ESP32 Web Flasher
Install NFCOTS Field Server firmware
Browser requirement: Web Serial is only supported in Chrome, Edge, and Opera on desktop. Safari and Firefox will not show the device prompt. Mobile browsers don't support flashing.

1. Prepare the board

  1. Plug your Adafruit Metro ESP32-S3 into the computer using USB-C.
  2. Wait a few seconds — the OS should detect the device as a serial port.
  3. Close any other program that's using the serial port (Arduino IDE, PuTTY, etc.).

2. Flash firmware

Click the button below, select your device when prompted, and wait for the flash to complete (~90 seconds).

Your browser does not support Web Serial. Page must be served over HTTPS (or localhost) to use Web Serial.

If the button is greyed out, your browser doesn't support Web Serial. Use Chrome or Edge on Windows / macOS / Linux desktop.

3. After flashing

  1. Unplug the board.
  2. Insert your prepared microSD card (with lessons/, manifest.json, index.html).
  3. Plug power back in.
  4. On a phone, look for the Wi-Fi network NFCOTS-Field and join (no password).
  5. Open any URL in a browser — the lesson index should load.

Power users — Arduino IDE

If you want to modify firmware, the source lives in nfcots-field-server/firmware/NFCOTS_FieldServer/ in the official repo.

See build-esp32 page for required libraries and IDE settings.