Flash ESP8266 from SPIFFS filesystem

Question

I'm searching for a way to flash an ESP8266 programmatically, i.e, without user interaction (and especially without the Arduino IDE).

Assuming I can put the program to be flashed on the SPIFFS filesystem, is there a way to flash the ESP with that file?

• Juraj: yes, but why store it in SPIFFS? see the ESP8266HTTPUpdateServer and ESP8266httpUpdate libraries examples
• larsb: I said I wanted no user interaction. Besides, I don't want a server in my ESP.
• Juraj: how do you get the file to SPIFFS? the ESP8266httpUpdate library downloads an update bin from a server and updates using the Updater object without storing the bin to SPIFFS.

Answer 1

Yes, it is (or at least WAS possible a few years ago) to have an ESP8266 self-program if you can get the file onto the file system, by using the Update core that is used by OTA and httpUpdate. This was a example program to do it, but I don't know if it still works. I would also suggest that you look at using LittleFS instead of SPIFFS as the latter has been depreciated.

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <FS.h>
 
void setup() {
 Serial.begin(115200);
 Serial.println();
 SPIFFS.begin();
 Dir dir = SPIFFS.openDir("/");
 pinMode(BUILTIN_LED, OUTPUT);
 digitalWrite(BUILTIN_LED, LOW);
 File file = SPIFFS.open("/firmware-update.bin", "r");
 
 uint32_t maxSketchSpace = (ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000;
 if (!Update.begin(maxSketchSpace, U_FLASH)) { //start with max available size
 Update.printError(Serial);
 Serial.println("ERROR");
 }
 
 while (file.available()) {
 uint8_t ibuffer[128];
 file.read((uint8_t *)ibuffer, 128);
 Serial.println((char *)ibuffer);
 Update.write(ibuffer, sizeof(ibuffer));
 }
 
 Serial.print(Update.end(true));
 digitalWrite(BUILTIN_LED, HIGH);
 file.close();
}
void loop() { 
}

• larsb: Perfect! This is exactly what I was looking for. Also thanks for the suggestion of LittleFS, I will consider it.

Answer 2

Yes, it still works, but now you need to pass data as a pointer:

Update.write(&ibuffer, sizeof(ibuffer));

• Juraj: it is an array so it is a pointer already