640KB
So you have the `C000` segment enabled to RAM for UMBs using the on-board SPLD? If you disable that segment does that change anything?
~~And still the same behavior with the garbage/hardware reset I assume?~~ Any chance you have a POST code test card?
The fact that it doesn't boot at all (the first time) is fascinating, and not what I would have expected. It would be interesting to see exactly where in the...
If you hit enter, does it come back?
Okay, well that proves the video reset register works, so that's something that makes sense. That points back to the very beginning of the boot process, because it's doing exactly...
I'd think the first thing would be to figure out why the video doesn't disable immediately on power on, since that's pretty simple and obviously not happening. Somehow there's some...