Help with iMac 2015 (A1418) Firmware Issues - Seeking macOS Equivalent of Linux "noapic maxcpus=3"

Hi everyone,

I’m working on a Late 2015 21.5" iMac (A1418 / iMac16,1) that has significant firmware/hardware instability. I am trying to get it running with OpenCore Legacy Patcher, but I’m hitting a wall during the boot process.

The Problem: This machine has a known firmware/CPU issue. On Linux (Pop!_OS/Ubuntu?Fedora does not matter which bistro I use), the only way it will stay stable is by using the boot parameters noapic and maxcpus=3. Without these, it freezes or kernel panics immediately.

What I've Done So Far:

1. Created a macOS Monterey installer via OCLP on a separate Mac.
2. Manually edited the config.plist via Linux to add cpus=3 and -v to the boot-args.
3. Verified the edit is active (I can see the verbose text scrolling).

The Current Hang: Even with cpus=3, the macOS boot freezes. It consistently hangs at AppleUserHIDDrivers or displays a massive wall of com.apple.xpc.launchd failed lookup errors. The last few lines usually mention port is not ready for callouts.

My Questions:

• What is the best way to replicate the noapic fix in OpenCore?
• Is there anything else I should add to boot-args to bypass power management states that might be triggering the firmware fault?

Any help from the OCLP experts would be greatly appreciated!