[ska]

This is naive. There are tons of firmware changes that will render hardware unusable until the board is re-flashed (which you may not be able to do at that point), and even without moving parts the capability to damage components. Simple example, often firmware is the only thing that will stop your hardware from cooking itself if it is capable of doing so. Or if you mess with battery management you could conceivably get a fire. Or you mess with power distribution and send the wrong voltages, parts are fried. Or, etc. etc.