I’ve been losing my network as well. I’m now running Firmware 2.1.9 (7) on Hardware Version 2.3 – AC. I upgraded the Firmware recently hoping that would help but the problem persists. Originally, I was plugged into a TP-Link Wireless Mini Router. It would go offline often so I thought it was because the WiFi signal was weak in the garage but the router never lost connectivity so it wasn’t that. I then ran a cat5e cable to the garage, added an access point and plugged OS in to the access point. Same issue. Offline every few days. I now have OS plugged directly into my switch but the problem persists.
When this happens, I still see activity on the OS NIC port. OS screen still shows as online with the correct IP address. It no longer responds to connections. Sometimes, I’ll start responding again on its own but usually, I just have to unplug the power and plug it back it in.
I have also tried Stefan’s firmware. Unfortunately, it doesn’t seem to resolve the problem I’m having. I’ve now got a mesh system (before I had a single access point), and I think it’s a new variant of the problem (the unit drops off and back on randomly rather than just off and staying off like it did before) but it can’t complain about the strength of the signal now. Every other device in the house is rock-solid on the wifi, so it’s just an opensprinkler problem AFAICT. I still have a couple of things to try, but I’m not optimistic that this can ever be as reliable as something like this needs to be.