I would like to know if is it possible to write file for example directly to flash memory of ESP8266 from microcontroller. I know, it exist standalone microcontroller in ESP8266 but in my application, I use my own microcontroller to acquire data and store it in sd card through file system. The aim is to transmit this file to flash of ESP8266 in order to create an ftp client using to send finally this file to server like filezilla.
Thank you for your help
Warmir