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?

  • 3
    yes, but why store it in SPIFFS? see the ESP8266HTTPUpdateServer and ESP8266httpUpdate libraries examples
    – Juraj
    Jul 28, 2020 at 18:55
  • I said I wanted no user interaction. Besides, I don't want a server in my ESP.
    – larsb
    Jul 29, 2020 at 16:21
  • 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.
    – Juraj
    Jul 29, 2020 at 16:35

2 Answers 2


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() {

  Dir dir = SPIFFS.openDir("/");

  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
  while (file.available()) {
    uint8_t ibuffer[128];
    file.read((uint8_t *)ibuffer, 128);
    Serial.println((char *)ibuffer);
    Update.write(ibuffer, sizeof(ibuffer));
  digitalWrite(BUILTIN_LED, HIGH);

void loop() {     
  • Perfect! This is exactly what I was looking for. Also thanks for the suggestion of LittleFS, I will consider it.
    – larsb
    Jul 29, 2020 at 16:22

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

Update.write(&ibuffer, sizeof(ibuffer));
  • 1
    it is an array so it is a pointer already
    – Juraj
    Mar 15 at 10:13

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