For the record, the below response is verbatim what I received from Eonon customer support to some of my comments/issues:
"Thanks a lot for your great tips, I think it will help many guys.
About the issues you mentioned, I would like to answer one by one:
When using the phone the unit is locked up in phone mode. I could not move to any other screen or App. Not Navigation, not Home screen, nothing. Not exactly convenient if you want to look at your NAV page to tell the person on the other end you are XX miles or minutes away from destination.
-->As for your safety, the unit is designed like this way, we just want you to pay attention to the call only.
Camera interference and no camera image appears during engine running. Camera image appears when engine not running. I am using the reverse light positive and negative wires as power trigger for camera. It is thought that there is voltage regulation on the lighting circuits of the E53 and that a "cleaner" source of voltage power is needed. I am installing a relay which will simply use the reverse light voltage to close contacts that will supply a cleaner/unregulated source of power for the camera. This you should resolve with your R&D people on the exact way a camera should be connected in this SPECIFIC vehicle. This reflects badly on your camera product and head unit.
-->Thanks for your message. About this phenomenon you mentioned, it should be that your car can't provide enough power for the camera to work when the engine is running, so a relay will resolve this issue.
After re-naming the BT in my unit to X5 Eonon and connecting up the first few times, the unit boots up and now automatically calls itself "CAR KIT". I changed "CAR KIT" once to "X5 Eonon" and on a subsequent boot up it went back to "CAR KIT".....BT functions fine but where CAR KIT came from and why it keeps coming back is a big mystery.
-->About this issue, let me check with our techs first and will let you know the result soon.
Screen presses and subsequent finger smudges are quite noticeable in the screen. Possibly due to the glare in the screen and/or angle of screen. I will install the supplied glare screen and see what happens.
-->As the unit has the screen protector, please plull it out for checking too.
In daytime, max illumination is needed and today wash't even a fully sunny day in Wisconsin. Night illumination at 1/2 brightness was fine for me.
-->You can set the brightness for checking.
Also, the camera I received from you projects a reverse image on my screen. When I stand on the left side of the car at the rear, my image appears on the RIGHT side of the screen.
-->You just set it by this way:
Settings--->driving settings--->reversing X-mirror, then it will be OK, please have a try.
Many thanks for your kind understanding."
So apparently, the phone use locks everything out by design
It's nice that the unit settings will reverse the camera image.
Mike