Only partly installed in Virtualbox

Hi, new to Alpine, seasoned in Linux.

I try to install Alpine 3.3.1 32 bit on Ubuntu 14.04 LTS 64 bit (up to date) in Virtualbox, but it behaves strange:

Installation goes on fine, I setup hostname, keyboard time zone etc and eventually reboot as requested. Machine reboots alright, but all changes are discarded: hostname is localhost, wrong keyboard and so on. If I BEFORE I reboot install nano, I can edit and save files in /etc, but after reboot nano is gone too and "apk add nano" doesn't work any more ("ERROR: unsatisfiable constraints:" blah blah)

I install to "sys". Virtualbox is 4.3.x but due to these problems I upgraded to 5.0.14 but without any changes.

So, what's going on?

Mike