@kriszie mount without arguments will show anything that is mounted, and where. So if it doesn't show /system than it means that partition isn't mounted, so you don't have to unmount it. Sadly, UT doesn't have lsblk, my usual go-to for finding out what devices there are, mounted or otherwise.
I took another close look at the channels and set it to stable. It says 04/16 (OTA-18). I was probably too hasty. Rotation now works for both devices.
One cm does not work at the top on one, and on the other at the bottom
With one of them, the camera works well at the front and rear. The other one stops when I want to put the camera on the back
Play video works with both only with the extra video player from the open store
@olliyze Simultaneous connection isn't automatically available with BT 5. It needs to be implemented in the software which of course isn't implemented yet on UT 😅 Inputs like play/pause doesn't work yet too but there were recent effort to make them work. Lastly, bluetooth compatibility hasn't been great with UT sadly. For example, my Xperia X stutters when playing audio to our car but it works fine on my MX4.
@c_moi ... and yet the problem is not the phone case. I decided to return Android for now, restored backup of all partitions through TWRP, loaded Android, and decided to try this case, will this "echo" under Android. There is no echo, the caller not hear himself, even when this phonecase on the phone. BTW, some kind of problem with echo cancellation under UT!
@libremax Just trying to think what I did with twrp. Wipe option, format data-select yes, then in advanced wipe repair change system and data to ext4 then reboot. Then just ran the installer with wipe and bootstrap, booted to fastboot then recovery for the rest. I do remember it took ages for the spinning circles to appear to say it was flashing the device. Remember thinking it had not worked at first. Maybe leave it a little longer rather than force reboot but bit confused I must admit.