What is OpenCore Legacy Patcher, and how does it work?

#Layer 1: OpenCore, the bootloader

OpenCore is an open-source bootloader by Acidanthera, originally written for Hackintoshes. OCLP uses it on real Macs and writes its configuration for you. It does four jobs:

1. Reports a supported model. macOS installers check the Mac's model and board ID and refuse to run on dropped models. OpenCore can present a newer, supported board ID while keeping your real hardware. OCLP's settings call this SMBIOS spoofing, with Minimal, Moderate and Advanced levels.
2. Loads kexts. Kernel extensions are drivers. OCLP adds Acidanthera's Lilu framework and plugins (WhateverGreen for graphics, RestrictEvents, CryptexFixup…) and its own kexts for things like Wi-Fi.
3. Patches the boot. Settings such as relaxed System Integrity Protection and boot arguments are applied every time macOS starts.
4. Shows a boot picker. The OpenCore boot picker lets you choose macOS, installers, Recovery and Windows.

A real example: OpenCore for a 2012 MacBook Pro

This is the start of the log from our build with the OCLP 3.0.0-rc.5 app, command line --build --model MacBookPro9,2, on a GitHub macOS runner. Every line names something OCLP puts in the EFI folder for that Mac:

- Using custom model: MacBookPro9,2
Building Configuration for external: MacBookPro9,2
- Adding OpenCore v1.0.6 RELEASE
- Adding config.plist for OpenCore
- Adding Lilu.kext 1.7.2
- Enabling Rosetta Cryptex support in Ventura
- Adding CryptexFixup.kext 1.0.5
- Enabling legacy power management support
- Adding AppleIntelCPUPowerManagement.kext 1.0.0
- Enabling macOS 26 FileVault 2 support
- Enabling BCM943224 and BCM94331 Networking Support
- Adding AirportBrcmFixup.kext 2.2.1
- Adding IOSkywalkFamily.kext 1.2.0
- Adding IO80211FamilyLegacy.kext 1.0.0
- Adding AirPortBrcmNIC-Tahoe.kext 1.0.0
- Fixing Legacy Bluetooth for macOS Monterey
- Adding BlueToolFixup.kext 2.7.2
- Enabling Board ID exemption patch
- Disabling AMFI
- Adding AMFIPass.kext 1.4.1
- Fixing CoreGraphics support on Ivy Bridge
- Adding RestrictEvents.kext 1.1.7
- Adding AppleUSBTopCase.kext 1.0.0

The model pages show this list for every supported Mac (under “What OCLP puts on the EFI partition”), from the same runs.

#Layer 2: root patches

Booting is not enough. Apple deletes the drivers for hardware it drops: Intel HD 4000 graphics left with Monterey, NVIDIA Kepler with Monterey, older Broadcom Wi-Fi with Sonoma, and on Tahoe even the audio driver. Without them, macOS runs but without graphics acceleration, Wi-Fi or sound.

Root patches copy those drivers (and some frameworks) back onto the system volume, taken from older macOS versions and maintained in Dortania's PatcherSupportPkg (2.0.5 in OCLP 3.0.0). macOS seals its system volume, so OCLP mounts it, adds the files, rebuilds the kernel cache and creates a new snapshot. That is also why macOS updates remove them: an update replaces the whole system volume.

Which patch sets your Mac gets depends on its GPU, Wi-Fi card and macOS version. There are 21 of them; see Root patching for the full list.

#From Big Sur to Tahoe

#Is OCLP a Hackintosh?

No. A Hackintosh runs macOS on a PC that Apple never made, which Apple's license does not allow. OCLP runs only on real Macs, which is why it can rely on Apple's own firmware and drivers. They share a tool, OpenCore, and some of its developers, but the goal and the hardware are different. If you came here for a PC, the right resource is Dortania's separate OpenCore Install Guide, not OCLP.

#Who makes it

Dortania, an open-source group. Main co-authors: Mykola Grymalyuk (khronokernel) and DhinakG. The Tahoe, non-Metal and Metal patch sets are largely the work of EduCovas and ASentientBot; recent releases also credit Jazzzny and crystall1nedev. OpenCore and the Lilu kexts come from Acidanthera (vit9696 and others). We are not part of the project; see About.

#Common questions

Something wrong or out of date on this page? Email hello@oclp.dev and we will fix it (see our corrections policy).