“Apple usually weeds out a few machines with new versions of OS X, but 10.5 is the first release I’m aware of that will exclude a larger number of machines from being able to run the new OS. For example, my trusty G4 fails to meet the minimum processor requirements — it has enough RAM to run 10.5, but the installer prevents me from installing. I doubt I’ll be alone here,” ‘vorlonwarrior’ reports for macosxhints.
“All is not lost, however, as it is possible to modify the file that checks the machine specs and decides if 10.5 can be installed,” ‘vorlonwarrior’ reports.
The instructions are in the full article here.
MacDailyNews Take: It’s a bit of a convoluted process and not explained in enough detail as Terminal newbies might like, but, as our old (circa 1999) test Power Mac G4 (AGP) 450MHz, yes, 450MHz, with 1GB RAM, attests: it does work. Have you been successful with installing Leopard on unsupported Macs? If so, please, let us know how did you did it below.