I've recently completed an installation of OpenWRT onto this device. I wasted around 18 hours trying to get various forms and mixes of dockers, chrome add on's UNMS, UISP to no avail. I then had a thought and checked and voila! OpenWRT strikes again.
I was about to return this device, but after about 4:30 minutes I had it installed and 80% up and running. After learning DSA and finding a tutorial on this great site, it's now up and running.
I realise that there are probably other solutions to this problem, but I spent quite a long time searching (on this site and various other search engines) and didn't find anything that answered my specific question.
I turn wifi off at night and use wifi-scheduler, but it doesn't fully work on this one. It shows that all is off in Luci, but the 5GHz wifi is still up and radiating, but I couldn't connect, which was weird.
So I tested what did and didn't work and eventually found the commands that did work. This is what does work for me (below).
* 0 * * 1-4 /sbin/wifi down >/dev/null 2>&1 * 2 * * 0,5,6 /sbin/wifi down >/dev/null 2>&1 * 6 * * 1-4 /sbin/wifi up >/dev/null 2>&1 30 6 * * 0,5,6 /sbin/wifi up >/dev/null 2>&1
I've disabled WiFi scheduler tasks now.
Hope that helps someone else