridge, those do not run on my friend's Genesis Model 3 (his model is Master System compatible but has TMSS because the message is shown before many games including my copy of SF2 turbo).
I didn't knew about the Blast-em emulator, I really liked to know about it.
So I believe that the issue should be about bad rom header since it runs on the very accurate blast-em.
I'll be experimenting more with that once I have more time.
Maybe there's a way to work out what Blast-em is auto-detecting with the absence of information on the header to then try and apply those settings permanently on the rom file.
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Old 08-02-2018, 06:53 PM   #7
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At this point, I'm out of ideas. I think the next course of action is hitting up a genesis development forum and seeing if they can reverse engineer what is wrong. Whatever it is, it's doing something the genesis doesn't like that isn't being properly emulated on modern emulators.
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Old 09-28-2018, 08:40 AM   #8
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Today I had time to look into this issue further. Turns out I was using a rom that in no way would run on either Blast Em or my console. It ran on other emulators. I found another version of the ROM that indeed ran on my Mega Drive, even though GenSuite told me the checksum was wrong it ran with both fixed and "wrong" checksum. I just wish I could afford the physical release, it's so beautiful the job they did with the box and cartridge and Berzerk is one of my alltime favorites.
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