[Android Head-Units] Malcez:
Skratchuk you are a life-saver man, thanks so much!

I had a "Near Brick Experience" using the OFFICIAL Root method on the Wiki for this AN-21U.

It's important I log what happened to me because I am absolutely sure it could happen to others as well (hope this helps). This is how I near-bricked my device:

1. I put all the Root my AN21U files in SD card

2. Followed the protocol to root the device as per the Wiki at: http://direct.xda-developers.com/wiki/Tonghai_Create_AN-21_U

3. When I rebooted after the "Temp Root" step 1, I did NOT get a black screen, but all the icons were black and whilst I could run apps, all the menus were black and I could see no text. The device was at this time running predictably slowly, as the Wiki suggested it would.

4. I fumbled through in the dark icons to get the "Step 2" root step finally sorted and then managed to reboot and run Android Terminal Emulator

5. I tried to do a "su" command and got a "unauthorised" permission denied etc error! No access! Unrooted! Near Brick Experience!

6. In desperation I rebooted again and pressed the DVD button which ran the DVD app and then exited out of that. THAT RESTORED THE BROKEN DISPLAY (yay!) But it was only a temporary solution and every time I rebooted the display had black icons.

7. Multiple google searches regarding failure to execute the "su" command simply came up with android user forums and "adb shells" which is way beyond me. Basically the device was a lemon at that point.

Did this happen to you? I think the "Official" root method in the Wiki (http://direct.xda-developers.com/wiki/Tonghai_Create_AN-21_U) needs to be updated as it is potentially problematic on some newer devices with newer faceplates. My faceplate has a volume knob as well as a radio frequency knob (ie two knob model). Not the older single knob faceplate model.

How did I fix it? I followed the Skratchuk method above (just now) using that marvellous Baidu a key" root program. One thing - that Baidu program took a long time to work (longer than I expected - a few minutes). You need to be patient. Then I was able to install Superuser, It was relatively easy after that as I could run then terminal emulator and do a "su" command, do the final "rm /data/local.prop" and Bob was indeed my Uncle. The nagging "UI unauthorised error" (at the top centre of the display) from being on the updated firmware also got fixed using the modded file Skratchuk provided.

I also have a cheap knockoff ebay Bluetooth OBDII adaptor connected to the ECU of my car which does talk to Torque Pro. It works quite well. Getting it to pair took a bit of fiddling but now it works well. But the AN21U Wiki says that the Bluetooth function of this model can't do OBD. Not true. In addition I have limited Bluetooth Internet Tethering function from my Samsung S5 so that I can get some internet on my AN21 when driving. I can't quite work out why some things work (streaming radio) but not Google Maps (for example). You might ask why I want Bluetooth internet and not Wifi Hotspot from my smartphone. Wifi hotspot from my smartphone uses more battery and I have to remember to turn it off when I get to work, whereas bluetooth seems not to be such an issue, and I need to keep bluetooth on all day anyway (as my smartphone talks to my smartwatch).

Hope my near brick experience helps others. And thanks Skratchuk for your photos and method. Very easy to follow.