Ninebot ESX Firmware
Firmware is essentially the Operating System for the scooter's different parts.
Each part runs a different firmware.
If you need to find a file relating to the original firmware for the ESX (ES1, ES2, ES3, ES4) or SNSC 1.0/SNSC 1.1, this is the place.
All firmware files are hosted at ScooterHacking.
Always make sure you are getting your firmware files from a reputable source to avoid issues.