Can't boot from external USB DVD drive

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Level 2

276 points

Can't boot from external USB DVD drive

I need to boot my OSX 10.5 install DVD from an external (USB) DVD drive. (Disk Utility says my hard drive needs some minor repairs, which requires booting from another device, but the internal DVD drive in my iMac is broken.)

I bought a Toshiba "Portable SuperMulti Drive" (model PA3834-U-1DV2) for this purpose. If I insert the install DVD in the drive, it spins up and appears as an icon on the desktop. Further, I can open it and the files it contains. So it seems to be working, but I can't boot from it.

I've tried restarting while holding down C and while holding down Option. (The latter action offers me only my hard drive as a boot volume -- the DVD doesn't appear.) I've also tried selecting the DVD as the boot volume using System Prefs/Startup Volume, but the DVD doesn't show up as an option there, either.

So I can read from (and presumably write to) this external DVD drive, but can't boot from it. Is this a common problem with external USB DVD drives, or possibly unique to my Toshiba?

iMac G4 20" USB 2.0, 1.25 GHz 1.5/160 GB, Mac OS X (10.5.8), AE 5.7, AX 6.3, AE card 405.1 (all b/g)

Posted on Sep 15, 2010 8:41 AM

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Answer 1

a brody

Level 10

85,314 points

Sep 15, 2010 9:19 AM in response to Dave Post

USB drives can't boot Mac OS X on PowerPC Macs.

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Answer 2

a brody

Level 10

85,314 points

Sep 15, 2010 9:23 AM in response to a brody

That said:

1. Firewire drives can boot PowerPC Macs that support Target Disk Mode.

2. USB drives can boot Intel Macs (these are ones that also support Snow Leopard installation).

3. USB drives can boot Macs into Mac OS 9, which support booting into Mac OS 9.

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Answer 3

Dave Post Author

Level 2

276 points

Sep 15, 2010 10:18 PM in response to a brody

Thanks very much for your swift and authoritative replies.

USB drives can't boot Mac OS X on PowerPC Macs.

It would have been nice if the Help system had mentioned that point, especially because Firewire drives seem uncommon these days. Help tells me only that I can boot from an external DVD drive.

Fortunately, my G4 supports Target Disk Mode, so I've returned the Toshiba and am seeking a Firewire 400 replacement. Presumably, that will solve my problem.

Thanks again.

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Answer 4

Courcoul

Level 6

18,684 points

Sep 15, 2010 10:23 PM in response to Dave Post

If you know someone with a Mac, then the only thing you need is a Firewire cable compatible with both (FW400 to FW400, FW800 to FW800 or FW400 to FW800). Start up the sick Mac in Target Disk Mode, plug to the other Mac, which will see the sick Mac as an external drive so you can use Disk Utility or whatever other tools you want to repair it.

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Answer 5

Dave Post Author

Level 2

276 points

Sep 15, 2010 10:44 PM in response to Courcoul

Excellent idea. Just be sure the app on the host machine is compatible.

In my case, for example, I also own a G3 running 10.3.9 (that's as far as it can go), but its older version of Disk Utility reports the G4's hard drive is fine! So I'd do best to borrow a Mac running 10.5.8, just like I'm using now on the G4. (Not sure a 10.6 version could be trusted or an earlier 10.5 version would work.)

I'll see if I can follow your suggestion. It's obviously cheaper, especially because this will (hopefully) be a one-time-only need.

Thanks!

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