Worth checking out https://github.com/fosslinux/live-bootstrap which starts from a handwritten hex bootloader and later a Scheme interpreter that implements a C compiler that compiles tcc
This is hands down an amazing interpretation (some great voicing in the upper parts in the left hand, and articulation is textbook awesome) and great to see near the top of HN, his channel is worth checking out. This is better than Lugansky and the Rachmaninoff piano rolls.