Thanks, that seems to solve the problem. I could now move a file to it, warm reboot with all acatune settings, and read the file back out without any corruption.
Jens should hire you to fix his software.
I can now get to try booting from it. Is it possible to change the boot priority of the drive using aca620rd after it has been already been run? Think that it would be most convenient to not have it bootable until all needed boot files has been copied to it.
Edit: I have just tried creating a bootable device and copied a WB 3.1 floppy to it. It seemed to work fine and booting time was obviously very fast. In Sysinfo I see around 5.7MB/s on the drive, so a good deal faster than the standard IDE interface.