The issue has been resolved - in a very simple way:
I just deselected Browser-Based Authentication and all worked again ! I remember that i had a look into UA config sometime, but seems i did not disable Browser-Based Authentication before switching off UA blade. This would instantly block internet access from behind the 1550, but i was far away and connected to the box from outside using internet. Same situation when updating the firmware - and i just noticed the issue after beeing home again, behind the 1150...
According to Dafna Mozel: The hotspot is disabled but the “Browser-Based Authentication” is on (Browser-Based Authentication uses a web interface to authenticate users before they can access network resources or the Internet.) Browser-Based Authentication should not be ON if user-awareness is OFF.
Will be fixed in the next firmware version.
CCSE CCTE CCSM SMB Specialist