I had a chat with Uto, who created Maluva. He has a M4 himself and says the game works fine there, so we are not able to reproduce this. Here is what he wrote btw. you may want to try both ways, not sure how you've set the content of the game up:
There are two ways to play in M4 though:
1) drop all the files in a folder in the SD, this way I have not tested
2) drop the two .dsk files and run emulated disks (this one I tried)
We also had a look at the USIFAC since we never heard of it before. Seems to be a good thing. From what I read it should work. My point here is that the game is running on real hardware, and if it does that it's more a problem of the device and firmware rather than of the game itself. Since we don't have such a device we are not able to dive deeper anyway. Hope you understand :) Cheers!