@keropi
Both Mediator 1200 & 4000 use the DMA trick. It does mean that if you use the native OS4 mediator support, it limits the cards you can use (10mbit realtek card instead of 100mbit for example. Not that the 100mbit card ever went much faster than 10mbit in a mediator anyway).
However, if you want, you can remove the native drivers for the cards in your mediator and still use Elboxes 68k drivers. They even work with the native Picasso96.