What I'm curious about, though, is why the MMM works on any 128kb games at all, if Panasonic MSX2+ systems don't allow for this sort of memory assignment? Because there are quite a few games I can play with the MMM that I couldn't without it, like Pumpkin Adventure 3, Bombaman, Akin, and (if and ONLY if the MMM is in the second cartridge slot, NOT the first, for some reason) Lilo. But then there are a bunch I CAN'T play with it, including The Witch's House, the recently released Morning Star, and (I've been told) Pumpkin Adventure 2.
The mapper works completely fine, there’s nothing wrong with it. The problem is non-standard software which asks the mapper "which bank is currently selected here". They’re not supposed to do that because those registers are write-only. Sometimes it works, but in many cases it will give the wrong value.
If the mapper contains logic for read-back, this can make that nonstandard software work on some machines. However on other machines like the WSX, no matter how the mapper responds, it will always return the wrong value, the answer provided by the external mapper is ignored.
Neither the machine nor the mapper is at fault. All the memory can be accessed in its entirety and is fully functional on all machines and with all mappers. The problem really lies with the software.
(I just added this explanation to the wiki btw, hope that helps future readers.)
But then there are a bunch I CAN'T play with it, including The Witch's House, the recently released Morning Star, and (I've been told) Pumpkin Adventure 2.
Would be good if someone made a wiki page with a list of these titles, that the community can expand. Perhaps then some may feel compelled to create patches for these titles to just get rid of the problem at the source. Or maybe NYYRIKKI could adapt his ROM patching AI for this.
That's a really good idea, actually. I've tried a lot of different games, so if you do decide to compile such a list, please let me know and I'll try to give you the information I've gleaned thus far. It's really been about 50/50 at this point.
Does it work if I press Ctrl key at startup?
Normally, pressing the Ctrl key disables the virtual drive function and saves memory.
I tried that already and the game did not boot up. It got to the white screen where you would see the Konami logo, but the Konami logo doesn't show up on the screen. I just get a static white screen.
I also made a list of games that seem to read the memory mapper registers but I can't verify if they work or not when these registers are not readable.
* Bedroom Olympics
* Blue Warrior
* For The Day II (Mirinae Soft)
* Match Maniac (Abyss)
* Many pirated Megaroms
* Pentaro Odyssey - The Revenche (Works but no music)
* Psy-o-Blade
* Sanriku Ouja 0 (M-Kai)
* The Great Giana Sisters (Sunrise)
* Trojka
