Uploading files to a NodeMCU ESP8266 can be done with the Java tool ESPlorer. If you want to automate this process, you’ll want to use something else. A quick research brought up NodeMCU-Uploader, which is a python script. On my Windows machine, I’ve got the bash installed. Naturally I want to use it 🙂 Fortunately the bash allows access to the COM ports. You have to modify the permissions for the device though.