The BIOS of a system or Basic Input / Output System is a software chip placed on the computer’s motherboard that determines how the operating system will work, depending on its configuration. All Windows systems use the BIOS, while MacBook computers, which have been equipped with Intel Core Duo processors since 2006, use an equivalent called EFI or Extensible Manufacturer Program Interface, where advanced users can make specific settings at the system level. Be careful when you access this tool since a configuration error can jeopardize the stability or functionality of your system.

  • Turn off your MacBook by pressing the On / Off button once and choosing “Turn Off”.
  • Turn on your MacBook once it has completely shut down.
  • Press the following keys simultaneously, “Command,” “Option,” and the letters “O” and “F” before the system starts.
  • Press the keys until the command entry screen appears. You have accessed the BIOS equivalent of your MacBook.


How To Access BIOS in Mac

Step 1.  BIOS is entered and accessed during Start-up so as to make changes in your system configuration. Open Firmware is similar to BIOS that helps you to change some settings like changing and selecting the booting device and other configurations.
After pressing the power button on MacBook, follow the steps mentioned to access Open Firmware.

Step 2. On your PC keyboard, you can see a CMD key with an apple icon on it and an OPT key and ALT key in the same position on the keyboard. Press and hold CMD, OPT, O and F keys together. The keys O and F together stand for Open Firmware.

Step 3. A prompt “0>” will load on the screen. Type Mac-boot and press “Enter” which will let you exit the firmware and allow the continuation of booting the system.

Step  4.  Type Shut-down and press “Enter” to exit firmware and turn off the PC…