Adafruit Bluefruit nRF52 Bootloader

This repository contains the bootloader for Adafruit nRF52 series and other popular boards

• Bluefruit Feather nRF52832
• Bluefruit Feather nRF52840 Express
• Nordic nRF52840DK PCA10056

adafruit-nrfutil, modified version of Nordic nrfutil, is required to perform DFU. Install python3 to your system if it is not installed already and run this command to install adafruit-nrfutil from PyPi:

$ pip3 install --user adafruit-nrfutil

This repository depends on following submodule

• tinyusb
• nrfx

Get the code with following command:

git clone <URL>.git Adafruit_nRF52_Bootloader
cd Adafruit_nRF52_Bootloader
git submodule update --init

Features

• DFU over Serial and OTA ( Application, Bootloader+SD )
• Self-upgradble via Serial and OTA
• DFU using USB Flashing Format a.k.a UF2 (Applicatoin only)
• Auto enter DFU briefly on startup for DTR auto-reset trick (832 only)

Burn & Upgrade

You can burn and/or upgrade bootloader with either jlink or dfu (serial) to a specific pre-built binary version without the hassle to install toolchain and compile the code. This is preferred if you are not developing/customizing the bootloader

To flash version 6.1.0r0 using jlink

$ make BOARD=feather_nrf52840_express VERSION=6.1.0r0 flash

To upgrade with dfu serial

$ make BOARD=feather_nrf52840_express VERSION=6.1.0r0 dfu-flash

Note: bootloader is downgradable, since the binary release is merged of bootloader and Softdevice, you could freely "upgrade" to any version you like.

Compile

Please only continue if you are looking to develop bootloader for your own. Having a jlink to de-brick your device is a must.

Option 1: Build with makefile

Prerequisite

• ARM GCC
• Nordic's nRF5x Command Line Tools

To build

$ make BOARD=feather_nrf52840_express all

To flash bootloader

$ make BOARD=feather_nrf52840_express flash

To flash SoftDevice (chip erase)

$ make BOARD=feather_nrf52840_express sd

To erase chip

$ make BOARD=feather_nrf52840_express erase

For the list of supported boards, try to type make without BOARD=

$ make
You must provide a BOARD parameter with 'BOARD='
Supported boards are: feather_nrf52840_express feather_nrf52840_express pca10056
Makefile:90: *** BOARD not defined.  Stop

Common makefile problems

1. arm-none-eabi-gcc: No such file or directory

If you get the following error ...

$ make BOARD=feather_nrf52840_express all
Compiling file: main.c
/bin/sh: /usr/bin/arm-none-eabi-gcc: No such file or directory
make: *** [_build/main.o] Error 127

... you may need to edit the Makefile and update the GNU_INSTALL_ROOT to point to the root path of your GCC ARM toolchain.

2. mergehex: No such file or directory

Make sure that mergehex is available from the command-line. This binary is part of of Nordic's nRF5x Command Line Tools

3. make: nrfjprog: No such file or directory

Make sure that nrfjprog is available from the command-line. This binary is part of of Nordic's nRF5x Command Line Tools.

On POSIX-type systems you can temporarily add the path to nrfjprog via a variation on the following command:

$ export PATH=$PATH:/Users/Kevin/Downloads/nRF5x-Command-Line-Tools_9_7_2_OSX/nrfjprog

Option 2: Build using Segger Embeded Studio

For better debugging you can also use SES. The project file is located at src/segger/Adafruit_nRF52_Bootloader.emProject.

Note

: SES only flashes the bootloader when you click download, you need to flash Softdevice beforehand if you haven't done so ( use make BOARD=feather_nrf52840_express sd mentioned above )