TelegramOTA

Remote OTA firmware updates for ESP32 via Telegram. Flash from anywhere — no LAN, no port forwarding, no USB after the first time.

By Wyltek Industries · Companion to TelegramSerial

How it works

1. Build your sketch → export .bin
2. Send /flash to your bot with the .bin attached
3. Device downloads, verifies, flashes, reboots
4. New firmware reports back: ✅ Running v1.1

Install

Arduino Library Manager: search TelegramOTA

PlatformIO:

lib_deps = toastmanAu/TelegramOTA

Quickstart

#include <WiFi.h>
#include <TelegramOTA.h>

TelegramOTA ota("YOUR_BOT_TOKEN", "YOUR_CHAT_ID");

void setup() {
    WiFi.begin("ssid", "pass");
    while (WiFi.status() != WL_CONNECTED) delay(500);
    ota.begin("1.0.0");   // version string — shown after flash
}

void loop() {
    ota.handle();         // polls Telegram every 5s
}

Commands

Command	Action
/flash + .bin	Flash new firmware
/rollback	Revert to previous firmware
/reboot	Restart device
/status	Heap, uptime, RSSI, flash usage
/version	Firmware version + build date
/log	Last 50 log lines
/help	Command list

Remote debug loop (with TelegramSerial)

#include <TelegramSerial.h>
#include <TelegramOTA.h>

TelegramSerial tgSerial(BOT_TOKEN, CHAT_ID);
TelegramOTA    ota(BOT_TOKEN, CHAT_ID);

void setup() {
    // ...WiFi...
    tgSerial.begin();        // Serial → Telegram
    ota.begin("1.0.0");      // OTA via Telegram
}

void loop() {
    tgSerial.handle();
    ota.handle();
    // Serial.println() now streams to your chat
}

Full remote dev loop: push code → build → /flash → read serial output — all from Telegram.

Log buffer

Replace Serial.println() with ota.log() to keep a ring buffer accessible via /log:

ota.log("Sensor: " + String(reading));

Callbacks

ota.onFlash([](bool ok, const String& msg) {
    // called after flash attempt
});

ota.onProgress([](size_t written, size_t total) {
    // called during download
});

ota.onCommand([](const String& cmd, const String& args) -> bool {
    if (cmd == "/sensor") { /* handle */ return true; }
    return false;  // let TelegramOTA handle it
});

Rollback

If new firmware crashes on boot, the previous firmware is still in the inactive OTA partition. Send /rollback to revert (requires the device to be at least partially booting and connected to WiFi).

For automatic rollback on crash: call esp_ota_mark_app_valid_cancel_rollback() in your setup once you're happy the firmware is stable.

Security

• Only the configured CHAT_ID can trigger OTA or commands
• Add additional authorised chats: ota.addAuthorisedChat("987654321")
• All Telegram traffic is HTTPS

Configuration

Override in platformio.ini build_flags:

build_flags =
    -DTOTA_POLL_INTERVAL_MS=3000    ; poll every 3s (default 5s)
    -DTOTA_LOG_BUFFER_LINES=100     ; bigger log buffer
    -DTOTA_CHUNK_SIZE=2048          ; larger OTA chunks

Requirements

• ESP32 (any variant)
• ArduinoJson >= 7.0.0
• WiFi connection with internet access