Setting up Ubuntu on an older iMac

What does one do with a Core 2 Duo iMac that only has one gig of RAM? OSX Lion requires at least 2 gigs of RAM, and older version of OSX are hard to come by, legally that is.  I decided that the best thing to do with an  (almost) junker machine was to install Ubuntu.

I acquired this Mac from a friend under the terms: "If you can fix it, you can keep it."  The machine needed a logic board replacement for starters, as it wouldn't boot.  I came across a replacement on eBay for the low price of $20.  Once I had that up and running, I grabbed my trusty OCZ Vertex 2 SSD from my desktop and slapped it in the Mac (Why not, I had it open anyway).

Read the install instructions after the break.


Keep in mind that this guide is for single booting Ubuntu on iMac hardware.

1. Acquire the correct installation media.  Use the "+mac" edition ISOs.  Ubuntu 12.04.2 media can be found here. 
2. Make yourself a bootable DVD or USB key.  I made a DVD myself as I had trouble getting the iMac to boot from USB. Instructions
3. Plug in the new disk or flash drive and power up the Mac.  Hold down the "C" key to boot from external media. (If this doesn't work, try using the boot manager screen by holding the Alt / Option key when booting).
4. Run through the normal Ubuntu install. Make a standard BIOS/MBR  partitioning scheme.  No need for GPT/EFI  magic here.
5. Remove media and reboot. (Cross your fingers.) Be patient.  You may be looking at a white screen for over 30 seconds. We will fix this later.

The following steps are optional.  This procedure will remove the 30 second wait before grub loads.  You will need an OSX install disk (the version doesn't matter).

1. Open terminal and type: gksudo gedit /etc/default/grub
2. The file should look like this.  Add the following line: GRUB_PRELOAD_MODULES="ohci usb_keyboard"
3. Rebuild grub with the following command: sudo grub-mkconfig -o /boot/grub/grub.cfg
4. Reboot again, this time insert and boot from the OSX install disk using the same method as before.
5. Once the installer loads, close the little box, and open Terminal from the Utilities menu.
6. Type: bless --device /dev/disk0s1 --setBoot --legacy ,where /dev/disk0s1 is the partition you installed grub onto. (If you still get the 30 second white screen, try running the command again for a different partition, say /dev/disk0s2.)
7. Reboot again. Hopefully this time your Mac boots into Ubuntu right away.  

That's all I've got right now.  Later I will get a Wifi working and post a tutorial on how to do that.