I just had a 4200NEX installed, including an HDMI port so I could hopefully use Waze on the screen.  I have an iPhone 6 with the HDMI Lightning adapter.  However, when I plug in the adapter to my phone, I receive an "Incompatible USB" message and the Apps button still has an X through it.  I have tried a different HDMI cable to no avail.  I have also tested the Lightning adapter on a TV (works fine).  I did see a suggestion to change the input from USB 1 to Digital AV Adapter in settings, but it did not help.  When connected via just USB, the phone connection works fine.

Any other suggestions?  I am thinking it's a bad HDMI connection between the port and head unit.

Does it say anywhere that an adapter works with the headunit? I dont recall seeing anything myself.

If your going to use app radio in smart phone settings select Apple adapter then connect to usb1 using the hdmi Apple adapter

In settings turn off CarPlay.

If it's not working reboot phone,