Your microcontroller ships running a factory demo. It's lovely, but you probably had other plans for the board. As you start working with your board, you may want to return to the original code to begin again, or you may find your board gets into a bad state. Either way, this page has you covered.

Factory Reset Example Code

If you're still able to load Arduino sketches, you can load the following sketch onto your board to return it to its original state.

// SPDX-FileCopyrightText: 2024 ladyada for Adafruit Industries
//
// SPDX-License-Identifier: MIT

#include "WiFi.h"
#include <Adafruit_TestBed.h>
extern Adafruit_TestBed TB;

void setup() {
  Serial.begin(115200);  
  Serial.println("ItsyBitsy ESP32 Factory Reset");

  TB.neopixelPin = PIN_NEOPIXEL;
  TB.neopixelNum = 1; 
  TB.begin();
  TB.setColor(0x0);
}

uint8_t j = 0;
void loop() {
    pinMode(13, OUTPUT);
    if (j == 255) {
      TB.setColor(GREEN);
      Serial.println("scan start");
      // WiFi.scanNetworks will return the number of networks found
      int n = WiFi.scanNetworks();
      Serial.println("scan done");
      if (n == 0) {
        Serial.println("no networks found");
      } else {
        Serial.print(n);
        Serial.println(" networks found");
        for (int i = 0; i < n; ++i) {
            // Print SSID and RSSI for each network found
            Serial.print(i + 1);
            Serial.print(": ");
            Serial.print(WiFi.SSID(i));
            Serial.print(" (");
            Serial.print(WiFi.RSSI(i));
            Serial.print(")");
            Serial.println((WiFi.encryptionType(i) == WIFI_AUTH_OPEN)?" ":"*");
            delay(10);
        }
      }
      Serial.println("");
    }
    
    TB.setColor(TB.Wheel(j++));
    delay(10);
    if (j % 20 == 10) digitalWrite(13, HIGH);
    if (j % 20 == 0) digitalWrite(13, LOW);
    return;
  
}

// SPDX-FileCopyrightText: 2024 ladyada for Adafruit Industries
//
// SPDX-License-Identifier: MIT

#include "WiFi.h"
#include <Adafruit_TestBed.h>
extern Adafruit_TestBed TB;

void setup() {
  Serial.begin(115200);  
  Serial.println("ItsyBitsy ESP32 Factory Reset");

  TB.neopixelPin = PIN_NEOPIXEL;
  TB.neopixelNum = 1; 
  TB.begin();
  TB.setColor(0x0);
}

uint8_t j = 0;
void loop() {
    pinMode(13, OUTPUT);
    if (j == 255) {
      TB.setColor(GREEN);
      Serial.println("scan start");
      // WiFi.scanNetworks will return the number of networks found
      int n = WiFi.scanNetworks();
      Serial.println("scan done");
      if (n == 0) {
        Serial.println("no networks found");
      } else {
        Serial.print(n);
        Serial.println(" networks found");
        for (int i = 0; i < n; ++i) {
            // Print SSID and RSSI for each network found
            Serial.print(i + 1);
            Serial.print(": ");
            Serial.print(WiFi.SSID(i));
            Serial.print(" (");
            Serial.print(WiFi.RSSI(i));
            Serial.print(")");
            Serial.println((WiFi.encryptionType(i) == WIFI_AUTH_OPEN)?" ":"*");
            delay(10);
        }
      }
      Serial.println("");
    }
    
    TB.setColor(TB.Wheel(j++));
    delay(10);
    if (j % 20 == 10) digitalWrite(13, HIGH);
    if (j % 20 == 0) digitalWrite(13, LOW);
    return;
  
}

Your board is now back to its factory-shipped state! You can now begin again with your plans for your board.

Factory Reset .bin

If your board is in a state where Arduino isn't working, you may need to use these tools to flash a .bin file directly onto your board.

There are two ways to do a factory reset. The first is using WebSerial through a Chromium-based browser, and the second is using esptool via command line. We highly recommend using WebSerial through Chrome/Chromium.

First you'll need to download the factory-reset.bin file. Save the following file wherever is convenient for you. You'll need access to it for both tools.

Now that you've downloaded the .bin file, you're ready to continue with the factory reset process. The next two sections walk you through using WebSerial and esptool.

The WebSerial ESPTool Method

This method uses the WebSerial ESPTool through Chrome or a Chromium-based browser. The WebSerial ESPTool was designed to be a web-capable option for programming ESP32 boards. It allows you to erase the contents of the microcontroller and program up to four files at different offsets.

You will have to use a Chromium browser (like Chrome, Opera, Edge...) for this to work, Safari and Firefox, etc. are not supported because we need Web Serial and only Chromium is supporting it to the level needed.

Follow the steps to complete the factory reset.

Connect

You should have plugged in only the ESP32 that you intend to flash. That way there's no confusion in picking the proper port when it's time!

Erase the Contents

Program the ESP32

Programming the microcontroller can be done with up to four files at different locations, but with the board-specific factory-reset.bin file, which you should have downloaded earlier, you only need to use one file.

Once completed, you can skip down to the section titled Reset the Board.

The esptool Method (for advanced users)

Alternatively, you can use Espressif's esptool program to communicate with the chip! esptool is the 'official' programming tool and is the most common/complete way to program an ESP chip.

Install ESPTool.py

You will need to use the command line / Terminal to install and run esptool.

You will also need to have pip and Python installed (any version!).

Install the latest version using pip (you may be able to run pip without the 3 depending on your setup):

pip3 install --upgrade esptool

Then, you can run:

esptool.py

Test the Installation

Run esptool.py in a new terminal/command line and verify you get something like the below:

Connect

Run the following command, replacing the COM88 identifier after --port with the COMxx, /dev/cu.usbmodemxx or /dev/ttySxx you found above.

esptool.py --port COM88 chip_id

You should get a notice that it connected over that port and found an ESP32.

Installing the Factory Test file

Run this command and replace the serial port name, COM88, with your matching port and *-factory-reset.bin with file you just downloaded

esptool.py --port COM88 write_flash 0x0 *-factory-reset.bin


Don't forget to change the --port name to match.

There might be a bit of a 'wait' when programming, where it doesn't seem like it's working. Give it a minute, it has to erase the old flash code which can cause it to seem like it's not running.

You'll finally get an output like this:

Once completed, you can continue to the next section.

Reset the board

Now that you've reprogrammed the board, you need to reset it to continue. Click the reset button to launch the new firmware.

The NeoPixel LED on the ItsyBitsy ESP32 will show a rainbow swirl while blinking the onboard LED. Then, the NeoPixel will turn green while a WiFi network scan occurs. If you open the Serial Monitor, you'll see a list of detected WiFi networks.

You've successfully returned your board to a factory reset state!

Older Versions of Chrome

We suggest updating to Chrome 89 or newer, as Web Serial is enabled by default.

If you must continue using an older version of Chrome, follow these steps to enable Web Serial.