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In an attempt to save some space on my ssd, I used SuperDuper to clone Recovery HD to a USB drive. But when I booted up my Mac holding the option key I only got the ssd and Recovery HD as alternatives.

Does anyone have an idea as to how I can clone Recovery HD to an external drive/memory stick and then remove it from the boot drive?

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Does the USB copy show as bootable in startup prefs with an os running? You may have to select it once to `bless the image if SuperDuper didn't. Hit up dave on his support site - he responds well to questions and you know he's playing with the same thing presently. –  bmike Jul 22 '11 at 5:00
    
I tried and it does not. I did not know that he's trying to make the same thing work, but I will contact him. I'll try to get back here if I get any progress. –  andersmoldin Jul 22 '11 at 9:28

3 Answers 3

up vote 6 down vote accepted

The best answer is one supported by Apple.

Why not use the new Lion Recovery Disk Assistant to make your USB bootable media.

The only requirements are listed as:

  • A Mac running OS X Lion with an existing Recovery HD
  • An external USB hard drive or thumb drive with at least 1GB of free space

Detailed, step by step instructions are updated at http://support.apple.com/kb/HT4848

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Voted up. Readers, please note that Apple's assistant will customise where necessary; so a flash drive produced on one computer may be properly unable to boot a different computer running the same version/build of the operating system. –  Graham Perrin Aug 10 '11 at 6:20

Luckily I've done this as a proof of concept. The key is to use the terminal for it. Apple hides the recovery partition by default in Disk Utility which makes it hard to clone. Fire up your terminal and let's get started.

Type diskutil list and find the partition name for Recovery_HD, it should be something like disk0s3

What we're going to do with this is create a disk image with dd and then we can use disk utility to restore it to the usb drive.

Type dd if=/dev/disk0sX of=/Users/USERNAMEHERE/Desktop This creates a disk image copy of the recovery partition in a disk image on your desktop. Note, X is the number that you found from diskutil list

Let dd run and the once you get your prompt back, you can quit terminal.

Open up Disk Utility and find the USB drive you want to clone to. Make sure that you have everything off the drive.

Click on the 'Restore' Tab. Drag your newly created disk image into the Source box, and do the same with your drive into the destination box.

click restore and let it run.

Once it's finished you should be able to boot from this drive, in theory. I would like to note that I had an issue using this drive on a computer that had SL installed, which I find to be a bit odd but YMMV

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I could not get this to work. I get stuck at Disk Utility wanting to scan the USB drive but I only get an error stating: "Unable to scan [drive name] (Invalid argument)". –  andersmoldin Jul 23 '11 at 23:06
    
In that case you may want to use dd again. This time use the arguments dd if=YOUR IMAGE HERE of=SOMETHING FROM THE LIST. if you run diskutil list again with the drive plugged in you should be able to find it's name and then restore to there. let me know if you have trouble finding the name –  cafhacker Jul 25 '11 at 1:58
    
Please be aware that not all Apple_Boot Recovery HD partitions are the same. A partition that's good for one installation of 10.7 (Build 11A511) may be not completely good for another. –  Graham Perrin Aug 2 '11 at 3:46

Caution

Whilst Apple makes it very easy to create a disk/volume from an image (.dmg):

  • if straying from what is recommended by Apple, you should not expect the result to be good for all purposes.

Recommendation

Wait for Apple to provide Lion on a USB thumb drive (announced on the day of Lion's release, scheduled for August 2011).

Background

Experimental uses of .dmg files relating to Lion (burning to USB flash drive, DVD, external hard disk partition etc.) have been publicised by well-meaning hackers since February 2011, and continue to be promoted (not by Apple) without due caution for Mac OS X 10.7 (Build 11A511). Bootable media produced in this way may be good for some uses but please, proceed with caution: other uses may leave a system unusable.

Be aware of the known risks, and unknowns, associated with straying from what is recommended by Apple. Consider this recent conversation in Ask Different Chat:

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This is awesome as a reference, but I've got to put my stock in the Official Tool now that it's out :-) –  bmike Aug 9 '11 at 20:32
    
In addition to the vote down, it will help readers to know why it was voted down. The intention is to help users avoid a system that is unusable; how can that intention be voted down? –  Graham Perrin Aug 10 '11 at 4:41

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