mount: could not find filesystem '/dev/root'
setuproot: moving /dev failed: No such file or directory
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
switchroot: mount failed: No such file or directory
Kernel panic - not syncing: Attempted to kill init!
For me, it also took about 45 minutes to fresh compile before. I recall, but not exactly sure, that we may choose to save all the files after completion. In that case, it will drastically make the next compilation faster on top of the first one.