sean's place

Leopard on Old Hardware

Apple, in their infinite wisdom (read: desire not to create a lousy user experience), enforces the advertised minimum system requirements in the Leopard installer. I found this frustrating, because I don’t mind changing off of a lousy experience, if it happens to actually be lousy.It turns out, however, with a little engineering know-how, one can bypass the restrictions. The folks over at Mac OS X hints describe the procedure.I made the following modifications to the guide because I didn’t any luck booting off a second partition (and don’t have a working external drive):

1. Create a partition for the Leopard packages and installer on my main drive. Leopard’s Disk Utility can resize partitions and can be run from the install DVD. I named the volume Leopard Install
2. Copy /System/Installation to the new partition.

   # cp -Rp "/Volumes/Mac OS X Install DVD/System/Installation" \
   "/Volumes/Leopard Install"

3. Adjust the OSInstall.mpkg as described in the above link. Roughly:

   # cd "/Volumes/Leopard Install/System/Installation/Packages"
   # mkdir OSInstall
   # xar -x -f ../OSInstall.mpkg

4. Edit the Distribution file. Find the JavaScript function that checks for minimum hardware and either alter it or remove the contents and have it simply ‘return true;’.
5. Recreate the OSInstall.mpkg file:

   # xar -c -f ../OSInstall.mpkg *

6. Boot the Leopard install DVD.
7. After the installer fails, open Terminal and find the installer process.

   # ps auxw | grep Install

8. Copy the command line (should contain something like Mac OS X Installer and not LCA) into the clipboard. Then kill the matching processes.
9. Overlay your hijacked installation files:

   # mount -t hfs /dev/disk0s5 /System/Installation

10. Restart installation by re-executing the command in your clipboard buffer.

This worked for me… it took a few tries, but it worked. Probably time to revert back to Tiger on the laptop though, Leopard seems a little too sluggish for my taste.