The C16 / Plus4 cannot be switched between PAL and NTSC. You'd need different MOS chips inside for that.
Is it currently running in NTSC mode?
I also noticed some freezing in some games.
"MAC, I" or "Mad Mamba" (all packed from 1988 CST, if you enter LIST).
Maybe that's because of the NTSC mode you mentioned?
By the way, I don't know any NTSC only games. So PAL Mode would be preferred.
If you have questions about the C16, I had one as a kid for eight years. I also have a real one standing here. Don't hesitate to ask me!
As for jumping to the machine language editor while keeping runstop pressed during reset, this is not so important but would be a nice addition.
You could use it to make a memory dump (not so important anymore as alls software is preserved) or to enter a cheat code and then go back into the game.
For Example Aadvark:https://www.consoledatabase.com/cheats/ ... /aardvark/
(It's not working right now because memory is empty when entering the Monitor.)
PS: By the way there is FPGATED V1.1 available and release notes in 1.01 mentions some reset problems have been fixed.
Documents of MISTer say V1.0 is used right now? All in all release notes seem not to be very interesting though. So I don't know if its worth the work to switch: https://hackaday.io/project/11460-fpgated
Two beer or not two beer? - Shakesbeer.