Is it possible to change the built-in game on Sega Master Systems?

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johhnnyD14

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I've seen a few discussion threads about this topic but I have never gotten a definite answer, nor am I willing to risk doing it myself.

Has anyone even attempted this before?
 
cdamm

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is it even worth the time to do so?
 
Westcb

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Great example on how not to use the tech support forums... Asking about something that you admit you will not do.
 
Xian Xi

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BustedStr8 may know. I remember him doing Fix-it-Felix built in games on Genny systems.
 
Apocalypse

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johhnnyD14 said:
I've seen a few discussion threads about this topic but I have never gotten a definite answer, nor am I willing to risk doing it myself.

Has anyone even attempted this before?
Click to expand...
Yes you can. It's quite easy if the game is less than 32kb as you don't need a mapper.
I've made a BIOS with Great Tennis that can also play Japanese card games (they don't contain the "Sega" text at a specific address so they don't pass the OG BIOS check on US/EUR consoles).
For Mark III cartridge games you need an adapter as pinout is different. Easiest option is to use the expansion port on Master Systems 1 as it matches the pinout of Mark III cartridges (no need to swap lines, etc.).

Link to the thread (in French sorry):
http://www.sega-board.fr/viewtopic.php?t=4042&postdays=0&postorder=asc&start=30
 
chinitosoccer

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The Master System Super Compact made by Tectoy came with either Sonic or Alex Kidd In Miracle World as built-in games, I have seen people mod their MSSC to change between those 2, I don't know if is possible to put other game appart from those.
 
bustedstr8

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Xian Xi said:
BustedStr8 may know. I remember him doing Fix-it-Felix built in games on Genny systems.
Click to expand...

johhnnyD14 said:
Link? That sounds pretty interesting
Click to expand...



Heh...that damn thing. I only did it because I ran out of nice clamshell cases.
I didn't do a write up on it, it was just a sale thread.

I think you could change the game if you inserted the game code at the right address after the bios code and burned a new eprom.

Like Apocalypse said it would have to be a small game since the direct addressing of the SMS is only 32KB. A larger game could be done but it would get messy fast as you would need another eprom, a Sega mapper (from an Afterburner pcb) and also some additional logic to handle /CE of those chips.
 
J

johhnnyD14

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bustedstr8 said:
Heh...that damn thing. I only did it because I ran out of nice clamshell cases.
I didn't do a write up on it, it was just a sale thread.

I think you could change the game if you inserted the game code at the right address after the bios code and burned a new eprom.

Like Apocalypse said it would have to be a small game since the direct addressing of the SMS is only 32KB. A larger game could be done but it would get messy fast as you would need another eprom, a Sega mapper (from an Afterburner pcb) and also some additional logic to handle /CE of those chips.
Click to expand...

What games are less than 32KB?
 
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