This core is edited for the D6 Fitness Tracker, it is original from here https://github.com/atc1441/D6-arduino-nRF5, which has much of the documentation.
- Download and install the Arduino IDE (At least v1.6.12)
- Start the Arduino IDE
- Go into Preferences
- Add
https://ljunquera.github.io/package_smartwatch-boards_index.json
as an "Additional Board Manager URL" - Open the Boards Manager from the Tools -> Board menu and install "D6 Tracker by ATC1441"
- Select the DSD6 Tracker board from the Tools -> Board menu
- You will find the DFU update file in a folder like this on windows.
C:\Users\USERNAME\AppData\Local\Temp\arduino_build_RANDOM\SKETCHNAME.ino.zip
Make sure to have Sandeep Mistry's boards platform installed https://github.com/sandeepmistry/arduino-nRF5#board-manager