Reboot VirtualBox macOS into recovery

Theoretically hitting esc at the VirtualBox logo during startup should drop you into EFI, but I can’t get it to work.

The following does work (https://github.com/geerlingguy/macos-virtualbox-vm/issues/46#issuecomment-647807097):

sudo nvram recovery-boot-mode=unused && sudo shutdown -r now

Not sure whether you need to

nvram -d recovery-boot-mode && shutdown -r now

to get out of recovery or whether recovery will just do that itself when you restart normally.