Installing Mac OS Lion On My Mac Mini – The Hard Way

Yesterday I told the story of how I wound up having to put a new hard drive in one of my Mac mini systems and, thanks to that, also reinstall Mac OS so the computer would be usable. After an entire night of messing with the system and figuring out just what had gone on, replacing the dead hard drive, then reinstalling older versions of Mac OS the system was ready once I awoke Monday morning for me to install Lion; the most recent version of Mac OS that the system supported, and one perfectly fine for what I feel I would use the system for. I didn’t do this last night as the install files were stored on a computer I wasn’t about to boot up in the middle of the night in another room of the house — it was better to just wait till morning.

Once I awoke I took the machine into the living room where my Mac Pro and my new “office” setup is. Given these machines have Firewire ports — in this case Firewire 400 on the Mac mini — I was about to do something very similar to what I did a year ago with my PowerBook G4: Set up a partition on the hard drive which would allow me to install Lion without issue. Or, at least, I thought it would be without much issue; that wouldn’t be the case, as you’ll soon read.

By booting the machine into target disk mode I could access the hard drive directly on the Mac mini (I mentioned details on this process in the last article) and edit the partitions to create the “restore” drive, so to speak. Again, this is much like what I did on the PowerBook G4 last year. Boot the machine, select this new partition, and install the operating system from that partition onto the main partition, then eventually delete the old partition and have the full space of the hard drive available to use. Easy, right?

Wrong. The problem is the way Mac OS Lion and later Mac OS versions were distributed. Up until Snow Leopard all Mac OS X versions were distributed on typical CD’s or DVD sets which you could boot from to install with. This is what I did the other night to get Leopard and Snow Leopard on that Mac mini. Lion, however, marked the first Mac OS upgrade released via the App Store, meaning there is no disc available. Additionally, the installer likes to be a bit fussy, thanks to it being digitally signed as a package as opposed to just being a normal program which runs. Go figure.

This is the part where I fully admit my copy of Lion isn’t legitimate — it’s a download I’ve used for the past few years, and while (for some reason) I had no issue upgrading this Mac mini to Lion before, this time around it was being a pain in the ass thanks to those digital signatures — setting my clock to around the time of Lion’s release (a common tactic with most later MacOS versions to get them to install without complaining) didn’t work.I tried to use a program to make an installer onto the spare partition I had created, but this went to no effect. For whatever reason, Lion.app just wasn’t having it. Again, I figure this due to the digital signature on the app which, in retrospect, I could probably have checked details on, but didn’t think about it at the time. I was stuck in the water, so to speak, unable to install via the usual method. I’d have to try another option and, having already tried various tools to make USB installers, all of which also failed, I began to get somewhat desperate. It worked before, why wouldn’t it work now? I had to have an answer and began hunting online, intending to find a solution. I found one, but not the one I expected.

In scouring the web I found an interesting little tidbit of info, though, which I’ll go into in detail in a future article. The Lion installer app is just that – an application which creates an installer for the operating system. Like any .app file in MacOS, it’s actually, in a sense, a folder containing the files which make up the program in question. One of those files, buried deep in the app, is basically a disk image identical to an older Mac OS install disc, and that disk image was what I extracted and installed on the partition of the Mac OS hard drive.

With that, Lion was ready to go. I don’t understand why the various methods I had tried before didn’t work — perhaps this was another version of Lion I had downloaded, and my original install was a different copy of the installer? Who knows, but I got the job done and my clean install of Lion is working a treat, for what it is, anyway. I still am not using the machine for much, I just like knowing it’s good to go for a little early 2010’s Mac goodness. That, and one very special task I’ll write about soon enough.

More to come, as always.