To install dual boot you need a terminal (SSH) and another computer (dumb methode if you only have the box handy or SSH does not work, or your network does not see the box)
It took me a while to figure out why SSH did not work, I did not change it to active during installation, so later just turning it on did not turn it on (even if the switch was shown on ON). How should a newbie know that and why is in that case SSH not set on ON during installation?
I checked the speed from the sd slot and as usual they put it on an usb 2 port with very slow read / write rates. This is not a problem durig normal operation, but if you work with huge databases and do a backup / restore what I never done as a single file but als multiple files which are copied to each episode inclusice actor information on to the hdds.
To speed things up I wanted to have a dual boot with half of the 64GB for Android and half for CE, but as I menioined I did an error uring install and the help I got here was RTFM where this is not mentioned.
So to come to the point I cloned my, slow running ,fast sd card on to a tiny and fast USB 3 thumbnail drive, connected it to the usb 3 hub (to expand the lonly usb 3 port of the box and now I boot from usb 3 with 140 read and have a 50 write where before I was at 22/18 MB/s what slowed drastically during database operations.
Since the CE shut down menu has an option to reboot from internal memory I can switch to Android with the remote and when I shut down Android It reboot into CE.
My box has now 64MB to play wit Android and 64 GB for CE and works like a charm.
So why keep Android? To compare if I run into something where I want to see if the box behaves that way in Android also. That includes performance and temperature differences.