Hi @JulianOes thanks for the reply. It’s a really strange situation because seems that there are two firmware (both ArduPilot and PX4) at the same time. I’m trying to implement Hardware in the loop with Matlab and if I read my pc COM port after the firmware upload I read COM3 (associated to PX4) and if I disconnect and reconnect the pixracer (without doing firmware upload or something else) my COM port changes in COM5 (associated to ArduPilot). I’ve the the same problem described here for firmware uploading via QGC.
