Did you update the ROM files/Cores? AFAIR there were some incompatibilities introduced later on; and there was a time, when it really wouldn’t run on hardware. I can assure you it does run generally, but as the Mega65 is a bit of a moving target there are occasions when it doesn’t. I’m currently not in reach of my Mega65, but I’ll check to make sure.
Thanks, I tried several different combinations of core and kernal rom. Currently on the core dated 23.06.22 with kernal rom 920377. Maybe I'll have to go back a few versions but then other stuff won't work again. Yes you are right the M65 is a moving target atm and once they fix one thing two others become broken. That might just be the case here too.