If a devices or sensors is already registered it should return 200 with the existing UUID, instead of 209 (already registered), because easier to manage when you update firmwares reflashing it

[Ks89]

[Ks89]

If I format the ESP32 and try to register it again, it will give me status 209 and will no longer get the UUID trying to boot it with no UUID in memory and no way to get it, unless removing the device by hand from the DB and then restarting the 'esp. Actually, 209 should be used to always return the UUID, or directly return 200 with an "already registered" warning message and the UUID!!!!