"How to firmware lock Mac Pro so not possibility to boot anyway"に関する回答How to set a firmware password on your Mac A firmware password prevents starting up from any internal or external storage device other than the startup disk you've selected. To protect the data on your Mac, you can set a user account password (login password) to prevent unauthorized users from logging in to your user account. You can also encrypt your startup disk using FileVault, so that only users who can log in to your Mac can read the data on that disk. For even more protection, you can set a firmware password. A firmware password prevents users who don't have the password from starting up from any disk other than your designated startup disk. As a result, it also blocks the ability to use most startup key combinations. How to set a firmware password These steps apply to OS X Mountain Lion or later: Start up from macOS Recovery by holding down Command (⌘)-R immediately after turning on your Mac. Release the keys when you see the Apple logo. When the utilities window appears, choose Utilities > Firmware...