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 ...
15
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4answers
11k views

Is a hardware-based full disk encryption possible on a Mac?

Is it possible to use hardware-based full disk encryption (perhaps on a Samsung 840 Pro SSD) on a Mac, specifically a Macbook Pro 8,2? If so, how? My understanding is that this will be handled in the ...
9
votes
2answers
376 views

How can the average user easily validate the integrity of their Mac's firmware?

How can the average user easily validate the integrity of their Mac's firmware? Before you downvote this question or lecture me on how I am paranoid and no one should ever need to do that, please ...
7
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1answer
8k views

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 ...
7
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1answer
3k views

How to clean boot menu and check/clean mbr

I had successfully installed Windows 8 Consumer Preview on my mac mini (bootcamp install) but Windows crashed during the upgrade to Release Preview and I removed it a result. But there seem to be some ...
7
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1answer
1k views

Is there any way to manually bless firmware when main disk is external?

My iMac (mid 2010) keeps pestering me to upgrade my EFI firmware to 1.8. Sadly, no matter how many times I try to to upgrade the EFI (from the manual install, or the auto update), it does not seem to ...
7
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2answers
1k views

Hide “disk password” login option at EFI (Filevault) login screen

I encrypted my volume before installation and have added my user as FileVault user afterwards. Now I can login with either the disk password or my user login password at the EFI (Filevault) login ...
6
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2answers
3k views

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 ...
6
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2answers
8k 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 ...
5
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1answer
7k views

Disk Utility says: “Error: This disk doesn't contain an EFI system partition.”

After a clean install of Lion, followed by partitioning which again was followed by a installation of Ubuntu, I noticed some error messages of Disk Utitity. When verifying the volume I get told that ...
4
votes
1answer
11k views

How to transform an Apple Mac Mini intro a reliable Ubuntu Server?

This question is about what steps are needed for transforming an Apple Mac Mini into an Ubuntu server. Here are some areas: installing Ubuntu and making it to be bootable from EFI by default ...
4
votes
1answer
2k views

How do I boot into the EFI firmware shell?

I'd like to experiment with the EFI shell on a MacBook Pro 2010 model. I am unable to find the keyboard sequence to hold on boot. Does someone know what the sequence is, do I need to boot from my ...
4
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1answer
1k views

Trapped: MacBook always shuts down during EFI SMC Update 1.8. Can't boot. How to remove updater from boot routine?

MacBook Pro i7 Mid-2012 (MacBookPro9,2) running Mac OS X 10.8.5: Downloaded the "offered" EFI SMC Update 1.8 through the AppStore Updates. MacBook restarted, grey progress bar appears w/ spinning ...
3
votes
1answer
797 views

What cool things can you do if you hack EFI

I think I'm right in thinking Intel Macs use EFI. I heard rumours that you can create low-level password protection and even install a shell. Info is sparse and limited. Have any power users hacked ...
3
votes
1answer
250 views

Does Windows, running on latest Apple computers, see boot disk partitioned as MBR or GPT?

From my understanding, the newest apple computers boot Windows in EFI mode. Traditionally, Windows has seen the boot disk as an MBR partitioned disk. In fact, the boot disk (i.e. /dev/disk0) has aways ...
3
votes
1answer
534 views

How do I restore my missing partition and install Windows 7 64-bit?

I previously had a Windows 7 32-bit installed on my Mac using Boot Camp Assistant. I recently upgraded it to Windows 10 (followed Microsoft update message), but later after I saw some drivers are ...
3
votes
1answer
253 views

Late-2013 rMBP able to install & boot Win8 using EFI?

I've previously installed Win7 (and then upgraded to 8) via Bootcamp, but I've been looking around some forums recently regarding running Win8 natively. I now have the impression that the latest-gen ...
3
votes
1answer
2k views

OS X Mountain Lion does not boot after the creation of a Fusion Drive

I have followed a guide to set up the core storage logical volume to use one SSD and one HDD. Since then, I have encountered multiple errors such as: 69822 Couldn’t rediscover disk after operation ...
3
votes
1answer
94 views

Mysterious “EFI Boot” partition appearing at startup?

A few days ago, I tried installing Windows 8.1 on my late 2011 Mac by using disk utility to make a free space on my disk and a Windows 8.1 boot drive to install. While installing, my Mac recognized ...
3
votes
1answer
2k views

What can slow down/How can I speed up the pre-kernel boot steps?

I've got a late 2007 Macbook Pro with 4 GB of RAM and an SSD. I am running Boot Camp and have an OptiBay. I have partitioned the SSD and secondary drive to devote half of each to Lion and half to ...
3
votes
1answer
405 views

MacBook Pro will not wake from sleep after installing third party application

I installed an application called Air Parrot that uses air play with an Apple tv to mirror or extend the desktop. I noticed that after I installed it, I am no longer able to wake my Mac from sleep. ...
3
votes
1answer
307 views

FreeBSD Install DVD corrupted my Mac OS X harddisk

Recently, I have tried a FreeBSD 7.4 i386 Install DVD, just to see some screens of FreeBSD on my Mac mini Intel 2006. I was going to see (to remember) just several dialog screen of and perhaps I would ...
2
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1answer
294 views

What is the difference between HFS+ and EFI System Partition (ESP)?

I'm familiar with manually installing certain files. In this case, I am installing rEFInd Boot Manager, see http://www.rodsbooks.com/refind/installing.html Yet when manually installing software on ...
2
votes
2answers
4k views

How do I keep the Recovery HD and EFI partitions from automatically mounting on my MacBook Air?

I've set Finder preferences on my MacBook Air running OS X 10.9.1 to show everything on my desktop: I've noticed that storage partitions called Recovery HD and EFI appear there: What are they? ...
2
votes
2answers
9k views

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 ...
2
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2answers
6k views

Where is the EFI stored on the macbook and is it possible to restore a previouse EFI firmware version?

I recently upgraded my macbook pro 2008 (not unibody, running 10.6.8) to mountain lion. Directly after the upgrade finished the machine ran smoothly. But after a reboot it does not boot at all (no ...
2
votes
1answer
1k views

Reset SMC: Can I use “SMCFlasher.efi -reset 1”?

I'm in a situation where I don't have working internal shift+ctrl+alt-keys and thusly unable to perform SMC-reset. Related to others' issues with SMC-updates, there are instructions for re-flashing ...
2
votes
1answer
2k views

Mountain Lion, EFI and Intel SSD Toolbox

Here's the problem: I want to do a clean install of Mountain Lion on my (custom) Intel 520 SSD inside my iMac. The first time this SSD was setup, it was done by a certified Apple Retailer. This ...
2
votes
1answer
1k views

MacBook Pro 2010 won't boot after EFI upgrade

I have updated my MacBook Pro (Core i5, early 2010) with system update to new EFI version, and now after startup it just shows the gray screen and doesen't react on keyboard (just plays the boot ...
2
votes
2answers
4k views

Any solution to bootcamp windows 8.1 with macbook pro 15" 2010?

This question may at first glance seem to be a duplicate but I am asking for an update and clarification to an unsolved problem. After extensively scanning the web, it seems that the consensus is ...
2
votes
1answer
147 views

MacBook Pro Mid 2012 startup chime from right speaker only

After installing a ssd into my Macbook pro mid 2012 (not retina), i noticed that the startup chime is coming only from the right speaker. (I am not sure if it was always like that or if its because of ...
2
votes
1answer
5k views

Dual boot Ubuntu 14.04 on a MacBook Pro

so after a few hours of Google searching and too many headaches with a broken GPT, I've turned here. I have a 2012 MacBook Pro (9,2) that I want to dualboot OS X 10.9 and Ubuntu 14.04 on. I've read ...
2
votes
1answer
303 views

How to pesistently configure a Macmini4,1 to boot after power failure?

I do have a Macmini4,1 (2010) and I want to use it as a server so it will always start even after a power failure. Please remind that I am running Ubuntu on it, not OS X. Still, based on what I ...
2
votes
2answers
400 views

How can I repair EFI?

The computer is a MacBook Air. I have OSX Yosemite and Linux Ubuntu 14.04 dual boot. I messed up and damaged my Mac EFI and hence OSX ceased to work. Recovery disk was destoyed too. FileVault is on ...
1
vote
2answers
677 views

How can I install the newest EFI firmware upgrade from El Capitan?

I've got an early 2011 MacBook Pro (8,1) and I am trying to install the newest EFI firmware upgrade, however it only supports 10.8.5 and 10.9.5. Unfortunately I have no clue as to what the best ...
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vote
3answers
65 views

Swapping HDDs w/ Different OSX Versions, Possible?

My situation: I have a "late '08 aluminum" Intel 64-bit MacBook, still have Snow Leopard installed, and XP via Bootcamp, all on the original hard-drive. Yes, it's my "legacy" setup. The HD is 7 years ...
1
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1answer
16k views

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 ...
1
vote
1answer
496 views

How to fix broken GPT, GUID and unmountable, no type volumes?

I have a Macbook Pro with retina, Yosemite and 500GB hard drive. I tried to install Windows using Bootcamp and accidentally deleted a partition, now my Mac cannot boot anymore. This is the output from ...
1
vote
3answers
119 views

Is my UEFI bugged?

I just received the new MacBook Pro 15" (with basic configuration). When I press 'Alt.' during the booting process, I don't see the recovery partition. Also, the interface is not gray as it used to ...
1
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3answers
2k views

How to enter boot menu without command key?

My Macbook air has a keyboard issue, the Z key does not work except upon startup where it becomes stuck for several seconds. This interferes with opening the boot menu on startup, because it detects ...
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3answers
12k views

“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: ...
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vote
5answers
6k views

Why I can't get out of EFI firmware update 2.7 on my MacBook Pro?

Performing the EFI firmware update to version 2.7 these days, I noticed that my 15" MacBook Pro (bought March 25, 2012) resets for five times before booting effectively. Even then, I can notice that ...
1
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1answer
3k views

Intel EFI shell on Mac

I would like to try Intel's EFI shell. How can I (build and) install EFI Shell on Mac? I've seen prebuilt binary, but I'd like do build it myself and I don't trust stuff from file-sharing sites. ...
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2answers
1k views

Applying an old EFI update on a new version of OSX

I have El Capitan running on a MacMini 2010 that I use as a media player/server. The computer used to be my mother's and I have just noticed that she has never applied any of the firmware updates ...
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1answer
512 views

Why does my Mac Pro boot to black screen with third-party video card when holding Option key?

I have a Mac Pro 2012, and recently installed a new Gigabyte GTX 760 graphics/video card. I also have Windows 7 installed on this computer on my Bootcamp partition. When I attempt to start up my ...
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1answer
4k views

What does “EFI system partition couldn't be created” mean?

When trying to click "Repair Disk" on an external hard drive from Disk Utility, I got the following error message: ... Repairing the EFI system partition's file system Updating boot support ...
1
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1answer
932 views

Set EFI to boot Windows via (U)EFI one time

On my late 2012 Mac Mini, I have installed both Mac OS X Mavericks (with FileVault) and Windows 8.1 (natively, not via Bootcamp): /dev/disk0 #: TYPE NAME ...
1
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1answer
898 views

My CPU is running slow after a system restore (4x0.8 GHz). Turbo Boost is definitely not working. And how can I fix it?

Last weekend, my Macbok Air suffered a heart attack and I ended up doing several hard shutdowns due to an unresponsive system. In the end I had to do a full system restoration. Everything is working ...
1
vote
1answer
452 views

If MacbookPro has BIOS emulation, why the need for ELILO for Linux?

I'm not fully versed in how the EFI booting process happens. If I want to install Linux in a partition formerly used by Windows, why can I not simply use LILO, installing the boot section in the ...
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1answer
401 views

How to replace a Mac hard drive with a Windows hard drive and run Windows Vista

History: My macbook hard disk failed after i dropped it and I need to replace my hard drive. I have a hard drive from a PC laptop that has Windows Vista 64-bit installed on it. Objective: I want to ...