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…