You should be free to explore without worrying about bricking the thing — ESP8266 comes with a built-in bootloader that’s very robust. I’ve never seen a case where the bootloader is corrupted. Because OpenGarage firmware supports over the air (OTA) update, there is actually no need to update firmware through the USB cable — of course you still need the USB cable to provide power — but the firmware can be uploaded through the webpage. Also, OpenGarage firmware is written in Arduino with ESP8266 core, it does not use Lua / nodemcu at all.
