I wrote a program that reads the Flytrex data and generates a flight logbook entry. If you send me the dat file I can see if it is something I could work with.
I called DJI today about reading the .dat files.
They said that on the PC ground station, that you need to use the USB connections AND the BTU connection while flying a mission. And install the BTU driver. Then you will be able to use the iOSD Data Viewer and GPS Exporter to read the .dat files. I have not tested their solution yet, but will try later.