I did direct ONT a month ago. There is only a maximum 12 hours downtime and it will be from 12am to 12pm. You will be informed by StarHub a few days in advance. After 12pm, just remove the Home Gateway and connect the ONT directly to your own router. Then, power on and off the ONT. However, if you experience no internet access like what I have, you may need to reset your own router. After I did a reset of my own router, it works perfectly.