For development purposes I have been using the "NodeMCU Firmware Programmer" to flash the firmware to the ESP-12 NodeMCU Dev Kit V2, and then using ESPlorer to upload the lua files.
This works well for development purposes, but now we are moving into commercial production.
Is there a faster way (one-step?) to upload both the NodeMCU firmware and lua files? I need to program between 1-5k units per month.
Yes, there is a one-step way.
You first build a file system image using spiffsimg and then flash both the firmware and the image to the device (with esptool.py I suggest).