Two firmware versions in Micro:bit


I’m using a Micro:bit board for my project. I wanted to update the firmware on the board and I went to this link:

Firmware update

I found two firmwares. One for the freely given boards and one for the commercial ones. I was surprised to find that the firmwares have a large size difference. UK-free is 97KB, commercial is 267KB. Here’s my inquiry:

  1. What’s the difference between the two?
  2. Are the Daplink chips different on these two boards? (KL26Z)
  3. Will the chip work if I interchange the firmware, i.e. if I load the UK-free hex on the commercial or vice versa, will it work?

Please help me with answers. Thanks in advance.

@JonnyA should know :slight_smile:


The devices are the same - both KL26-based and either firmware will work - the only difference is the link inside MICROBIT.HTM and the base build of DAPLink. The commercial build was built from 0243 not 0234 (so a much later build) but is functionally equivalent.

Hope that helps

Thank you for once in a while. Appreciated....