@tonyvd,
The 4000 is still how I bought it over a year ago software-wise. I don't have the orginal install media or idefix/CacheCDFS. Now I did try to boot with an emer. disk into OS 3.9, but when it tried to mount CD0 the same thing happened (HD light and Cd-ROM light stuck on, "insert disk" message for the Cd-ROM). I checked the emergency disk and it was using CacheCDFS, too. Hmmm.
@Matt H,
I played with some CacheCDFS settings and no go.
@Thomas,
Ironically enough, CacheCDFS complains about the change interrupts option and deselects it. SCSI-direct by itself had no effect. It also complained about the change interrupts with SCSI-direct off as well.
@Nickman,
I thought a special cable was required that supported cable select. Gave it a go anyway, all combinations, and that just resulted in the insert boot disk screen after a very long delay on boot. So I have got to go with the master/slave jumper settings.
@zipper,
I gave that a try, too, mounting CD0 manually after the 4000 booted. Same result.