Please note, this is for the Erle. I was simply stating that in my usual dealings with Pixhawk I can connect to Mission Planner via the microUSB where as with Erle I have not been able to do so. (follow up question here, but is the microUSB only for power in the Raspberry Pi 3 or can I use it to connect to MP?)
My original issue restated differently:
When connected to Erle via Mission Planner through a mavlink connection, I changed the serial port (Serial1_Protocol) in the advanced parameters in MP thus "turning off" the serial port I was using to connect the Erle to MP. I am now "locked out" of Mission Planner. Is there another method of connecting Erle to Mission Planner or changing the param file within Erle? If not the only thing I can think to do is reflash the card.