A small update: it seems to work fine for about 20-25 days, and then it needs a restart, and usually one power off - power on cycle is not enough. Sometimes the WiFi hangs up, does not work, and any devices which try to connect get some sort of "failed to obtain IP address". If I "reset" the WiFi network (change channel or mode and then save), it works.
Sadly, it's been a year and there is still no way to fix this. I had faith in this device, and it was fairly expensive when it was purchased.