I have generated and exported the certificate on the /html/index?vpn.html&server page, however nothing seems to happen once I click the start button.
Where is the generated server config located and can I start the server from console via openvpn server_config?
What is the recommended way to start the server on boot-up?
It is a bug in v2.0 firmware. Could you please try the latest beta firmware? It is available in http://download.gl-inet.com/firmware/mt300n-v2/testing/
Just to be precise, V3.011 for GL-MT300N-V2 is released today.
Are my manually edited config files going to be lost once I upgrade the firmware via the web interface?
It should keep. But I suggest you back up them.