[MTCD Android Head Units General] SkyBeam2048:
Well, as stated above I was using MTCD HA MCU version 2.61 and found it to be compatible in my use-case. I don't remember exactly what I got it from but I think I googled it - perhaps it was linked somewhere in this thread. The initial post does not include version 2.61 but 2.59 and 2.65 which should be just fine too. Meanwhile even MTCE 2.75 is available. I didn't try this one yet.

Currently my head unit is running MTCE KLD 2.65 which is the latest MTCE firmware I could find from KLD. However I currently have issues running Bluetooth in parallel to WiFi. It works but when Bluetooth is connected WiFi connection speed drops to about 50kbps. As far as I remember I didn't have this problem with MTCD HA 2.61. I might perhaps try to downgrade once more to verify. If it works I will likely try MTCE HA 2.75 as well after.

My finding with MTCE HA 2.65 I am currently running is that MTCE seems to activate the steering wheel controls only after about minute after the HU was started. Immediately after the ignition is turned on the steering wheel buttons have no function. On the other hand I had some issues that the buttons were wrongly recognized right after the HU was woken up; so for example the "source" button and "mute" button both triggered the same action. I guess now they delay the analog-digital-converter (ADC) for the steering wheel controls until voltages are stable. Apart of this I didn't actually notice any difference.

EDIT:

I just spent some time to verify my statements.

First of all: I was wrong with my statement that MTCD HA 2.61 fixed the WiFi/Bluetooth coexistence issue for me. I just downgraded to MTCD HA 2.61 and verified the numbers with a speedtest app. Result is that when Bluetooth is connected to my phone download/upload rates drop below 100kB/s. It still works but it's simply slow. I might have to try different things like changing radio channels etc. Still to be investigated.

Then I tried to upgrade to latest MTCE HA 2.75 MCU firmware. This made no difference. It behaved exactly as the MTCD HA 2.61 for me.

However I noticed one thing and this is the reason I did not stick with the HA MCU firmware: The little screen-blank button in the status bar row used to blank the screen completely on my KLD unit. Meaning it completely turns of the screen by switching off the backlight. I personally like this a lot since during night-drives I used to switch off the screen when my favourite music or radio station is tuned so I don't need the screen. As soon as any key is pressed the screen comes on again (yes, I would prefer it NOT to do this on volume up/down events, only on home/back and other keys).

Using HA MCU firmware on my KLD unit changes the behavior of this button. It will toggle the brightness but never ever turn of the screen and backlight completely. Perhaps this is the behavior also on other HA units but I think it's stupid and useless as you can change the brightness also in the notification bar and even configure different brightness for day (headlights off) and night (headlights on) mode. So I guess HA units lack the possibility to switch off the screen.

I still didn't find a way yet how to bind this action to a steering wheel button. The screen-blanking action does not appear in the steering wheel mapping app and MTCD tools might be able to do it but I don't know the classes and arguments to bind it to a key.

So currently I am back to MCU firmware MTCE KLD 2.65d which is the absolute latest one I could find. And before you ask, I found that one here.