I found that the FMUv2 question is related to 1MB flash as described in this link:
https://docs.px4.io/master/en/flight_controller/silicon_errata.html
Here’s another link of some relevance:
https://docs.px4.io/master/en/config/firmware.html#bootloader
It’s discussed here with a possible solution for FMUv2 multi rotors at the end of the thread.
I was able to use the solution referenced above to successfully fly a Holybro Kakute F7 in jMAVSim in simulation in hardware (SIH) mode using this command on a Mac:
./Tools/jmavsim_run.sh -q -d /dev/tty.usbmodem01 -b 921600 -r 250 -o
I created the kakute f7 px4 file using a .cmake file where I included the module “sih”. It was not necessary to remove the two fixed wing modules noted in the discussion because they were not present in the default kakute f7 .cmake file. I then custom loaded it via QGroundControl.
I haven’t found anything to indicate that SIH is available with gazebo or AirSim. But a discussion thread indicated that at one point it may have been used with FlightGear.
I’m not going to be using the SP EXTREME H7, so no worries there.