Updated to Android 9
I updated MCU 3.40 and to Android 9. It was so easy on this unit. Day and night mode is nice but the lowest brightness setting is still too bright, I thought 9 improved the setting to be more linear... Speed was fine and everything worked. UPDATE: GPS doesnt seem to work with the MX HCT4 ROM... Gonna try GS's ISD 9.0 version again...
Update 2:
Well, the ROM upgrade process gave me a scare, I checked clear and format flash and the screen went black with no activities after it prompted to remove SD card.
I finally had to turn ignition off, press reset and turn on ignition, hold for 10 seconds until the buttons flash, release reset, and then press reset again. Unit booted into HAL9K and I was able to load upgrade.zip.
MX/HCT4 ROM vs GS/ISD ROM, turns out I just needed to sign into my google account for GPS to work. MX rom has bright/dark mode switch which is nice, but GS's newer ROM has better layout and easier to access shortcuts on Home page for me. Both side by side window mode works. Xtron DVR works after installing included apk on the DVR itself.
Still no AM reception I think I need the harness set for antenna ground. Also will be connecting steering wheel remote to key 1 and ground key 2.
My car has built in Sub Amp and 10" Sub, hooked to rear speaker wires I believe. Sub doesn't seem to work. It is nice Android 9 has equalization for Sub, but I need to find out what the problem is... (Update 3, turns out on Acura MDX the sub amp is turned on by Antenna Amp, and there is an Antenna Amplifier)...
Cheers!