Official support is abysmal, very focused on MicroPython and their graphical UI.
The setup impossible to achieve as it requires setting up the Yotta, just like the impossible to setup Compile MicroPython code for Micro Bit locally on Ubuntu 22.04 with your own firmware setup.
So we just use +
docker pull
git clone
cd microbit-samples
git checkout 285f9acfb54fce2381339164b6fe5c1a7ebd39d5

# Select a sample, builds one at a time. The default one is the hello world.
cp source/examples/hello-world/* source

# Build and flash.
docker run -v $(pwd):/home --rm yotta build
cp build/bbc-microbit-classic-gcc/source/microbit-samples-combined.hex "/media/$USER/MICROBIT/"
.hex file size for the hello world was 447 kB, much better than the MicroPython hello world downloaded from the website which was about 1.8 MB!
If you try it again for a second time from a clean tree, it fails with:
warning: github rate limit for anonymous requests exceeded: you must log in
presumably because after Yotta died it started using GitHub as a registry... sad. When will people learn. Apparently we were at 5000 API calls per hour. But if you don't clean the tree, you will be just fine.