Skip to main content

Updating Pro Micro Bootloader to DFU Bootloader

Work in Progress

This page is not complete yet.

Partially adapted from Drashna's DFU Flashing Guide

This guide will cover updating the bootloader of the Pro Micro from the stock Caterina bootloader to the DFU bootloader.

Why change the bootloader

Why would you update the bootloader?


  • Caterina bootloader only stays in bootloader mode for about 8 seconds when reset is triggered, while DFU stays in bootloader mode when reset, allowing for a better flashing experience
  • Don't have to figure out what COM/tty port the Pro Micro ends up on when trying to flash, which is one of the main problems with flashing on Windows

Equipment needed

  • A Pro Micro you want to flash with DFU bootloader
  • An ISP flasher - a couple options here
    • A real one like USBasp
    • Another Pro Micro!
  • 6 wires - solid-core recommended, 22-30 AWG