Datasheet

Device Recovery

Sometimes, bad things unfortunately happen. Thankfully, 99% of the time it's purely a SW issue and the Bluefruit

devices have a robust bootloader with some fail safes that can almost always recover your device.

How to Recover a Bluefruit Board

1. Force DFU Mode at Startup

The first step is to force your board into a special bootloader mode, which will prevent any faulty user sketches or

corrupted config data from causing problems.

Connect the DFU pin to GND with a jumper cable, or if your board has a DFU button hold the button down when

adding power to your board (connecting the USB cable, etc.)

Once the device is powered, you should see a faster DFU MODE blinky pattern that lets you know you are in

bootloader mode.

Now remove the jumper cable between DFU and GND (to prevent going into DFU mode when you reset)

2. Update the Bluefruit Firmware

Next, update your device to the latest Bluefruit firmware using the Bluefruit LE Connect app. We regularly fix bugs, and

it's always a good idea to be on the latest release.

You can perform a firmware update in DFU mode, although the Bluefruit board may appear as DfuTarg in the Bluefruit

LE Connect app, and you will will need to select the right firmware 'family' for you board.

Because bootloader mode is a fail safe mode and has a small subset of Bluefruit's features, we can't tell the Bluefruit

LE Connect app very many details about our HW. As such, you will need to indicate which firmware type to flash ...

specifically, whether to flash the UART of SPI based firmware. Be sure to select the right one, based on your product

and the table below:

BLEFRIEND32 Firmware (UART, 32KB SRAM)

Bluefruit UART Friend V2 (https://adafru.it/edl)

Bluefruit LE UART Friend (https://adafru.it/tYD)

BLESPIFRIEND Firmware (SPI)

Bluefruit LE SPI Friend (https://adafru.it/fLp)

Bluefruit LE Shield (http://adafru.it/2746)

Bluefruit LE Micro (https://adafru.it/tYE)

Feather 32u4 Bluefruit LE (https://adafru.it/tYF)

Feather M0 Bluefruit LE (http://adafru.it/2995)

3. Flash a Test Sketch

Once the core Bluefruit firmware has been updated, flash a test sketch to the device from the Arduino IDE, such as the

following blinky code:

Remove the jumper cable between DFU and GND once you are in DFU mode so that you exit it during the

next reset!

