I'm having difficulties getting anything to work out of my i2c port. I talked to tech at 3d robotics and did a bunch of tests, we were unable to figure out the failure. I cannot get anything working from this connection on the board. Everything else works fine, my airspeed, external MAG, LED all do not work. The GPS works but not the MAG. I'm running latest firmware with mission planner. I checked voltage from the port and am getting correct 5v and 3.3v from the wires but for some reason I am unable to use any external device. I've tried several different cables.Anyone have any suggestions? I'm at the point of buying a new pixhawk to solve this problem.