[Android Head-Units] excitedidiot:
I have a 9.7" Tesla style unit from seicane. I bought it because it was the only large screen unit that fits my specific car(2014 Focus without Ford sync) in a clean looking way.

It's been a nightmare. It's a Mediatek based 3561s unit, with the most terrible software I've ever seen. No access to the USB debugging port without disassembling the unit.

I can adb over WiFi into a root shell(after rebooting it several times and turning USB debugging on and off. The adb connection is deathly slow, but I can get a connection long enough to copy over the su binaries, but SuperSu can't update them(but will work if I ignore the error), but the su binaries disappear after a reboot. So I can get temp root, which is good enough for me right now.

Bluetooth connects automatically, but the a2dp profile won't enable unless I open the Bluetooth app on the head unit and select the music menu. I have to reopen the menu if I get a disconnect or don't use the music for a while. I've tried forcing a2dp/music mode from the phone side, but that just fails.

The Bluetooth app is a huge ugly blocking overlay, so I can't even keep it and Google maps open at the same time. The navigation bar is huge and shows the wrong date/time.

AA won't work with the adapter they gave me, or headunit reloaded. I get a weirdly distorted horizontally oriented display that uses only about a 1/3 of the screen.

Part of me wants to trash this POS and buy another winca unit. It was slow and dumb, but at least everything worked out of the box. But I'm stubborn, so I'll probably keep hacking away at this thing until I get it right.

My current solution is pretty complicated, but it should do what I want when it's done.

I decompiled the Bluetooth app originally hoping to reskin it and make it a smaller translucent overlay, but headunit won't accept the recompiled/signed APK for install, and I'm afraid to force replace it because I don't have a way to unbrick this POS. The Bluetooth app is a very hacky version of the stock BTSuite app that came with Android 6, but with a wrapper that redirects most of the stock connection methods to another system app(xy.com.auto or something like that) that I can't reverse engineer. I've never seen an Android app like it, I can't figure out what it's doing.

Then I tried to hook into some intents I found in the Bluetooth app to try to intercept the avrcp song data, and planned to make a Tasker overlay to display the data. That didn't work because the intents only get broadcast if the Bluetooth app is on screen.

My current setup is using Navigation gestures to eliminate the bottom bar and replace it with a gesture pill. Then I have a Tasker task that runs on boot. It puts the unit in Immersive mode(getting rid of the dumb menu attached to the status bar), and starts the autoremote service and then launches Google maps on driving mode. Then it loads two Tasker non-blocking overlay scenes, one with a clock, and the other to view the current song/volume.

My phone also has a Tasker task that runs once the BT connects to the HU, that starts my phone's hotspot. I have a profile on my phone that detects changes in the music playing state, and sends a message to the autoremote service on the HU, which will update my Tasker overlay to show the song playing.

My current issues are with the Bluetooth a2dp connection, getting the backup camera to trigger, and the long time it takes to boot and load everything.

I think I found an intent I can send that should force the Bluetooth service to connect to a2dp without loading the Bluetooth app into the foreground. If that works, I'll have Tasker send that intent whenever my the music goes from stop to play.

As far as the boot time, I'm trying to decide if I want to live with it, or install a second battery(and an isolator), to keep ACC power to the unit. I'm pretty sure this will work, as the unit turns the screen off as soon as I shut off the engine and open the door, despite the fact that my car keeps ACC power on for about 5 minutes after I take the key out. If I shut the key off, open the door, and then close and restart the engine, the unit fires right back up where I left it.

If anyone wants details about how to setup Tasker like I did, feel free to ask.

Anyone ever tried a second battery for fastbooting, or keeping the ACC wire hot all the time(I don't drive the car often enough to do this without a second battery)? I don't want to go through the cost and effort of wiring this up and have it not work.