[Paul Stoffregen], who heads Teensy development, has already pointed out that there needs to be allowance for the 4096 byte recovery partition in the Teensy 4.0’s storage, for example.

The chip inside is an Atmel SAMD21E18A-U, and is apparently running Adafruit’s CircuitPython platform. This discovery led to further digging, of course.

The Adafruit team have this week announced the release of CircuitPython 8.0.0, the latest major revision of CircuitPython, and is a new stable release.

CircuitPython is a full Python compiler and runtime that runs on the microcontroller hardware. “This is the third beta release of CircuitPython 6.0.0. It is relatively stable overall.