yeah, I tested the coreelec image a few moths ago and it works well with android on emmc for dual system. the key point is m2pro board has no update key, so after bootup to android first time, you must install reboot_to_LibreELEC.apk to reboot to CoreELEC on sdcard. You can also google another version of this apk and install it.
After bootup CoreELEC you can click “Reboot to eMMC” in power menu to reboot emmc android, without that you still get CoreELEC boot next time.
The issue was really with the M2 Pro coming with absolutely no documentation, and then I had to go off on a wild goose chase to get any sort of information - and then finding a solution for another device- with totally different ports.
If it was confusing for myself, I can’t imagine how bad it’d be for the average layman who came off the street buying one.
Managed to get Android 9 on it and some other goodies.