If someone is interesting about how to bootstrapping, this[0][1] tutorial is just awesome, tiny compiler from nothing (raw machine codes and hex!) to the self-hosting!

[0] https://web.archive.org/web/20120712111627/http://www.rano.o... [1] https://github.com/certik/bcompiler (Fork in GitHub)

Also worth check - https://www.t3x.org/t3x/book.html :-)