I have a GL-MT300N-V2 that I am using to connect to a wifi hotspot (cell phone) and share that connection to my network through the lan port.
Everything works fine, except that when I reboot or lose power to the GL-MT300N-V2 it does not automatically reconnect to the wifi network. The wifi network is in my saved networks, and I can reconnect manually and everything works fine.
If you hotspot have a fixed SSID, Key and channel, then you can hardcore this in the settings.
The config is in /etc/config/wireless. Once you fix the settings you can turn off gl_health program so that it does not detect and change your repeater settings.
/etc/init.d/gl_health stop
/etc/init.d/gl_health disable
Usually you should have a fixed ssid and key, but if you use phone as hotspot, you probably cannot set the channel. Unfortunately for MT300N-V2 you have to specify the channel to connect. If you can fix the channel of you hotspot it should be good.,