Just like everyone, I had issues trying to use the unit after my first initial setup.
I'm not actually sure what I did to fix it but I used Mirroid to play with the settings on the CarDroid.
You'll need Mirroid and MT65xx Preload Auto-Driver (links below). Mirroid will allow you to plug the CarDriod into your PC and use it as if your PC was your headunit.
Here are the things I changed/played around with.
- I re-established Bluetooth with my car headunit. Deleted and Added my car headunit to Bluetooth (using a Bluetooth app I downloaded from Play Store)
- I enabled Developer Settings (using a Settings app I downloaded from the Play Store)
- I changed USB connection type to MTP
- I disabled USB Debugging (you will loose connection to your PC as soon as you do this). The unit will always boot with USB Debugging on
Here's a short video of it in action - https://www.youtube.com/watch?v=C_boh6huMjE
Mirroid - https://en.mirroid.com/
MT65xx Preload Auto-Driver - https://androidfilehost.com/?fid=1322778262904018626