This repository provides a custom firmware and backend system for the Sonoff NSPanel smart touchscreen switch, replacing its stock interface with a Home Assistant Lovelace-like UI. The system consists of three core components: a Nextion display firmware (HMI files) rendered on the panel, a Tasmota Berry driver that handles serial communication and flashing, and a backend application running as an AppDaemon app in Home Assistant or as a standalone MQTT manager. The backend processes YAML configuration, manages localization across 38 languages, maps icons to Unicode glyphs, and synchronizes entity states between Home Assistant and the panel via MQTT. The repository also includes extensive documentation, CI/CD workflows for building Docker images and validating HMI changes, and integration examples for ioBroker and IP-Symcon. While primarily an application, it contains substantial data artifacts such as translation JSON files and icon mapping tables that support the UI.