The setup:
Compaq Deskpro 386/20s, late board revision ( has 72 pin simms instead of the ram module, none of the board layout schematics from official documentation match), 2mb RAM, Glitchworks RTC, Promise Floppymax controller modded and running XTIDE on IRQ 15 / port 170h, 512mb Industrial CF, 3.5" 1.44mb floppy.

The problem:
Every startup I get a disk controller error. I can resume and the machine boots fine from the CF card. The on-board IDE should be disabled, but in order to disable it I need to boot using the diagnostic and setup disk. So: if I try to boot from floppy using the XTIDE boot menu, the boot process halts at a blank screen. If I turn off the BIOS on the FloppyMax controller (pretty sure it just cuts the 5v to the PROM), the computer will attempt to boot from floppy and pauses in the same spot. I can boot to setup with the controller removed entirely, where I can update the on-board controller settings and turn off the IDE controller; however as soon as I put the controller card back in, same problem.

Has anyone been in a similar situation?