Hi, great news that touchscren finally started to work. I suppose it should start work as well for other users who reported this issue .
I made some research of this problem yesterday. Problem is quite complicated and mostly related to the graphic hardware. Original display resolution of your phone is QHD. As of Nougat release, Samsung "virtually" changed it to 1080p (rumors say due to battery drain issues), but resolution of the SurfaceFlinger remains the same (QHD). When you change the resolution, then display driver will crop the screen to the smaller resolution but SurfaceFlinger still captures the QHD.
I will try to find a way to crop and resize captured screen directly on the Head Unit but it is not so easy to do it during 1 day - alot things have to be considered to not drop the FPS rate.
Btw. for now as a temporary "workaround" I can recommend you to find an USB 3.0 HUB with additional power wire. I found one on Polish ebay (I suppose on aliexpress or similar it will be even much easier to find), and connected the additional power wire to the second USB port of the Head Unit. With this solution my Nexus 5X can even charge the battery a bit during usage of the MtcdMirroring.
I'm so glad I found this. Hooked it up and it worked on the first try. I do have to use the wqhd to get It to work silkscreen but that's ok. It is even faster than the easy connected app. I had a couple questions. It is possible to get video to work on this, like next flix or YouTube. I can get the app to open and I can see subtitles but no image. I don't know if this has something to do with the bitrate settings or not but it doesn't change regardless of the value. And if you're still taking suggestions on features, it would be nice to be able to turn the phone screen of while connected.
* Realtime streaming of touch events allows you to control your Android device by a Head Unit touchscreen.
* Realtime streaming of your Android device screen.
* Forwarding of the Head Unit key presses and Steering Wheel key presses to your Android device (You can install MtcdTools on your Phone and control it like the Head Unit).
* Automatic streaming of the audio over Bluetooth A2DP.
1. Enable USB Debugging in developer settings on your Android device.
! Owners of Xiaomi devices must enable "USB debugging (Security Settings) as well.2. Connect your Android device to the Head Unit via USB cable.
3. Accept "Allow USB debugging" when your Android device will prompt you
4. Click Connect to the device to start mirroring your Android device.
5. Explore Application Settings to customize your instance of the application.