Hi Frank,
AFAIK, Lua only runs in boards with 2Mb of flash size.
If you want to test your code, maybe you could check out the SITL environment. You can run a simulated vehicle and command it without any hardware:
https://ardupilot.org/dev/docs/sitl-simulator-software-in-the-loop.html
I am not sure how to use Lua Scripts there, but I guess it is possible and more complete than a board without a receiver or radio. You can also connect the mission planner in the simulated vehicle.