While it isn't exactly an OS/2 problem, it is a PS/2 problem.

I'm trying to put an MCA Etherlink card in my PS/2 9595.  When the card is
in the machine the machine will not use the hard drives (SCSI drives), not
even the reference partition.  The same is true in a model 70, I can boot up
a reference floppy, but it doesn't see the ESDI HD.  Take the card out and
both machines work fine, HDs and all.  The card is a 3COM Etherlink MCA
card, card type ID is 6042.  There are several jumpers on the card, but I've
no idea what any of them do.

--- FleetStreet 1.19+