Use Startup Manager When you use Startup Manager to select a startup disk, your Mac starts up from that disk once, then returns to using the disk selected in. • Hold down the Option key immediately after turning on or restarting your Mac.

Feb 24, 2015 - Follow the steps below: Create a bootable drive using a USB containing Mac OS X of your choice. Plug in your bootable USB drive and Restart your Mac while holding the Option key. How To Install Linux On A Dell Laptop. When it restarts, you'll have a few options. Next, select the Disk Utility option. Jul 10, 2012. 1- USB flash drive 8G 3- TransMac. How to clean install OSX Lion from Usb or DVD. Clean Install OS X Mavericks (USB Flash Drive.

• Release the Option key when you see the Startup Manager window. If your Mac is protected by a, you can release the key when you're asked to enter the password.

• Select your startup disk, then click the arrow under its icon, or press Return. If you press and hold the Control key during this step, your selection is saved in Startup Disk preferences, so it persists until you change it. If your Mac is using OS X Lion v10.7.3 or later, you can also use this method to start up from your. Startup Manager identifies your Time Machine backup as ”EFI Boot.”. Check for Option ROM firmware If you're in and can't see your startup disk, press Option-Shift-Command-Period. If that works, do this each time you want to start up from the device or from a startup disk connected to it.

To enhance system security, Mac computers with up-to-date software don’t show devices that have Option ROM firmware until you press these keys in Startup Manager to load the firmware. On Mac models from early 2015 or earlier, you can disable this security feature to load Option ROM firmware automatically. This removes an important protection against potential unauthorized access to your Mac by other people with physical access to it.

• Open the Terminal app, which is in the Utilities folder of your Applications folder. • Type sudo nvram enable-legacy-orom-behavior=1, then press Return. To undo this command, enter sudo nvram -d enable-legacy-orom-behavior. If you're, the ability to load Option ROM firmware automatically or manually is disabled as an additional security protection. If you want to remove this additional protection but keep your firmware password: • Open the Terminal app, which is in the Utilities folder of your Applications folder. • Type this command, then press Return: sudo firmwarepasswd -setmode command -allow-oroms To undo this command, enter sudo firmwarepasswd -setmode command.