You can read here that current os4 doesn't support the mediator : http://main.aminet.net/hard/drivr/openpci.readme
So os4 drivers can't work. I guess the pci bus and cards are completly handled by elbox' 68k library and drivers. But they have no driver for cgx as used in morphos.
Maybe the mediator sound and network device drivers work in morphos, though.
