If what you have is a genuine iPad and your friend took it from the factory before the OS was loaded, it's stolen. Period.
So what if it's stolen? The Chinese people are making our ipads, and yet you still wouldn't understand that they are the ones who deserves to use it. Just like us.
If you know your friend ...
Linux? no... Darwin or Mach, maybe...Acitivating a no os ipad can only be done if you know a lot about linux sourche code..