Our current boards use the BMP280. Try this code for this.
For the unknown message, this is the GPS telling you that it is receiving data on the serial port, but it doesn’t recognize it, so it spits out “unknown msg”
Doublecheck that you have disabled the console on the serial port. If this is disabled, you can try and disable echo on the serial port
stty -F /dev/ttyACM0 -echo
Peter --OzzMaker.com --