Yes, not so easy it would seem. Just been having a look at xroar's source: In dragon.c there's a flag 'unexpanded_dragon32' that when cleared, causes a Dragon to get D64 style decoding for PIA0.bluearcus wrote:Unfortunately this doesn't seem to work...
I can also confirm that the flag only appears to be set if a Dragon is specified with no more than 32K.
Easy enough to mod purely for testing the OS9 boot issue, (make the decode depend on 'is_dragon64' or 'have_acia' instead?) but a more permanent change might need some careful checking to unpick the decode logic.
(Edit: I see you're a step ahead already!)
Also a cautionary note, hopefully I'm being over-cautious: Writing PIAs with bogus values as is happening here might not be very healthy. One thing that could happen is an input line could end up as an output. I've often wondered how bad it would be if say the keyboard inputs were set as outputs such that pressing keys resulted in shorted outputs. Outputs are usually designed to survive some abuse but not too much. It's not something I'd like to try to see what happens, though as I say, I'm probably being over-cautious.