On Wed, 27 Nov 1996, Rob Pelkey wrote:

> There exists a control panel, "Serial Switch", which turns off the IOP for
> the serial chips for compatibility with older drivers which accessed the
> hardware directly - it sets a location in the PRAM which apparently
> affects how the startup code in ROM sets up the hardware.

Thanks for this information, Rob!  Yes, this might be the trick to make at
least serial ports works.  Also, I was under the impression that the SCSI
DMA chip in the IIfx has a 5380-compatibility mode; I was under the
impression that this was a an Apple ASIC, but Allen might be right that
it's just a different brand of Apple glue around a standard 5380.  (I
haven't seen a IIfx in some time now... at least a couple years.)

I wish I could say I have time to hack on this right now.  Does anybody
have a IIfx that isn't afraid to play with this a bit?