Net50 bus arbitration

Has anyone ever successfully got the bus arbitration working? I have a Net50 system with external bus master PCI9054. It’s sort of semi-working. Sometimes accessing local memory (e.g. SDRAM, FLASH) from the PCI9054 can cause crash on Net50 and then a hardware reset is required to return to normal operation. If you can share your experience on this that will be very helpful to me. Cheers. Minlin