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How to Put Your Board into UF2 Bootloader Mode

Putting your board into UF2 Bootloader forces a restart and presents a USB mass storage device in your file explorer.

All Unexpected Maker ESP32-S2 and ESP32-S3 boards ship with CircuitPython and the UF2 Bootloader installed by default.

note

The UF2 bootloader must still be present on your board -- it can be overwritten if you flash Arduino, MicroPython, or IDF code.

Steps to Enter UF2 Bootloader Mode​

  1. Press and Release [RESET]
  2. When the RGB LED turns purple, proceed to the next step
  3. Press and Release [BOOT]

Visual Confirmation​

Once successful, the RGB LED on your board will turn green once the filesystem is mounted and ready for file transfers.

Applicable Boards​

This procedure applies to the following models:

  • FeatherS2
  • TinyS2
  • TinyS3
  • NanoS3
  • ProS3

Updated on: August 1, 2023

uf2boot bootloader dfu