[Sequoia 15.1.1_OCLP2.2] iMac 11,1 (2009) black screen

iMac 11,1 (Late 2009, 27”) • Graphics: ATI Radeon HD 4850 • Storage: 250GB SSD (replaced) • RAM: 4GB (2×2 GB 1066MHz SO-DIMM DDR3)

Hi,

I’ve been researching this issue for quite some time and hope to gain some insights or solutions from the community.

I acquired this secondhand iMac, which retains all stock components except for the hard disk, which has been replaced with a 250GB SSD.

The Issue:

I installed macOS Sequoia 15.1.1 following the standard procedures of OpenCore Legacy Patcher (OCLP). I’ve tried using older versions of OCLP and even the latest 2.2.0; all lead to the same result—booting to a black screen. This issue only occurs after the post-installation patches are applied. After several reboots, it gets stuck at the Apple logo progress bar with only a small portion filled, and it remains stuck for over two days.

Consequently, I forcibly shut it down, boot into recovery, and execute the “last sealed snapshot” command to remove the patches. I can boot into safe mode without the patches, complete the setup, and reach the Home Screen. However, whenever I install the post-installation patches and reboot, it first boots into the boot selector. After selecting the boot disk, it proceeds to the progress bar screen, loading about one-third before suddenly turning to a black screen with backlight. Interestingly, even with the black screen, the iMac’s display turns off (no backlight) after a while and reactivates when I press any key on the keyboard or click the trackpad (both connected via USB).

Previously, I installed Sequoia on a few unsupported Macs. I created the bootable USB for this iMac 11,1 (2009) using another iMac 15,2 (2014). I’m not sure if this information is relevant, but I’m providing specifics to help diagnose the issue.

Any ideas, insights, or suggestions are appreciated and would be invaluable—not just for fixing this Mac, but also for enhancing my understanding of how OCLP and its configurations work.

Thank you for your time and assistance!

submitted by /u/GoldPortal
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