I have been spending the last week to get the I2C port running on pixhawk 1, fmu-v2. This is because I need to use Teraranger One sensor, but I also tried to use it for PX4FLOW module. All tests failed.
I tried to start the drivers from the NSH terminal, but it never passes the I2C initialization phase, and, hence, does not able to communicate with the bus. This is for both PX4FLOW and TeraRanger one.
i have been trying this on the latest stable PX4 firmware 1.5.3.