@NeverDie said in Bootloading a barebones arduino: You and a group of friends could sit around a table and pass bits and bytes to each other using an SPI communication protocol. Passing bits and bytes is probably more fun that sitting around a table and passing digs and barbs! I don't know: maybe my friends ARE binary! [Edit: I forgot to say anything about the content of your SPI protocol story. That was a great story; I feel badly for not thinking about the SPI connection at all. Now it is ingrained. ]