I was able to get it to sync, and found I don't need phone on to operate - However, on a recent 600k There were a couple of times when the routing was not reliable. Also, it would incorrectly tell me I was off course, and several time it asked me to "press enter to re-configure route" ( not sure exact wording ). That led to my having to pull out, turn on and look at my cell phone RIDE WITH GPS" APP to verify where I was. Wasted time and impacted enjoyment.

Wish I'd bought the Wahoo element - some of the people I rode with really liked its rando features, though at one point the Wahoo got confused as well.