Sonoff Basic “R3” is still the Cheapest Wifi Switch for home automation. With this newest version they included a new stock firmware option that allows you to boot in “DIY Mode”. The best part about that, is it allows you to load 3rd party firmware like Tasmota, ESPhome, ESPeasy, etc without soldering and without a USB/Serial adapter.
Here are the Steps:
1. Setup and Update to latest version of eWelink firmware
2. Apply “Magic DIY” jumper
3. Create Wifi SSID: sonoffDiy