I have the exact same situation/journey as @groston:
Shelly HA integration reports “Unsupported firmware”
Update > “On latest firmware - no update available”
No “Enable CoIoT” in Advanced. Only “Enable MQTT”
Enable MQTT: Shelly unofficial through HACS via MQTT doesn’t pick it up
Don’t even see any MQTT messages on boot or at any time from Shelly
curl -X POST -d '{"id":1, "method":"Mqtt.GetStatus"}' http://shelly-ip/rpc returns “Not Found”
Was about to manually create some kind of REST entity on HA when I found this thread.
Unfortunately, we don’t see this.
I was also dead-set on flashing with ESPHome borne from the frustration and weeks spent trying to get HA to detect the Shelly that is “so well supported”
I have another boxed Shelly1 that I can try but I’m certain it will be the same firmware as it was purchased at the same time.
Looks like we’re in some kind of strange firmware state so I’ll be happy to keep debugging so that it may help others in the future but I am running out of ideas.