In the meantime I tried "fix OpenHDF Version info", the restart issue is solved, don't know this is casual.
Package list update still takes long instead.
However , how can I check if DNS settings are OK?
Both LAN cable and WiFi adapter were connected. Although WiFi settings were good, I found that changing the wifi adapter the issues have vanished.
Also, the old adapter caused interference with another box, so it clearly went faulty these last days.
It was an annoying but useful experience about wifi dongles!
Thanks to you all!