Experimenting with #JiffyDOS on my #Ultimate64 - it seems to be pretty hit-or-miss. The webpage had a note recommending what seems to be CIA timing settings:
> Can I utilize JiffyDOS on the Ultimate II?
>
> Yes. Customers have noted that settings PH1=140 and PH2=80 work well.
I don’t see any way of finding nor tuning these settings, though. Have I misunderstood something?
#c64 #c64ultimate #c64u
Responding to myself:
Looks like this is one of the fixes in firmware version 3.14d. (https://ultimate64.com/Firmware). Looks like that one doesn’t include the KERNAL and stuff which comes prepackaged in the official FW. But then there is hope.
Responding to myself responding to myself:
I borrowed the KERNAL, Basic, and Char ROMs from a VICE installation, after which the updated #Ultimate64 booted up as expected. I can’t say for sure whether all issues are gone, but Mayhem in Monsterland, which would never load successfully with #JiffyDOS earlier on this machine started up like nothing; and Gunship, which would inevitably crash at an arbitrary point in loading, has come right up into flight mode. Awesome!
Mikael Hansson