That's unfortunate about the power issue still that you were trying to resolve. I guess the pass-thru battery power option wasn't successful in maintaining constant power? Would you have the same issue if you power directly the Pilot's battery? Always the possibility of using the timer (page 2) and connect directly to the Pilot's battery. The timer would cut power after x mins/hours/days. Not sure if the timer resets when the trigger action receives power. Trying to provide a solution that won't drain your battery but eliminates the power-up issue (I previously was using an google chromecast audio device and the boot time was annoying to me so that option was replaced with my current solution). So annoying stopping to get gas or groceries and then waiting what seemed like 5 mins for it boot and connect again.Hey again. Yes, I'm using a 2013 Google Nexus 7 tablet with a magnet mount along the top edge of the radio area. It works really well for Carplay as long as you can put up with the power cycling issue and the setup of the tablet. The Fire 8 HD may not have the power cycling issue that the Nexus has (basically if the dongle is not recognized when you fire the ignition, you have to restart the tablet. This happens to me about 50% of the time after stopping and starting the vehicle (power is cut to the carplay dongle and its not always recognized by the tablet after it has been shut down in this manner - the Fire tablet may handle this better, I'm not sure).
For mounting the tablet, I do have a fairly good solution for that. I picked up a magnet mount that is just about the right thickness that when mounted above the radio, on the 1" semi-curved lip along the top of the radio area, it allows a really good fit and you can still see the Pilot's info display screen.
All in all, I'm pleased with the solution and I've gotten used to working with the power cycle issue, restarting the tablets when needed is just two clicks on the screen and it restarts pretty quickly.