Tried to get the gateway working once more, after some time of inactivity. Today, I managed to update the firmware to v1.0.5. There was a short moment when the gateway seemed to be fully connected. But, it is again back to the sequence of the fourth led flashing, then rebooting. Activation of the gateway appears to be complete.
It could be that the local network is the cause of all trouble. It is a Fritzbox on Xs4all ADSL. But, the gateway has unrestricted access to the internet.
To check an alternative, I also configured the gateway to connect to the internet via my iPhone’s hotspot. But, it all does not make a difference.
I am running out of options for things I can do myself. Not willing to buy additional controllers or toolkits to get low level access to the gateway: no more funds to this device because it has not worked a second yet.
Anybody has suggestions on how to get the gateway connected and working?