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Upgrading the BBC micro:bit DAPLink to J-Link

SEGGER offers the capability to upgrade the firmware on the BBC micro:bit DAPLink to a J-Link OB (On Board).

  • Fully compatible with J-Link offering the same features [More..]
  • Enables full featured development with Embedded Studio IDE
  • Using J-Link enables the use of a broad range of IDEs
  • Maintains support of HEX file Drag and Drop
  • Getting started Demo project for Embedded Studio provided



This firmware makes the on-board debug solution on the BBC micro:bit compatible to J-Link, allowing users to take advantage of all J-Link features such as ultra fast flash download and debugging speeds and the free-to-use GDB Server as well as application development using an IDE.

Download  Firmware image to convert the on-board debug interface of the micro:bit to a J-Link OB

Download  Sample projects for the BBC micro:bit that can be compiled, downloaded an debugged with SEGGER Embedded Studio

Getting Started

Just a few easy steps are needed to upgrade the firmware on the BBC micro:bit DAPLink to a J-Link OB. The following viedo walks you through the steps needed to upgrade the BBC:microbit DAPLink to a SEGGER J-Link.


BBC microbit J-Link upgrade

Step-by-Step instructions

  • Make sure that the latest J-Link software package is installed: J-Link software package download.
  • Take the BBC micro:bit and hold the reset button pressed while connecting it via USB to the PC. This will start it in maintenance mode which allows firmware updates.
  • The micro:bit will appear as mass storage device (MSD) on the PC as shown below.
  • Download and extract the J-Link OB firmware from this page (below)
  • Load the firmware - simply drag & drop the J-Link OB firmware (*.hex file) on to the MSD device
  • After the file transfer is complete, power-cycle the micro:bit, this time without the reset button pushed
  • The micro:bit will now show up as J-Link on the PC
  • To verify the connection to the micro:bit use the J-Link Commander which is a command line utility that comes with the J-Link software package

Terms of Use


SEGGER's J-Link OB firmware update for the BBC micro:bit platform, makes it fully J-Link compatible.

In order to make use of this firmware, the following Terms Of Use must be accepted:

  • The firmware may only be used for development and/or evaluation purposes. It may not be used for production purposes.
  • The firmware is ONLY for use with BBC micro:bit boards. It is not for use with custom hardware.
  • The firmware is made available without any warranty and without support.
  • No production flash programming support

If there is any doubts or concerns on a specific use case it is recommended to contact SEGGER prior to use.

When starting a debug session, a license dialog pop-up appears which must be accepted before the J-LINK OB can be used.

Firmware version history and Limitations

Firmware version history


  • Initial version


The BBC micro:bit J-Link OB firmware has some limitations when compared to the full featured industry leading SEGGER J-Link.

By using an original SEGGER J-Link PRO, J-Link ULTRA+ or J-Link PLUS, all these limitations are removed. Learn more about J-Link here.