I am using an RT-AX88U with firmware 386.3 although I want to update to the latest. I am not certain where this is coming from but the GUI isn't as I was remembering. The upload button allows me to select a new firmware but it does not get loaded. It says "applying setting" for over 30 min and upon reboot the router was still at 386.3 instead of 386.3_2. Any suggestion ?