Can't boot off USB drive in OS X 10.6.8

Question

I'm trying to boot off of a thumb drive which has an OS X recovery image but am unable to get it to be recognized.

I'm pretty sure the USB stick is written correctly (GUID partition table, Mac OS Journaled file system, etc). I created it through the Restore menu in Disk Utility. It mounts exactly as my original disk did (I would normally use my Snow Leopard disk but I recently moved and am unable to find it).

When I open up the 'startup disk' menu in the settings, I noticed my only options are Network Boot and my current hard drive.

How can I get it back so I can boot off of the USB drive?

Solution

Had a similar problem. I could resolve this by manually setting the boot device using the bless command. This will set a NVRAM variable specifying the device you want EFI to boot from.

sudo bless -mount /Volumes/MyBootVolume -setBoot

Now just reboot with the drive still connected. Note that if you boot without the drive, EFI will pause for several seconds with a grey screen before it continues booting from the internal drive. So you might want to change back the NVRAM variable after you are done. In my case I just deleted the variable completely, because it wasn't present before.

sudo nvram -d efi-boot-device

Your mileage might vary on that, so I would advice to check the original setting before messing with it, either with nvram -p or bless -getBoot.

Comments

[slhck]

How exactly did you create it?

[devnill]

In disk utility I went to the restore tab on the thumb drive and used the wizard to write the image to the disk. It mounts exactly as my original disk did (I would normally use my snow leopard disk but I recently moved and am unable to find it)

[slhck]

You can try holding option, as schuluchc already mentioned, but I'd try to use a different USB drive, or possibly try with an external hard drive (it would only need to be a small partition).

[Canadian Luke]

I assume it was direct from the dvd. I have had people come in with problems similar to this, but using other methods to get an image

[devnill]

After I couldn't get it to boot holding c, I tried this; The only bootable volume is the hard drive itself.