ZFx86 - MZ-104 Single board computers

Has anyone used QNX4 on Tri-M Systems MZ-104 single board computers? The
MZ-104 board uses a ZF Micro ZFx86 processor and we are having difficulty
using DMA to transfer from PC/104 I/O to memory. There is a region of
memory that just doesn’t get written during DMA, even though the ZFx86 8237
DMA controller registers indicate that it is addressing the memory region
and the I/O transfer takes place. I have talked to ZF Micro about the
situation and they don’t yet have any suggestions other than the thought
that that QNX might be scribbling over their BIOS extended data area. We
have used many other SBCs and PCs in our systems and have never seen this
kind of behaviour until the ZFx86. I am not really looking for anyone to
provide solutions to this issue because I know I haven’t provided nearly
enough info, so I am just wondering what people’s experiences with the ZFx86
chip have been.