I too have been getting this my broadband never stays connected for more than two weeks and i get that open rg before it disconnects and my firmware is ending .17.
My HH5 re-boots every two weeks (Open RG). I don't bother about it now as it always seems to be early in the morning so causes no problems. I run a speed test after every re-boot but it's always fine. Out of interest I would like to know why it does it though.
People who don't use a Home Hubs don't get a reboot every two weeks and their connections seem to be fine. So it is a mystery as to why the Home Hubs are the only routers in the world that need to reboot every two weeks.
"So it is a mystery as to why the Home Hubs are the only routers in the world that need to reboot every two weeks."
I'm pretty sure it's not a mystery to BT. It happens too regularly.
Same here had the Hub 4 on broadband since May 2015 was working okay until July then started reboots, have reported the problem to Tech support who book a call for an engineer to call. Engineer has been and found no fault on the line or any of the external wiring, have been passed back to tech support again who are sending another Hub 4. I have reservations on this as after doing google searches of the problem that the fault is with the Hubs software, never had any problem with my other router being a Netgear and with my previous ISP provider. I am now tempted to ditch the HH 4 and use my netgear equipment instead and then configure the HH4 as a wireless access point instead by disable the DHCP server.