The latest release of ARM uLisp, Version 3.6b, now lets you save an image of your entire Lisp workspace to flash memory on ATSAMD21 boards that don’t provide a separate DataFlash chip.
This adds support for save-image to the Adafruit Neo Trinkey, Adafruit Gemma M0, Adafruit Feather M0, Arduino Zero, Arduino MKRZero, and Seeeduino Xiao M0.