Originally Posted by Schoenfeld
One more time: The ACA500 $f0 ROM is switched off by the Blizzard card anyway. What's happening is that the Blizzard ROM crashes, because it does not like something in the A500. There is nothing that an adapter can do about the underlying computer, and there is nothing that an adapter can do about the software in a ROM that it doesn't have control over.
The Blizzard 1230-IV ROM is written for the A1200. I currently have no idea where exactly it fails, but it does, and debugging that would mean a lot of time that I'm not willing to invest. You're free to do so, as removing the SIMM from the Blizzard lets you boot the system, creating a basis for debugging.
If you think about redesigning the whole ACA500, what do you think of an external device for the side expansion slot?
This could save all power problems with an external PSU. No need to open the computer for those who are afraid of that. Room for hard drive or any type of connector (USB, Indivision ECS, etc).