Well here is what I did and it worked perfect... But in my case I have a Mac mini late 2006...
Don't use the latest macpostfactor tool 2.0.1 I believe.... I used that one first and for some odd reason everything worked good except I had no graphics acceleration... But I saw a video of dosdude1 installing OS X ML on the Mac mini running perfectly... Because ML was the last system that they were able to bundle a Developer release of ML that allowed 32bit kexts to load, because if you install Mavericks or Yosemite in my case in the Mac mini you lose wifi and graphics acceleration, because there are no 64bit kexts for graphics, at least any that work for that matter, so for me in my case I could live without wifi but no graphics is a deal breaker for me, you can't watch videos...
So what I did is, I downloaded the version that dosdude1 used on his youtube video which was Macpostfactor 1.0, went on my regular Mac on macOS Sierra with SIP disabled and used Macpostfactor to create an installer on a pendrive, ran that sucker on my Mac mini and boom! Everthing is running like butter...
It is sad to see that people stoped working on these old Macs... But even on OS X ML on my Mac mini, flashed from 1.1 to 2.1, with an sad and 4 gb of ram is still a very usable adorable tiny little beautiful machine, I can still even iMessage from it
Hope it helps