Strange "EFI Boot" option at startup

Question

Strange "EFI Boot" option at startup

When I hold down option after restarting my iMac, I get a list of boot options. In addition to my normal boot partition and Lion's Recovery HD, I also have 2 other bootable partitions: "Clone Partition" and "Maintenance Partition". These are all expected as I have OS X installed on each one.

I also have a "Time Machine Partition" on my internal drive, to which Time Machine backs up. (I know, TM should backup to an external drive. But I backup to an external drive using Retrospect and SuperDuper for now.) The Time Machine partition shouldn't appear as a boot option and it doesn't.

Now, here's the strange thing. When I restart and hold down option, I see the expected boot options but I also have an extra boot option. It's called "EFI Boot" and its icon is the Time Machine drive icon. If I select EFI Boot as my boot option, it appears I end up booting with Recovery HD because I end up with the Recovery HD desktop.

Using diskutil list in the Terminal, I see EFI is a 209MB partition with identifier disk0.

Why is EFI Boot appearing when I hold down option at restart? Why does it "link" to Recovery HD? How can I keep it from appearing as a boot option? It's merely cosmetic, I suppose, but I'd feel better if I could fix this abberation.

Thanks.

iMac (24-inch Early 2009), Mac OS X (10.7.3)

Posted on Apr 17, 2012 9:14 PM

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Answer 1

Apr 17, 2012 9:38 PM in response to Kappy

Hello Kappy. I think that was the fastest reply I've ever received! 🙂

Thank you also, Linc Davis.

As a point of comparison, my wife has a MacBook Pro. On the internal drive she has a Lion installation and another partition containing her Time Machine backups, like me. If she holds down option at startup, her boot options are:

MacBook Pro HD
Recovery HD
Time Machine Partition

In my case, it appears the "Time Machine Partition" is renamed "EFI Boot". Is there some way I can get "Time Machine Partition" to appear instead of the cryptic "EFI Boot"?

I found an Apple Discussions thread that talks about using the bless command in Terminal to correct a similar problem, but I'm not sure if that applies here.

Also, just to verify I understand this correctly: When I choose EFI Boot as my boot option, the Recovery HD installation that I'm booting into resides on the Time Machine partition?

Thanks again to you both.

Message was edited by: Anthony M Kassir MD

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Answer 2

Kappy

Level 10

362,017 points

Apr 17, 2012 9:22 PM in response to Anthony M Kassir MD

Time Machine in Lion 10.7.2 and later now makes an invisible copy of the Recovery HD, so that if needs be you can boot the computer from the Recovery HD image stored on your Time Machine backup drive. EFI Boot is how it is identified in the boot manager. This is not specifically related to the small EFI partition on the hard drive because OS X does not use that partition for anything presently. However, do not attempt to modify or remove it. Consequently, there is no abberation. All is as it should be.

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Answer 3

Kappy

Level 10

362,017 points

Apr 18, 2012 8:44 AM in response to Anthony M Kassir MD

I have no explanation as to why the difference between the two. Technically, yours should also read Time Machine Partition, I believe, but I've seen this same thing happen on my systems with all sorts of mixed system volumes where some read "EFI Boot" rather than the actual volume name. It's something I cannot explain but that is not a problem in and of itself.

Nevertheless, if you select that volume then you will indeed be booting the Recovery HD image stored in your Time Machine backup. But, there's no reason to use it except if you have no other way to start up the computer. Normal way to boot the Recovery HD is to use the COMMAND and R keys at startup to boot the one that is on your system drive.

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Answer 4

Linc Davis

Level 10

209,739 points

Apr 17, 2012 9:22 PM in response to Anthony M Kassir MD

Normal. The Time Machine drive is bootable into Lion Recovery. That's what "EFI Boot" is.

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Answer 5

Shootist007

Level 6

16,709 points

Apr 18, 2012 9:32 AM in response to Anthony M Kassir MD

Actually with Lion and the newest TM program it will create a Recovery HD section on the TM disk so you can boot from it. That may be one of the Boot options you are seeing.

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Answer 6

Kappy

Level 10

362,017 points

Apr 18, 2012 9:44 AM in response to Shootist007

i think this has already been covered here, don't you? 😕

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