CircuitPython is open-source software and you can build it yourself! This new guide will give you the basics for setting up your build environment and how to get started building your own firmware images of CircuitPython. You might want to test the latest changes before a release, tweak some settings, turn features on or off, or add frozen modules to your firmware images to save RAM space.
We’ll add more details to this guide over time, but for now, this should get you started. If you have more questions feel free to ask in the #circuitpython channel in discord (https://adafru.it/discord) or in the support forums.