For OTA uploads, the size of the compiled (old sketch + new sketch) should not exceed the flash size.
Due to this, large sketches (more than 500KB with 1MB flash) cannot be OTA uploaded directly if the sketch size exceeds half of the flash size.
However, this restriction can be circumvented by first uploading a sketch only with OTA features as given below:
#include <ESP8266WiFi.h> #include <ESP8266mDNS.h> #include <WiFiUdp.h> #include <ArduinoOTA.h>
char ssid[] = "xxxxxxxx"; //WiFI user id char pass[] = "yyyyyy"; //WiFi password
#define OTA_Host_Name "ESP01S-EMPTY-OTA"
void setup() { WiFi.mode(WIFI_STA); WiFi.begin(ssid, pass);
while (WiFi.waitForConnectResult() != WL_CONNECTED) { delay(5000); ESP.restart(); } ArduinoOTA.setHostname(OTA_Host_Name); ArduinoOTA.begin(); }
void loop() { ArduinoOTA.handle(); }
#include <ESP8266WiFi.h>
#include <ESP8266mDNS.h>
#include <WiFiUdp.h>
#include <ArduinoOTA.h>
char ssid[] = "xxxxxxxx"; //WiFI user id
char pass[] = "yyyyyy"; //WiFi password
#define OTA_Host_Name "ESP01S-EMPTY-OTA"
void setup() {
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, pass);
while (WiFi.waitForConnectResult() != WL_CONNECTED) {
delay(5000);
ESP.restart();
}
ArduinoOTA.setHostname(OTA_Host_Name);
ArduinoOTA.begin();
}
void loop() {
ArduinoOTA.handle();
}
This script will compile to around 300KB. Once this script is uploaded in flash, a script with upto 700KB can be uploaded through OTA to a 1MB flash!
Upload this script first. Then restart the controller and choose "ESP01S-EMPTY-OTA" as the port and upload the new updated script that you wish to upload!
IMPORTANT: Firewall must be turned OFF during OTA uploads.
