Right. I think I was just still in the room when the lights went out. :-) I peek in here pretty rarely, but that probably still puts me in the top N% of visitors.
I was just clarifying that I'm not an insider. I'm just a hobbyist, as noted in the other thread.
I don't think I've ever even seen the screen you're describing, except in captures, as I recall it doesn't run on MacOS.
It does catch my eye that the first field you've entered ends in "2mb"; does this imply a bogus partition table?
Barring any progress, I'd try to get a JTAG probe in place and read/verify the partition table that's being written to the device and pencil-whip it against what you'd expect a 1MB (that's REALLY small!) table to look like. Then I'd get some single-stepping (gross, I know) into the function just before you crash and then try to work backward with what data was written into the partition table that sent you down in flames to start with.
It's painful and there may be no gold at the end of that rainbow, but that's how I would tackle it.
I could be wrong...
