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?
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() {
}
Yes, it still works, but now you need to pass data as a pointer:
Update.write(&ibuffer, sizeof(ibuffer));
