After travelling from my home in NC to the Florida keys, I received a compass calibration error on my first start-up.  I remembered something I saw on line about accessing the compass calibration routine from anywhere within the Go4 app by quickly switching back and forth between P and T modes several times via the slide switch on the right side of the controller.  Sure enough, this brought up the compass calibration routine.
I don't know if this is old news but I found it cool way to access the compass calibration routine
	
		
			
		
		
	
				
			I don't know if this is old news but I found it cool way to access the compass calibration routine
				
		
			
										
 