I used lede-mt300n-v2-2.264.bin from http://www.gl-inet.com/firmware/mt300n-v2/v1/

I then waited about 3 minutes before reverting the IP address.

If I need to flash the firmware again-- do I leave the router connected to the computer after updating the firmware or after the 3 minutes, do I unplug the ethernet from the computer and plug into the main modem before trying to access 192.168.8.1 to continue set up?