ESP8266 Community Forum

Hi all,

Does anyone know of a way to directly read and write to and from the EEPROM of the ESP8266? By this I mean upload or download a hex (or somthing similar) to the EEPROM storage from a PC without touching the flash. I'm thinking something like an equivalent to

as used in avrdude.

I can't see anything in the ESP8266 DownloadTool that looks like it will do this, and I can't find anything on Google as it just brings up articles about manipulating EEPROM from within your software.

I am aware that I could have 2 pieces of software, one initial program that populates the EEPROM, then the actual software I want to run, but that's not quite the solution I'm looking for.

As for the rationale behind my request, I would like to bulk program a load of ESPs with software (or even get a supplier to do it) that looks for data (e.g. serial number) in the EEPROM. Then at a later time just upload a small file to the EEPROM with said data in, without having to reprogram the ESP entirely.

Any thoughts?

EEPROM doesn't really exist in ESP8266, it is only an emulation done in Arduino-ESP framework, and this EEPROM bits are stored inside the Flash at location just after the SPIFFS location, before the WiFi configs.
https://github.com/esp8266/Arduino/blob ... OM.cpp#L44
You can directly access it with esptool.py at the following location with the sector size is 4096 :

EEPROM library uses one sector of flash located at 0x7b000 for storage.

Although this 0x7b000 could vary depending of the flash size and SPIFFS size.
http://esp8266.github.io/Arduino/versio ... ystem.html

Thanks! That's just the info I needed.