bless
Set volume boot capability and startup disk options. tldr-pages
On macOS
macOS
Bless a volume with only Mac OS X or Darwin, and create the BootX and boot.efi files as needed
bless --folder /Volumes/Mac OS X/System/Library/CoreServices --bootinfo --bootefiIdentifySet a volume containing either Mac OS 9 and Mac OS X to be the active volume
bless --mount /Volumes/Mac OS --setBootIdentifySet the system to NetBoot and broadcast for an available server
bless --netboot --server bsdp://255.255.255.255IdentifyGather information about the currently selected volume (as determined by the firmware), suitable for piping to a program capable of parsing Property Lists
bless --info --plistIdentify