i also have problem setting up my rpi2/navio2… in mycase, when i apply the command sudo apt-get update && sudo apt-get upgrade , the ugrade starts but it takes a lot of time to complete… whem it completes, i reboot and raspbian is not able to boot again…
you can see my thread here… i am stll waiting for an answer though. Rpi2/navio2 does not boot after image install - #6 by george.staroselskiy