Hi again. My further efforts to get Fantasy Zone to run on the System 16B with the 171-5358 romboard have yielded some progress... however it's far from perfect. And I think it will never work without further patches to the program roms. I'll explain why after this photo.
This is the best I got on the 171-5358 ROM board
Memory mapping. It is quite different between System 16 games, and how their ROM boards are constructed. The 171-5358 ROM board is made with the same layout as the System 16A, that is: All chips up to 64K, 3 program rom pairs, 4 OBJ rom pairs, 5 sound roms (the first limited to 32K and contains the Z80 program), and 3 screen ROMs, one for each of the bit planes.
These slots are separated by some memory gaps, and without any further arrangement that is 2Mbit. What happens when I tried to arrange the ROMs in that ROM board, is that I can fit 64KB of program rom in the first chip, however the 3rd piece goes to the next chip which is placed in memory after 2Mbit. As a result there's missing program data (i.e.: Tile maps, sprite definitions, etc.), or rather, the program data is unreachable, reason why when running the memory test, of the 3 program ICs tested, 2 pass and one fail. The first stage must have all the stage data between the 1st and 2nd 32K chunks, but other stages such as the first one that appears on the title screen, don't render correctly:
Title screen with corrupt tiles and sprites
I can probably dig into hacking the program and spread it as it was originally intended but I don't think I have enough time/motivation to go that deep, considering the other work I'm involved with. In any case I just wanted to leave this report here in case either I come back to it, or someone wants to pick it up.
Thanks to everyone who has helped so far.
