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Howto flash micropython to Heltec WiFi LoRa v3

Author: @GillisICWE Date: 21-10-2025

This guide will walk you through the steps to flash micropython firmware onto a Heltec WiFi LoRa v3 device.

Download micropython firmware (Micropython ESP32-S3 Firmware)​

Download the latest micropython firmware for ESP32-S3 microprocessor from the official micropython website: ESP32_GENERIC_S3 At the time of writing this guide, the latest stable version is ESP32_GENERIC_S3-20250911-v1.26.1.bin

Requirements​

  • Heltec WiFi LoRa v3
  • USB-C cable
  • Computer with internet access
  • esptool.py installed (can be installed via pip: pip install esptool)

Steps to flash micropython​

  1. Connect the Heltec WiFi LoRa v3 to your computer using the USB-C cable.
  2. Use following python script to flash micropython firmware to the device:
import os
import sys
import time

os.system("python -m esptool --chip esp32s3  erase-flash")

os.system("python -m esptool --chip esp32s3 --baud 460800 write-flash  -z 0 ESP32_GENERIC_S3-20250911-v1.26.1.bin")
  1. Save the script as flash_micropython.py and run it using the command:
python flash_micropython.py
  1. Wait for the flashing process to complete. You should see output indicating that the flash was successful.

Verify the installation​

  1. Open thonny
  2. Select the interpreter: Tools -> Options -> Interpreter -> MicroPython (ESP32-S3)
  3. Select the correct port for your Heltec WiFi LoRa v3
  4. Click on the Stop/Restart backend button (green circular arrow)
  5. Write the following code in the editor and run it: (Freenove Basic Starter Kit for ESP32-S3)
from time import sleep_ms
from machine import Pin,SDCard

led=Pin(35,Pin.OUT) #create LED object from pin2,Set Pin2 to output

try:
    while True:
        led.value(1)        #Set led turn on
        sleep_ms(1000)
        led.value(0)        #Set led turn off
        sleep_ms(1000)
except:
    pass
  1. Press the Run button (green play button) to execute the code. The onboard LED should start blinking, indicating that micropython is successfully installed and running on your Heltec WiFi LoRa v3.

Congratulations! You have successfully flashed micropython to your Heltec WiFi LoRa v3 device.

Bronnen

  1. MicroPython. (n.d.). ESP32_GENERIC_S3 firmware. Geraadpleegd op 21 oktober 2025, van https://micropython.org/download/ESP32_GENERIC_S3/
  2. Freenove. (2023, 15 maart). Freenove Basic Starter Kit for ESP32-S3: Getting Started with MicroPython. Geraadpleegd op 21 oktober 2025, van https://github.com/Freenove/Freenove_Basic_Starter_Kit_for_ESP32_S3/tree/main/Python/Python_Firmware