s31-esphome ESPHome for Sonoff S31/S31 Lite with WebUI Install Copy the YAML file and the v3 folder in the esphome folder. Modify the Wi-Fi and Web Server passwords in the YAML file. Go to ESPHome, compile the YAML file, and install it onto your device. Screenshot Teardown and flashing https://www.adventurousway.com/blog/sonoff-s31