I just noticed this in the automated CI runs for the `blog_os` project: https://github.com/phil-opp/blog_os/runs/2626134888?check_suite_focus=true#step:12:47 When trying to run `cargo +nightly-2021-05-20 run`, the following error occurs:  The error message is "Failed to load rest of bootloader" and happens in the early assembly stages. I'm not sure what's going wrong yet, I will update this issue when I find the cause.