How to use your old iPod as a FireWire rescue disk for vintage Macs

As some of these old PowerPC (and early intel) Macs age, sometimes you’ll find that their optical drives may not be up to snuff and some of these older Macs can’t actually do like most Windows machines and USB boot. If you have a FireWire capable iPod and a FireWire cable for it, however, you’re in luck because they can be used as install disks for old Mac OS versions pretty easily!

WARNING: By doing this you’re going to erase your iPod. Get anything valuable off it FIRST. 

What you’ll need:

  • A Mac with a version of Disk Utility that doesn’t suck ass, preferably (so before El Capitan)
  • A FireWire iPod of the right vintage (more later) 
  • A FireWire iPod cable (this might be harder to find)
  • The install disk you want to use converted into a disk image (or, y’know, just nab one off the internet). can be .iso or .dmg 

On the iPods: There is unfortunately a sort of narrow window of iPods that you’d want to use here. Mostly because I’m going to recommend that you flash mod your iPod if you plan on doing this. Those old drives are close to 20 years old at best, and they’re getting tired. Using it for something intensive like this may just push it over the edge.

The problem is that only 4 iPods can both take a flash mod and work with FireWire, and those are the two generations of mini, and the 4th gen iPod (mono and Photo/Color). The 3rd gen can take the same flash mods that the 4th gens can take, but this kills their ability to use FireWire for data. Not exactly ideal. (And the 1st/2nd gens are bound by the same limitation.)
Also, finding FireWire cables can be a bit of a chore, as official Apple ones can run you a chunk of money on the used market. Buying 3rd party ones is totally valid and that’s the way I’d go with this.
If you’re ready, let’s move on:

Actually doing the thing

The first leg of this can be done on a modern Mac, too, but I find old Disk Utility to be more reliable.
Make sure you have your install disk image ready to go. 
Fire up Disk Utility (Applications > Utilities). You’re presented with this (at least if you’re on pre-El Capitan. It’ll be something similar.)

On the side you can see the built in disk and the iPod connected via FireWire. Ignore that there are two disks, my iPod in this case is already prepared for this kinda stuff.

You’re going to want to click the actual iPod, or in the case the thing that says “119.1 GB Apple Computer…” There should now be a row of tabs along the top part of the right side of the window. Click “Partition” and you should now be seeing this:

If you’re just using this as an install disk and nothing more, go ahead and click the menu under Volume Scheme and select 1 partition.

Optional: If you want to actually run the destination Mac off the iPod (and not just boot the installer), you’re going to want to actually select 2 partitions. You can resize them as you see fit, though I’d only give the partition you plan to put the install disc onto an 8GB size or thereabouts. You can adjust this off to the right, or by dragging the little divider between the partitions.

Caution! On newer versions of Disk Utility, there might be an Options button along the bottom. If so, click it and make sure the partition scheme is set to Apple Partition Map if you’re using this for PowerPC Macs. GUID is only for Intel Macs, and MBR is only for Windows machines. In my case, I’m using OS X 10.3.9 and it defaults to APM.

After that’s done, you should now be seeing one or two partitions listed under the main iPod entry on the left (depending on what route you took).
At this point, go back out to the Finder and open the install disc image. It should now appear on the desktop as an actual disk. If you go back to disk utility, you should be able to see it under the image name:

At this point, everything should be ready to go. Click on any one of the disks, and along the tab bar on the top, click Restore and you’ll be brought here:

This is how we tell Disk Utility that we want to perform a copy of everything from one disk to the other. You want the source to be the mounted install disc, and the destination to be the partition you set aside for the installer. So in my case, it looks like this (with horrible iPad drawings to help, ha.)

(An aside: You COULD just select the image file itself without even mounting it first. However, in my experience this causes Disk Utility to have a conniption fit 80% of the time. I find mounting the disk and using the actual virtual disk as the source instead of the image file to work a LOT better and way more consistently.)

If everything looks good, go ahead and hit the Restore button! And go grab a coffee or something, it’s going to be a minute. 
After it’s all done, you’re finished, and ideally you should have a bootable FireWire disk made out of an iPod!

Booting the destination Mac

In this case I am making an assumption: That the destination Mac is completely without an OS and unable to boot without the help of our little friend here. This is also where the sweet taste of FireWire is required.
You may notice when you disconnect the iPod that it is now very angry; it’ll try to boot and go to the folder icon which means it doesn’t know where the OS is. This is normal. What you’re going to do is just hit the center button to boot it and then quickly hold center and play/pause. This should boot it into disk mode.
(Normally, it’ll automatically kick itself into Disk Mode if you connect it to a computer, but why leave it to chance?)
Once you see the “Ok to Disconnect” screen, plug it into the destination Mac and start it up while holding the Option key. The Mac should show two OS 9-looking buttons: a refresh button and a “go” button. It’ll take a minute or so, but right now the machine is actively looking for drives to boot as evidenced by the mouse cursor being a ticking watch.
Your iPod’s install partition should come up before it’s finished. Once the watch turns into a normal mouse cursor, click the iPod, then click the go button and it should begin booting.
If it doesn’t, or it doesn’t show up, you might have to check your work. Is the disk image you used a known good image? Can this computer even boot the version of Mac OS that you’re using? (Like, for example, my G4 12″ can run Panther, but the original retail 10.3.0 discs and images WILL NOT WORK. I need an installer with 10.3.3 at the very least.)
Past that, I’ve no idea what could go wrong, as I’ve not really run into any issues with this method yet. Knock on wood. Ha.