I have ported zForth to an even weaker chip, the famous 10c risc-v micro ch32v003 (16k flash, 2k ram) so no issue running on this: https://github.com/BogdanTheGeek/zForth
Allow me to brag about romforth (https://github.com/romforth/romforth) which I ported to the "3c" Padauk and can run on really small rom/ram microcontrollers.
Caveats:
- tested only on an emulator SDCC/ucsim_pdk, not on real hardware
- given how small the ram is, there is no user dictionary but new words can be defined and tested using what the Forth folks refer to as "umbilical hosting".
Maybe, I'm not sure how you would connect a debugger to qemu, and you would have to emulate the ram and flash, but other than that is pretty standard arm cortex m0. The code is pretty generic too.
so I had to throw nginx in front of it so my little router wouldn't explode, but I hope some people will get to experience the relaxing loading experience live.