Install newer OS on Mid 2011 Imac

[MacMan2023]

Hi All,

I've been reading you can easily install a new OS vesion than High Sierra on a MID 2011 Imac. Current spec is
1TB SSD installed, 12GB Ram 2.7Ghz I5 & AMD Radeon HD 6770M 512 MB / Wifi Dongle installed x3 Improved Wifi.

Can anyone answer the following.
1.Can this be done and how complex is it.
2.Is my spec ok to do so - if not what needs improving?
3. Pros and cons of doing so.
4. Can you easily reverse once done if found to be less than a positive move.

Prefer responses from those that have done so, with honest feedback or those very knowledgeable of this.

thanks all

 

[MacsBug]

This isn't that difficult to do. I have not done this on anything older than a 2013, so I am not sure what limitations that the Sandy Bridge processor have vs a Haswell which is on the 2013's

What OpenCore does is use a Boot Picker that will allow the iMac to load unapproved OS's.

You would need to download the OpenCore Legacy Patcher and install it on High Sierra. Create an OS installer using the patcher. then let it Build and Install OpenCore on your iMac. Then reboot and install the new OS.

Also, I like setting it the Boot Picker Timeout to 0 in the settings which needs to be done prior to Building and installing. This will set the iMac to just Boot Directly into the OS. You can still Access the Boot Picker by holding down the Option key at boot and selecting it.

After installing any updates you will need to download the latest version of the OpenCore Legacy Patcher and run the Post-Install Patch.

To go back to High Sierra, and remove the OpenCore Legacy Patcher you would just boot the iMac while holding down the Option key and select the HD with High Sierra on it. This will bypass the boot loader. Then you would mount the EFI partition and delete the files on there.