Datasheet
DFU Bluefruit Updates
For videos on the latest update procedure using Bluefruit LE Connect see:
iOS: https://learn.adafruit.com/introducing-adafruit-ble-bluetooth-low-energy-friend/dfu-on-
ios (https://adafru.it/iCx)
Android: https://learn.adafruit.com/introducing-adafruit-ble-bluetooth-low-energy-friend/dfu-on-android-4-dot-3-
plus (https://adafru.it/oSD)
You can reprogram the Bluefruit LE module itself over-the-air using an Android or iOS phone/tablet. This doesn't
reprogram the ATmega32u4 in the Bluefruit Micro, only the BLE module itself. Since its not a common thing to do, its a
little challenging to do.
You will need to disconnect/unpower the Bluefruit Micro, connect a wire temporarily between the DFU pin and GND
and then power up the board via USB or battery.
The red LED will blink continuously, letting you know it's in DFU mode. Then follow our guide for field updating the
firmware (https://adafru.it/iCQ)
The video below is out of date and applies to early versions of the board before the Bluefruit LE Connect
apps were available for iOS, Android and OS X in the respective app stores. To keep your device up to date,
simply install and open the Bluefruit LE Connect app and connect to your Bluefruit device. If a firmware
update is available, it will be automatically proposed, and the entire update process will be handled
transparently for you.
© Adafruit Industries https://learn.adafruit.com/adafruit-feather-32u4-bluefruit-le Page 193 of 211










