🖥️ This should be easy, right??

I was asked to get a 2013 14,2 27" iMac setup so that it was usable in 2025… it’s an Apple computer - this should be easy, right???

Well - no. I tried the simple stuff first; clicked the Apple logo in the upper-left corner of macOS, clicked ‘About this Mac’ and tried to run updates. That got me a handful of application and security updates - but nothing for macOS. Come to find out, the 2013 iMac had macOS 10.9 Mavericks installed…

Ok, ok - no big deal; this is an Intel Apple machine so let’s reboot and hold option+command+R to get into Apple’s Internet Recovery… however, doing so didn’t yield a macOS Catalina (the last supported macOS for these 14,2 iMacs) installation - just Mavericks. Well, let’s boot into Mavericks and open the Apple Store - I can surely find macOS Catalina there, right???

You know the story; there was no support ON this iMac to get it updated in 2025. Well, I thought I’d just burn a macOS Catalina .ISO and get on with things - hold option at boot, and then select the Catalina EFI USB Stick… but when it came time to check for compatibility, the macOS Catalina installer refused to install!

We’re gonna have to bring out the big guns…

📀 Get to Catalina…

The first issue will be getting the 2013 14,2 iMac to its highest supported macOS version - Catalina. Since Mavericks refused to recieve a Catalina install, I did some research. I thought I could use OpenCore Legacy Patcher to take this iMac beyond Catalina and noticed that even it needed at least macOS 10.10 Yosemite… so maybe if I update Mavericks to Yosemite I’ll be able to get to Catalina.

I was able to download macOS 10.10 Yosemite as a .dmg file directly from Apple Support. I actually preferred to download with wget in my terminal:

wget http://updates-http.cdn-apple.com/2019/cert/061-41343-20191023-02465f92-3ab5-4c92-b
fe2-b725447a070d/InstallMacOSX.dmg

After which, I copied that .dmg file to a USB stick, ran it on the iMac 14,2 running macOS Mavericks - and Bob’s yer Uncle!! I had macOS 10.10 Yosemite up and running!!

Now, when I opened the Apple Store in Yosemite I could search for ‘macOS Catalina’ and see it… but I’ll be darned if it wasn’t a click and install solution - but we hinted at the macOS Catalina .ISO before, so I downloaded it and burned the ‘MacOS Catalina ISO 10.15.7.iso’ with Balena Etcher and went back to the 2013 iMac… hold option at boot, and select the Catalina EFI USB Stick.

… the macOS Catalina install took around an hour, but at the end I had a completely stock macOS Catalina installed and working on the 14,2 iMac!!! Yay!!!

💭 … but we can do better?

This was great - I could deliver the iMac and the user would get a full ‘brand new’ experience; they’d be greeted with macOS’ setup process and the world is great, ya?

We’re overachievers here - let’s force an even later version of macOS that might give the user more ‘current day’ OS and software; I’ll take one small step that preserves THIS macOS Catalina setup, tho… since WiFi doesn’t work out-of-the-box on Linux distros, I lugged the iMac to my router and plugged it into my home network. I booted Rescuezilla and made a backup of the Catalina iMac that I could burn for the user in case they ever wanted to revert to the last ‘supported’ macOS… who knows, maybe the user will find some issues or bugs with what we’re about to do next!! NOTE: We actually had to make backups of two disks - a 113GB SSD and a 931.5GB HDD. Apple shipped some machines with a ‘Fusion drive’ that are actually two different disks - macOS’es firmware fuses them - its a good idea to jot down the contents of:

diskutil list
diskutil info /

In case we ever need to restore - this info will help us if there are any issues with the Fusion drive not lining back up - but hopefully wouldn’t be needed.

🚀 Going beyond Apple’s walled garden!

OLCP, baby - OpenCore Legacy Patcher

The OLCP documentation states that I could go up to macOS Sequoia, Apple’s most current OS, but I think the user might experience more issues as I know it was slow even on a late-2017 iMac I installed Sequoia on… I decided on macOS Monterey as a good balance of featues; completely modern web browsing, better FaceTime integration and solid performance for the 2013 14,2 iMac - if you decide to go higher than macOS 12 Monterey, please let me know your experience on this 2013 iMac… :P

We pop over to Catalina that’s currently installed, and download and install OLCP. Open the app and from here we can choose ‘Create macOS Installer’ - we’ll be able to select and download a version of macOS that we’re targeting. As mentioned earlier, we’re not going with the newest Sequoia for our 2013 14,2 iMac; we’re going to target macOS Monterey. Select it, download it and choose a 32GB+ USB Stick to install it onto… let OCLP do it’s thing before we move on.

When OLCP is finished burning the USB Stick, you’ll see a ‘Sucessfully created a macOS installer! You can now install OpenCore onto this drive’. What that means is the macOS USB installer needs OpenCore to be able to boot properly on our non-supported 2013 14,2 iMac… now we’ll select ‘Build and Install OpenCore’ and choose our USB Stick when prompted. (After we install and test, we’ll come back and Build and Install OpenCore on our actual iMac Fusion drive.

Insert the macOS USB installer w/ OpenCore and boot the iMac - hold down the option key; select the EFI USB Stick, and you’ll see the ‘Install macOS Monterey’ icon. Select it and install Monterey!! While it takes a long time, macOS Monterey will install itself nicely… w0w, we’re doing things!!

After Monterey is installed, it will reboot - and you’ll go thru the initial setup process… then OCLP will ask you if you want to install the patch to your local HDD - and gosh darnit, we do!! Accept - and click ‘Install to disk’… you’ll now select your Fusion drive - and gosh darnit, we’re close to being finished!!! Click ‘Reboot to apply’ - and we’re just about wrapped up!!!

… awesomesauce - we have our OCLP shim booting the computer into macOS Monterey on our 2013 14,2 iMac - and it JUST W0RKS!

LAST THING - Don’t forget to do Root Patching in OCLP - but you’ve been following along with the OCLP Documentation, right?!?!

Listen, folks - we brought this old 2013 iMac back into the current times… for a moment, anyway - in a few years we might have to switch over to elementaryOS or Ubuntu - but for the time being we can deliver this machine to our new girlfriend; hopefully she’ll make many paintings while opening a .JPG/.PNG or even GIMP - do I need to explain installing brew.sh to you??? I think not…

TechHeart OUT!

TechHeart.life