Build CircuitPython

Now we're back to following this guide

Go back to your circuitpython repository. From within ports/nrf build the circuitpython runtime with:

Upon success you should see that a build-boardname-softdeviceversion/firmware.hex and firmware.uf2 file has been built!

Installing With UF2 (Recommended)

UF2 is a drag-n-drop bootloader system and it's the easiest way to install. Locate the firmware.uf2 file in the build directory. Then drag it onto NRF52BOOT disk drive.

It will disappear and then a new drive will appear named CIRCUITPY - this is the internal circuitpython storage

Uploading with DFU (Harder)

If for some reason you don't want to use UF2, you can also use DFU which is the standard method for programming microcontrollers, it requires special software tho so we recommend UF2

Once the firmware is built as a hex we have to package it up for the bootloader in a zip file.  Do this by running:

You should see the creation of a build-boardname-softdeviceversion/dfu-package.zip file

Now all we have to do is upload it. Select the serial port that you find appears when the bootloader is running and put that next to SERIAL=

or if you have a specific zip you want to upload: