Dusted off my m4 nano, flashed the 1919 hills and ran the sim.
Didnt tried the navigation stuff, just some flying in acro..
A suggestion: I flashed it into an all setup nano quad, so with props etc.
Not a problem obviously, running the hill disabled the motor outputs...
But.. I escapped the sim after I was done with it and didnt pay attention to my throttle or other switched and the nano jumped up full throttle, pulled the microusb and stopped in the curtains

Suggestion: set a variable to disable the motoroutput and when the sim is used allow only a reset of that variable after a reboot..
Now it was a nano, but with something bigger it might run into serious problems..
(didnt scan through the code, maybe you already have something in place and I was unlucky)
Well done,
Cheers,
Menno