Home › Forums › gShield › grblShield Support › Grbl Controller 3.4.1 /dev/ttyS0
Link Guide
http://zapmaker.org/raspberry-pi/3-alamode-arduino-connect-to-the-pis-gpio/
Candungo,
I would check back with posting a comment on that blog for help. These forums are for the grblShield support. If you can use a terminal like cool term and make the grblShield move your motors then that will verify your gShield is working.
I have never got grbl working with my RPi.
Riley