Hello Heinrich,
i was using ubports installer 0.4.18 to install UT 16.04/stable.
The re-installation of UT was successfull, I still have the apps and data from before.
I tried to reinstall Anbox, every step of the installation manual was working, except there was no success message after anbox was 100% installed.
When i checked the phone, there was an anbox window, with an activity indicator running as if something was loading, but that went on forever.
After rebooting from this state I get stuck in the boot screen again…