Shelly Plus i4 fails to reconnect after power outage

[ddlux]

I have 2 Shelly Plus i4 devices that I use to monitor my off-grid backup power system and solar arrays.  The Shellys are powered off the battery backup power coming from the system, so they have UPS-grade battery power whether the grid is up or down.  This same backup power also powers my network: the router, the switches, and the APs.  Once in a while, we experience an extended outage where the batteries are drain to the point that the inverters shut down.  When this happens, the router, switches, APs, and the Shellys all come online at the same time.  And as a result, the Shellys get stuck in a non-connected/non-responsive mode where they never connect to the network.  I have to manually reset power to them to restart them, at which point they connect to the network as expected.  But this requires resetting a breaker which is enough of a pain for me, but really annoying when I have to walk someone else through the process if I am not here on the property.  I have observed this behavior 2-3 times in the past 24 months.  It's rare, but when it happens its a real hindrance.

The issue occurred this morning, and I was on site so I was able to do a little bit of troubleshooting when this happened.  My theory is that the Shelly boots up and tries to connect to WiFi before the APs are booted up, resulting in a failed WiFi connection.  As a result, the Shelly doesn't get into a DHCP negotiation because it doesn't even have a layer 2 connection to the network.  But a static IP address would not fix this either, because it too requires a WiFi connection.  And since the Shelly never retries to connect to WiFi, it remains in this disconnected state until I power cycle it.  While it was in this state, I tried to detect it using Bluetooth (which was enabled) through the Shelly app, but it was not detected.  I also verified that it had not enabled its own AP which makes sense, since I have disabled that.

There are various reports of this behavior that you can find online searching, but nobody seems to have a fix.  I think Shelly needs to fix this in the firmware, but I'd be open to workarounds if anyone has any suggestions there also.  And, I'm happy to file an official report if that is an option.