Use CircuitPython with nRF52840 Micro Dev Kit USB Dongle

On the CircuitPython website there a build of CircuitPython 6 in UF2.
I have put the the nRF52840 dongle pressing the user button and it shows the MDK-DONDLE drive
I have copied the UF2 CircuitPython firmware in the drive and when it was finished the dongled restarted.
Up to here everything looked good.
But now I don’t see the CircuitPython drive therefore I can not use CircuitPython.
What should I do?

I finally succeded on loading CircuitPython on the MDK dongle. I got some help in the Adafruit Discord channel. I can say that I’m quite disappointed about total absence of support from Makerdiary.

Anyway, let’s change subject now. The USB Dongle comes with an UF2 bootlaoder but this bootloader is not good for circuit python. In order to use circuit python you need to change the bootloader. Please, be aware that if something fails it may brick your MDK dongle and then you need J-Link to fix it.

  • Go in DFU mode and load the CircuitPython image on the MDK Dongle drive CircuitPython download
  • Download the Adafruit bootloader mdk_nrf52840_dongle_bootloader-0.3.2_s140_6.1.1.hex
  • Convert the bootloader in .uf2 format with this command: mdk_nrf52840_dongle_bootloader-0.3.2_s140_6.1.1.hex -c -f 0xADA52840
  • Go in the DFU mode and load the .uf2 bootloader

So sorry for the late reply. I will see how to build a CircuitPython firmware for our default UF2 bootloader. It should not have much change.

I tried this and it works well!
I am interested in writing a custom bootloader to load onto the mdk52840 dongle also.
How did you get your bootloader to load as a UF2 file?
I thought it was the flash settings which I have set to
FLASH (rx) : ORIGIN =0xE0000, LENGTH = 0xFE000-0xE0000
but this doesn’t work.

What did you do to get the update of the bootloader to take?