this is called /boot/nextboot.conf. This file is required to have it's first
line be nextboot_enable="YES" for it to be read. Also, this file is
rewritten by the loader to nextboot_enable="NO"<space> after it is read.
This makes it so the file is read exactly once. Finally, the nextboot.conf
is removed shortly after the filesystems are mounted r/w.
Caution should be taken as you can shoot yourself in the foot. This is only
the loader piece. There will be a tool called nextboot(8) that will manage
the nextboot.conf file for you. It is coming shortly.
Reviewed by: dcs
Approved by: jake (mentor)