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

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Why does my external HDD have an EFI partition?

When I ran diskutil list on my Mac, it showed an EFI partition plus my normal partition on my external disk. Why is it there? If I edit my EFI partition and it gets corrupt, will a format change it ...
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15 views

Create EFI partition on external HDD for rEFInd

How can I install Ubuntu and Windows onto my external HDD which already has OS X installed on it? I want to install it using rEFInd boot manager. If I can create an EFI partition for my drive then I ...
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2answers
100 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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1answer
155 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 ...
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0answers
44 views

Issue with OS X Startup Disk in System Preferences when using EFI dual boot

I have Windows booting EFI on my Mac mini (Late 2012). It has two physical drives with one EFI partition (on the OS X disk). If I option boot I see OS X and EFI (Windows) choices and everything works ...
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1answer
68 views

EFI automounts on startup

After upgrading to the newest El Capitan from 10.10. to 10.11.1 - I guess - the normally invisible EFI partition appears on the desktop as a regular volume on different machines, if I choose to show ...
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14 views

15" MacBook Pro (2011) i7, 16GB ram, 1TB hybrid drive. EFI problem [duplicate]

Have been running in Win7 for awhile and needed to boot into Mac El Capitan. Option had my normal icons but my Mac partition now is labeled EFI Boot. Other icons are my Windows partition and Recovery ...
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1answer
135 views

GRUB 2 - “fb: swiutching to radeondrmfb from EFI VGA”

Whenever I try to boot Arch, Mint or Debian from a USB stick using GRUB 2 on my mac with compatibility mode, it freezes on this error (given in the question title). I've tried every available, up to ...
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1answer
445 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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167 views

Mac Pro, Boot into OSX without EFI after Bootcamp

I have a Mac Pro, early 2008. I installed Windows 10 using bootcamp. The mac came with an 8800gt, but I had a GTX680 from my other PC which I put in the mac, it is not the mac version so I don't get ...
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2answers
265 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 ...
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266 views

What is /Volumes/firmwaresyncd?

I keep seeing this in my logs: > 10/5/15 3:45:16.532 AM deleted[366]: normalizeUserMountpoint:738 > volRoot failed for /Volumes/firmwaresyncd.G3PNKw What is it? Is it related to the firmware ...
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0answers
227 views

How to use Testdisk under OS X recovery mode?

I accidentally broke the GUID, I suppose, when I was trying to solve the incorrect EFI partition problem. What I have now is: Disk1 is a 4 GB thumb drive with a recovery partition (disk1s2) I ...
0
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1answer
276 views

How to change the GPT partition type of an EFI partition?

I have a perplexing problem with the EFI partition on my boot SSD. The GPT partition type is "Microsoft Basic Data". On all other drives in my system, including my Carbon Copy Cloner clone of my boot ...
0
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1answer
100 views

Boot from external USB3

I've recently bought an usb3 flash drive where I've put a live kali linux distribution. When I try to boot my early 2015 mac book pro (with Yosemite) from this usb3 drive I have two options: windows ...
0
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2answers
355 views

Getting my MacBook Air (2011) into Windows faster

Is there a way to reduce the time spent in EFI? It seems more than 15 seconds that the Mac (Macbook air 2011) stays with the screen grey before beginning to boot (or resume from hibernate) to ...
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0answers
139 views

HFS+ external drive missing EFI, will not mount on Mac

First off: Fear not, I have everything from this drive backed up. I'm just trying to reformat it, but I had someone else attempt it on Windows which doesn't look like it helped. I'm a novice but ...
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307 views

Efibootmgr command for OS X

I have successfully been able to install Linux Mint on my Mac. The only issue is I cannot select the boot partition holding option. To fix it I booted into linux and ran sudo efibootmgr -o 1,80. This ...
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1answer
95 views

Resizing system partition

When I installed OSX Mavericks, I left free space after my system partition in case I wanted to install a second OS there. This has proved unnecessary — I've never modified the partition table — and ...
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0answers
131 views

Corrupt EFI Partition or Error b/c of Encryption? & Ghost Partition

I have a 2012 Mac Mini Server with two internal SSDs. Until recently, I had Mt. Lion installed on one of the SSDs, as my only boot drive, and used the other, rarely, for file storage. I created a ...
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2answers
593 views

Unable to use gpt to restore efi partition

I accidentally deleted my efi partition, which I now know is bad news bears. I found a guide here to restore it without losing data, but even though I'm booting from usb and have unmounted all ...
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3answers
116 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 ...
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1answer
411 views

How can I get Windows to install in Legacy (BIOS) boot on my mid-2012 MBP

I've got a 13" mid-2012 MBP running OS X 10.10.3 Yosemite. I've recently repaved it with a fresh install and now I'm getting round to Bootcamp`ing it. I've installed Windows 8.1 in EFI boot mode and ...
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1answer
375 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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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 ...
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1answer
240 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
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2answers
338 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 ...
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86 views

Add an exeption to the Apple EFI (option) boot menu

I have just installed Ubuntu on a partition of my HD. I am using a MacBook Pro Mid 2012. I know that to launch Ubuntu, you need a third party EFI booter such as rEFInd. I have installed that, but I ...
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59 views

Reset MacBook Pro Boot Location

I logged into my friend's MacBook Pro 13 as Guest User to install OS X Yosemite on a USB flashdrive. I downloaded the Installer from the Mac App Store and stored it somewhere within the Guest User's ...
0
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112 views

Upgrading a 1st Gen Macpro to 64-bit EFI

I'm still running my trusty 2006 MacPro 1,1. After various upgrades and mods which have all inexpensively helped performance no end I'm contemplating upgrading the machine's 32-bit EFI with the 64-bit ...
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375 views

Does Apple's EFI patch Thunderbolt devices to Windows 10?

So, I've been rattling with myself about this for a bit. I've followed 5SH-2a's guide of EFI Bootcamp to no avail. I decided to try it on my own, by mapping an NTFS Partition on my hard drive to a ...
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50 views

Verify the EFI firmware

I'd like to copy the EFI firmware currently installed on my MacBook Air to a file on disk, so that I can compare it with the EFI firmware on other machines. I've seen advice on reflashing the EFI ...
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4answers
3k views

How to setup two OS X boot partitions plus Bootcamp and Data?

Is it possible to set up he following combination of partitions; how? two OS X partitions, each bootable (one for the main system, another for testing new OS X releases) a Bootcamp bootable ...
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1answer
414 views

MacBook Pro Mid 2012 Windows 8 install on SSD

I am trying to install Windows 8, efi, on my SSD. I am getting the error code: 0xC0000005 "Windows installation encountered an unexpected error. Verify that the installation sources are accesible, ...
2
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1answer
138 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
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1answer
217 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 ...
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1answer
3k 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 ...
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1answer
7k 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
551 views

Password prompt before OS is boot

My Macbook previous OS is Mavericks,one day, i use find my iphone to lock my macbook and the Computer started to prompt me enter password(not the lock my mac Firmware password, i removed it right ...
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1answer
857 views

Booting from Windows USB Key Overwrote EFI - Mac No Longer Boots

I'm using a macbook pro running Yosemite. I was trying to create installation media to install linux on an SD card, and I used a USB key that had a bootable windows installation on it. I thought I had ...
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0answers
5k views

rEFIt boot changed after update to Yosemite

I was using rEFIt to work with Ubuntu with my Mac. After the upgrade to Yosemite I had a problem with rEFIt. I found the following solution on ubuntuforums.org but rEFIt still didn't work: cd ...
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1answer
577 views

What's a good graphics card for Yosemite on a Mac Pro 1,1?

I'd like to upgrade my Mac Pro 1,1 (using the EFI workaround hack) to run Yosemite so all my Macs are running the same version of OS X. This old box is only used as an HTPC, so smooth 1080P video ...
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0answers
618 views

Accidentally Removed EFI Partition

I removed the EFI partition accidentally but I have it on a Time machine backup. Is there a way to simply move it from my external drive to my boot drive. I've tried restoring the format of the ...
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3answers
1k views

Can't boot on OS X partition after resizing Windows partition

I initially had three bootable partitions: OS X Recovery for OS X Bootcamp (Windows 8) Now, on Windows, I decided to make my Windows partition smaller, reducing its size using the native Disk ...
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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 ...
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0answers
1k views

How to recover fully formatted EFI partition?

I have macbook 4,1. I tried to install on it ubuntu and fully formatted hard drive. So, there are any way to restore efi partition? (now all apple bootable cd display stop sign and do not work) I ...
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1answer
3k views

How to fix broken GPT, GUID and unmountable and without type volumes?

I have Macbook pro with mavericks and 512GB SSD i accidentally deleted a partition and suddenly my mac could not boot any more and after i tried to do something with disk utility this is gpt -r show ...
1
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1answer
1k views

Understanding firmware.scap

So, I recently acquired an old MacbookPro (v.5,4 mid 2009). I decided to create an Arch linux partition, and thus began my adventure... While installing rEFInd (the maintained fork of rEFIt), I ended ...
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1answer
361 views

Boot menu not working

So basically I can't boot from my ssd anymore. It just shows a grey screen with an error symbol. I can't get into target disk mode and none of the other boot shortcuts seem to be working either. When ...
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1answer
285 views

If I mess up the EFI System Partition, will Mac OS X be unbootable?

I forgot to make a backup of my EFI System Partition (ESP) and have installed grub onto it. If I happen to accidentally mess up the partition, will OS X be bootable? If not, how would I restore the ...