@tubetime I wonder why a similar situation didn't cause problems in PC land when going from 8088 to 286 bus (and again from 286 to 386)? 8-bit ISA works (mostly) fine on newer machines. I wonder if this is a port-mapped I/O accommodation?

I remember hearing- emphasis on _only hearing_- the 286 has some _slight_ incompatibilities when talking to 8-bit devices with an I/O port at an odd address. But most cards in practice didn't run into this.