Docs I read and sources I check say that $9000.6 controls mirroring. However I'm having difficulty getting the games to work right.
When I do $9000.6 set = vertical
Daiku no Gen San 2 - works
Spartan X 2 - works
Kaiketsu Yanchamaru 3 - does not work
And when I do it the other way around ($9000.6 set = horizontal), it fixes Kaiketsu Yanchamaru 3, but breaks the other two.
After examining the games' behavior... it occurred to me that the games only seem to write to $9000 on startup, and they never change mirroring modes after initially setting them. To test that theory, I took out mapper controlled mirroring and just set the mirroring bit in the games' headers accordingly, and they all work great!
Does $9000 really control mirroring for this mapper? Or is it hardwired on the cart? If it's mapper controlled, is there any way to get all 3 games working without a game specific hack?
When I do $9000.6 set = vertical
Daiku no Gen San 2 - works
Spartan X 2 - works
Kaiketsu Yanchamaru 3 - does not work
And when I do it the other way around ($9000.6 set = horizontal), it fixes Kaiketsu Yanchamaru 3, but breaks the other two.
After examining the games' behavior... it occurred to me that the games only seem to write to $9000 on startup, and they never change mirroring modes after initially setting them. To test that theory, I took out mapper controlled mirroring and just set the mirroring bit in the games' headers accordingly, and they all work great!
Does $9000 really control mirroring for this mapper? Or is it hardwired on the cart? If it's mapper controlled, is there any way to get all 3 games working without a game specific hack?