[ubuntu] No network if HDMI monitor is not coected?

I have bought PCG02U Ubuntu Stick PC. It is a nice and cheap device with 64-bit Intel By Trail processor (Atom) and 2 GB RAM. Everything is working fine, but I noticed that if I do not coect monitor via HDMI (actually, I am using HDMI-to-VGA adapter) before booting, device does not coect to a network. Device has Wifi and etheet coection.

However, if monitor is coected and switched of (or on), device boots normally and network comes up.

Any idea what could be the problem?

For me, it would be great if I would be able to boot the device without monitor coected, because then I can ssh to a device (directly or via OpenVPN). But without monitor coected this is not possible.

I also tried to coect HDMI-to-VGA adapter, but device still won't get the network coection...