Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware

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How to fix broken EFI partition?

I have an iMac running OSX Lion. I also installed bootcamp and Windows 7. During the install of Windows 7 I wasn't paying complete attention and deleted and formatted the EFI partition. I didn't ...
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How to downgrade EFI firmware back to version 1.6

I'm trying to get a SATA III hard drive to work in my MacbookPro5,1. I think I've finally figured out that if I downgrade the EFI firmware to version 1.6, my computer will negotiate the link at SATA 1 ...
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1answer
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What does boot.efi actually do?

I understand that when a Mac's EFI system runs, it locates the file boot.efi in the /System/Library/CoreServices/ (blessed) directory and runs this as an EFI application (subverting a large part of ...
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Why does Disk Utility create EFI partitions on external disks?

A technical told me about the EFI partition that... ...it's only there in case your computer will do an EFI update so the update files can be loaded onto the EFI partition. This is consistant with ...
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2answers
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Unsupported hack or workaround to get 64-bit OS X to install on a MacBook Pro having only 32-bit EFI?

I want to install the 64-bit OS X 10.7 on my MacbookPro 2,1, which has a 64-bit processor, but only 32-bit EFI and Kernel Boot mode. I know that this is not officially supported, but I assume there ...
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0answers
406 views

Macbook Pro: How to disable discrete GPU permanently from EFI?

I'd like to disable the NVideo GTX 750M GPU on my Macbook Pro 15" (Retina, Mid 2014, OSX 10.10 Yosemite). I know I can use GfxCardStatus but I read I could have a more permanent solution by changing ...
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1answer
305 views

Creating a EFI partition

I have been having trouble installing OS X Mavericks and I think I found the problem. It told me I couldn't boot up with Macintosh HD, so I verified my disk and I got this error: This disk doesn't ...
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“No Bootable Device” after failed Boot Camp installation (Windows 8 - 1TB Fusion Drive)

On my new iMac /w a 1TB Fusion Drive, I tried to install Windows 8 (still technically unsupported) using the following method: ...