iATKOS | United Kingdom

Hi, I own a late 2013 iMac 21” and have successfully used OCLP to upgrade that to Sequoia.

However, I am now trying to upgrade a 27 inch 2012 iMac, but every-time I click on “EFI boot” when using an OCLP installer usb, and then “Install MacOS Sequoia, the I see the apple logo with a progress bar which then goes into Mac recovery mode. I am unable to choose the disk to actually install from.

I have tried this with multiple different USB sticks, and even made installers of Ventura and Sonoma as well, but same end result. The iMac has an Nvidia GTX 680 and 32GB ram. Have been at this for almost 8 hours now, if anyone has any ideas as to what may be causing it or how I could get it to work I would be endlessly grateful. TIA!