Installing OSX on older/unsupported Mac

If you have an older Mac and would like to upgrade to newer OSX, it can be done via Open Core Legacy Patcher:

I've successfully upgraded a 2009 Macbook (5,2) with 4GB RAM & SSD to OSX Monterey. It required jumping through multiple hoops to make it work (I could write a 2-3 page instruction on this). It runs OK, a bit sluggish starting apps. I think If you have an older (2007-2011) Mac with 4GB RAM and USB 1.1, it'd be easier to install Linux Mint instead -- you'll have access to the latest security updates and linux apps.

If you have a 2012+ Mac, you'd jump through fewer hoops. Preferably you should have SSD and 8GB RAM to go beyond Monterey, which is supported until Nov 30, 2024 by Apple. I might upgrade a 2013 21.5" iMac to Sonoma later.

OpenCore is amazing! I have a 2012 Mac Mini (I upgraded the RAM and changed to SSD years ago) on it and it is still running great with Sequoia.

zovall said:

OpenCore is amazing! I have a 2012 Mac Mini (I upgraded the RAM and changed to SSD years ago) on it and it is still running great with Sequoia.

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You have the good fortune of being able to upgrade to 2x8GB DDR3 RAM for $16.

My 2009 MacBook could take 2x4GB DDR2 after BIOS update, but the RAM cost $50 and it's not worth it.

For the 2013 21.5" iMac, it came with 8GB RAM installed and after viewing the RAM upgrade video, I think I'll upgrade the SSD only.


Sequoia will be the last OSX that supports Intel. I think Apple will support Sequoia with updates until late 2027. Afterwards it's probably the end of the intel hackintosh era.

Just installed OSX Sonoma on my in-law's late 2013 21.5" iMac.

The iMac has an old 1TB internal HDD that runs like a slug, I decided to be lazy like the slug and use an external SSD instead of upgrading the internal drive. This actually caused more trouble with installing OSX via OpenCore.

You can get the Sabrent external SSD enclosure (EC-UASP) that supports UASP mode for $11 at Micro Center. Plug a $50 Samsung 500GB SSD in it, hook it up and run Apple recovery mode to download and install latest supported OSX to the external SSD. For the 2013 iMac, it ran Catalina very well. You hardly notice that it's running from an external drive. But I cannot verify it's running in UASP mode.

Unfortunately, most recent software (including HP printer setup/drivers, latest Google chrome, etc.) require Big Sur or Monterey and higher. So I installed OpenCore Legacy Patcher and made a bootable Sonoma install USB.

Lo and behold, when you try to boot with both the external SSD boot drive and the bootable USB stick... it won't work (they won't show up on the boot menu). You must disconnect (or turn off) the external SSD, boot with the USB stick, then turn on the external SSD.

Since the Sonoma install process requires like 5 reboots, you can imagine the trouble it caused. Turn off SSD, boot from USB, turn on SSD, proceed with install, rinse and reboot 5x.

This could be avoided if you actually go through the trouble of prying open the iMac and replacing the internal drive with SSD. It would have made things easier and get better performance out of the SSD upgrade.

How well does the 2013 iMac run Sonoma? Not as snappy as Catalina, but still much faster than the internal HDD. Restored about 80GB of data from time machine backup via migration assistant and it went well. Running Black magic disk speed test, the read/write speed is about 420 MB/sec, which is acceptable for external 2.5" SSD via USB 3.