RBK50 keeps dropping 2.4GHz connections

Just unboxed new Orbi + satellite today and went about setting it up to relace a creaking network built out of three different access points (to cover large house & garden). Lots of "2.4GHz only" clients such as ESP8266, Rasberry Pi's, Electric Imps and other asorted IoT gadgets. So started by powering down all the clients I could reach after noting their DHCP reservations before disconnecting the old router (reserved IPs needed for hard-coded addresses for MQTT Brokerage, Rest APIs etc.) Next, got Orbi sync'd to satellite and entered the 20 or so IP reservations. Finally powered-on clients and watched everything come back on-line. So far, so good.

 

Then, according to the "best practice" for internet security, checked for new firmware on the Orbis. It was quite a way out of date so did the updates to RBx50 V2.2.1.210 . Note that this is within a few minutes of getting the network up and running so I didn't have time to see if there were any time-related issues (I mean, why should there be? Everything was good to begin with.) But following the update which completed OK (once I gave the satellite enough time to get its act together) clients started dissapearing one-by-one after a few minutes of connecting. Most would return after a router reboot - only to get lost a few minutes later. Powering off/on clients left them unable to make a connection when in this condition. Note that "Access Control" is not enabled.

 

Enviromentally, this is a detached house with very weak neighbouring signals so WiFi congestion is not an issue. All the client devices have been reliably working on the old AP setup despite the most distant having marginal signals. These *were* noted as being 6dB or so better on the Orbi (giving be an initial optimistic glow) but the dropped clients seem to be the ones with the better RSSIs anyway.

 

A couple of things I came across while researching this - one was a blog suggesting that the Orbi might be too powerful and that reducing RF power might help. Well, yes, some clients are close (same room as Orbi) but others have several thick walls in between so not a general solution. Also,  for wireless backhaul to have a good signal, satellite & base can't be too far apart so overlapping coverage is inevitable (overlapping coverage was another reported source of problems where devices would constantly be connected/disconnected).

 

The other thing I read on these forums was that a factory reset was recommended after updating firmware. I have not done so mainly because of the hassle of having to enter all my IP reservations - and a nagging fear that this will undo the firmware update? Saving the configuration settings and reloading is likewise discouraged. The last thing I tried was fixing the 2.4Ghz channel to 11 (as I had before and found to be perfectly reliable). This made no difference so I reverted back to my old trio of APs and the clients all returned to the LAN once more. Orbi is sat in its packaging ready to be returned unless someone can give me something else to try.

 

Having three conventional APs to extend coverage isn't great (as Android clients are bad at letting go of weak signals even when moved right in front of  another AP) which is why I took the Orbi bait. But if it can't provide basic 2.4GHz coverage, it's useless to me. Pity cos 5GHz seems to be very strong.