megarom flash cartridge with 2MB Konami 5 mapper

By gregg

Supporter (4)

gregg's picture

21-03-2023, 07:44


I am looking for a cartridge that would allow me to run digital edition of Dim X game. I don't have any flash megarom cartridge yet. So far I have panasonic fs-a1 with 512MB ram and self-built ide/fdd controller (
I received this game in 2 MB rom file and instruction to run it on megaflashrom scc + sd with this command line:
opfxsd game.rom / k5 / u
Megaflashrom scc+sd is hard to find and has features I don't need, so I was looking for other options. Looking at this command line I need Konami 5 mapper ( k5 flag in command line) but the rom file is 2MB, but I think max size for Konami 5 mapper is 512kB, right?
Looking at this page: , Konami 5 mapper uses 4 kB pages, with segments chosen with 6 bits. That would give us 2^6 * 8kB = 512 kB. Does it mean Megaflashrom scc+sd uses some "unofficial" Konami 5 mapper that uses 2 more bits (normally unused) to choose 4 times more possible segments giving 2MB in total?
If that's true, then what other flash cartridge would do the same? So far I considered:

1. - It is open source and simple and I even already have empty pcb, but version 1.0 has 512 kB flash. Version 3.0 has 2MB, but I it is not open source, so I can't build it myself. I also did not find it available to buy.
2. Carnivore2 - It has much more flash, but would it work the same as Megaflashrom scc+sd for 2MB rom image and Konami 5 mapper? I also don't need most of its functionality.
3. Some DIY - I saw schematics for ascii/Konami mappers based on 74 logic ICs, but I think I would have to modify them a bit to support 2MB. Still it should be doable.
4. Upgrade my internal ram to 4MB and use e.g. sofa run to patch game to use ram instead.

Any recommendations? Would any of those solutions work for me?


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By gdx

Enlighted (6214)

gdx's picture

21-03-2023, 10:04

You can use that.

By gregg

Supporter (4)

gregg's picture

22-03-2023, 04:01

Thanks! I did not know about this cartridge.