ESP SLIP protocol - Threetwosevensixseven/espupdate GitHub Wiki

Most end-user applications for the ESP8266-01 use the Espressif AT command set to interface with the device.

However, updating the firmware must be done with the low-level serial SLIP protocol. This is the method .espupdate uses. Read this article for technical details.

.espupdate uses the stub loader to work around bugs and limitations in the ESP's ROM bootloader.

Documentation for esptool.py can be found here.