# Explaining the patches in OpenCore Legacy Patcher

In our patcher, there are numerous patches used to ensure a stable system. Here we're going to go over what patches are used and why we recommend or even require them.

# OpenCore Settings

Below is a run down of the main logic OpenCore Legacy Patcher uses to gain native support in macOS. Note OpenCore's configuration is documented within OpenCorePkg (opens new window) as well as an online version provided by us:

Configuration Explanation

# ACPI -> Patch

  • EHCx and XHC1 Patches
    • Reason: Required for proper USB operation
    • Logic: Avoids USB maps of newer models attaching and breaking USB port functionality
    • Models: All models require when spoofing with Moderate or Advanced SMBIOS

# Booter -> Quirks

  • ForceBooterSignature
    • Reason: Required to ensure Hibernation support
    • Logic: Tricks boot.efi into thinking OpenCore is Apple's firmware
    • Models: All models require

# DeviceProperties -> Add

  • PciRoot(0x0)/Pci(0x15,0x0)/Pci(0x0,0x0)
  • PciRoot(0x0)/Pci(0x1C,0x4)/Pci(0x0,0x0)
  • PciRoot(0x0)/Pci(0x1C,0x3)/Pci(0x0,0x0)
  • PciRoot(0x0)/Pci(0x1C,0x5)/Pci(0x0,0x0)
  • PciRoot(0x0)/Pci(0x1C,0x1)/Pci(0x0,0x0)
    • Reason: Required to ensure Wifi works with full, native support
    • Logic: Tricks AirPortBrcmNIC.kext into thinking our device is a BCM94360 (14e4,43ba)
    • Models: Machines with BCM943224 and BCM94331 chipsets
  • PciRoot(0x0)/Pci(0x3,0x0)/Pci(0x0,0x0)
  • PciRoot(0x0)/Pci(0x1,0x0)/Pci(0x0,0x0)
    • Reason: Required to ensure Brightness Control works on upgraded iMacs
    • Logic: Sets AppleBackLight properties
    • Models: iMac11,x and iMac12,x with upgraded Nvidia Metal GPUs
  • PciRoot(0x0)/Pci(0x2,0x0)
    • Reason: Disables internal GPU to fix sleep issues on upgrades iMacs
    • Logic: Tricks macOS into thinking iGPU is a generic PCI device
    • Models: iMac12,x with upgraded Metal GPUs

# Kernel -> Patch

  • SMC Patch
    • Reason: Required to avoid SMC Firmware updates
    • Logic: Patches out smc-version in AppleSMC.kext, requires SMC-Spoof.kext for full functionality
    • Models: All models require when spoofing SMBIOS
  • IOHIDFamily Patch
    • Reason: Required for HID peripheral support in macOS on older hardware
    • Logic: Tricks IOHIDFamily into thinking it's always booting recovery
    • Models: Penryn CPUs (Core2 series)

# Kernel -> Quirks

  • ThridPartyDrives
    • Reason: Required to avoid Hibernation wake issues on 3rd party drives
    • Logic: Patches AppleAHCIPort.kext into support
    • Models: All models with standard SATA ports
  • PanicNoKextDump
    • Reason: Avoids kext dump on kernel panics, easier kernel debugging
    • Logic: Patches Kernel to not dump dump unnecessary info
    • Models: Only set when Verbose Boot is enabled by the user

# Misc -> Security

  • SecureBootModel
    • Reason: Required to ensure seamless OS updates with Big Sur
    • Logic: Sets iMacPro1,1's Secure Enclave Identifier (j137)
    • Models: All models require

# NVRAM -> Add

  • -v debug=0x100
    • Reason: Used to see debug info of macOS's kernel and kexts, and avoids reboots on panic
    • Logic: Adds args to NVRAM
    • Models: Only set when Verbose Boot is enabled by the user
  • -liludbgall
    • Reason: Enables Lilu and plugin debug logging
    • Logic: Adds args to NVRAM
    • Models: Only set when Kext DEBUG is enabled by the user
  • msgbuf=1048576
    • Reason: Sets message buffer size to 1MB, ensures boot logs are retained
    • Logic: Adds args to NVRAM
    • Models: Only set when Kext DEBUG is enabled by the user
  • agdpmod=pikera
    • Reason: Fixes GPU switching on MacBookPro9,x
    • Logic: Adds args to NVRAM
    • Models: MacBookPro9,x
  • shikigva=80 unfairgva=1
  • shikigva=128 unfairgva=1 -wegtree
    • Reason: Fixes DRM support on models with upgraded AMD Metal GPUs
    • Logic: Adds args to NVRAM
    • Models: Models with upgraded AMD Metal GPUs

# UEFI -> ProtocolOverrides

  • GopPassThrough
    • Reason: Used for proper output on machines with UGA firmware but GOP GPU
    • Logic: Provide GOP protocol instances on top of UGA protocol instances
    • Models: MacPro3,1, MacBook4,1 iMac7,1-8,1

# Injected Kext

Below is an explanation of what Kexts OpenCore Legacy Patcher will inject into memory on boot-up.

Injected Kext Explanation

# Acidanthera

  • Lilu
    • Reason: Patching engine for other kexts
    • Models: All models require
  • WhateverGreen
    • Reason: Patches GPU Frameworks and kext to ensure proper support
    • Models: All models require
  • CPUFriend
    • Reason: Patches IOx86PlatformPlugin to restore previous CPU profiles
    • Models: 2012 and newer models
  • AirportBrcmFixup
    • Reason: Patches IO80211 and co to fix networking support for unsupported cards
    • Models: BCM943224 and BCM94331
  • RestrictEvents
    • Reason: Disables memory errors on MacPro7,1
    • Models: Mac Pros and Xserves

# Ethernet

  • nForceEthernet
    • Reason: Inject old Nvidia Ethernet kext to resolve networking in Catalina and newer
    • Models: 2010 and older Nvidia Ethernet require
  • MarvelYukonEthernet
    • Reason: Inject old Marvel Ethernet kext to resolve networking in Catalina and newer
    • Models: 2008 and older Marvel Ethernet require
  • CatalinaBCM5701Ethernet
    • Reason: Inject old Broadcom Ethernet kext to resolve networking in Big Sur
    • Logic: Patch out conflicting symbols to not colide existing BCM5701Ethernet
    • Models: 2011 and older Broadcom Ethernet require

# Maps

  • USBMap
    • Reason: Inject old USB map profiles to fix USB
    • Models: All models require


  • AAMouSSE
    • Reason: Translates SSE4.2 instructions to compatible code for SSE4,1 CPUs, required for AMD Metal drives
    • Models: MacPro3,1
  • telemetrap
    • Reason: Ensures temelemtry.plugin doesn't run, required for SSE4,1 CPUs
    • Models: Penryn CPUs

# Wifi

  • IO80211HighSierra
    • Reason: Re-inject Atheros wifi drivers from High Sierra
    • Logic: Patch out conflicting symbols to not colide existing IO80211Family
    • Models: Atheros cards
  • IO80211Mojave
    • Reason: Re-inject Broadcom wifi drivers from Mojave
    • Logic: Patch out conflicting symbols to not colide existing IO80211Family
    • Models: BCM94322

# Misc

  • AppleBackLightFixup
    • Reason: Patch AppleBacklight for iMacs with Nvidia Metal GPU upgrades
    • Models: iMac11,x, iMac12,x with upgraded Nvidia Metal GPUs
  • AppleIntelPIIXATA
    • Reason: Fix IDE support on MacPro3,1
    • Models: MacPro3,1
  • AppleIntelMCEDisabler
    • Reason: Fix dual socket support in Catalina and newer
    • Models: Mac Pros and Xserves
  • NightShiftEnabler
    • Reason: Enables NightShift support on unsupported models
    • Models: 2011 and older, MacBookPro9,x included
  • SMC-Spoof
    • Reason: Spoofs SMC version to 9.9999
    • Models: All models require

# On-Disk Patches

Unfortunately certain on-disk patches are required to achieve full functionality. Below is a breakdown of patches supported

Audio Patches

# Extensions

  • AppleHDA
    • Reason: Re-add El Capitan's AppleHDA to achieve audio support
    • Models: iMac7,1 and iMac8,1
Acceleration Patches

# Extensions

# General Patches

  • IOSurface.kext
    • Reason: Fixes immediate logout on login
    • Logic: Downgrade to Catalina IOSurface
    • Note: For AMD and Intel, additional addMemoryRegion/removeMemoryRegion patch added changing the first conditional jump to non conditional jump
      • At Offset 0xdb52 and 0xdbc6, replace following bytes with 0xeb

# Dropped Acceleration Binaries

  • Nvidia Binaries

    • GeForceGA.bundle
    • GeForceTesla.kext
      • Skip IOFree Panic - Mojave+
        • At Offset 0x5CF9A replace following bytes with 0xEB
      • Avoids addMemoryRegion/removeMemoryRegion calls
        • At Offset 0x5527 and 0x77993, replace following bytes with 0x909090909090
    • GeForceTeslaGLDriver.bundle
    • GeForceTeslaVADriver.bundle
    • NVDANV50HalTesla.kext
    • NVDAResmanTesla.kext
      • 0x1ea59a - 0x1ea5b3: nop
      • Replace VSLGestalt to IOLockLock or any other known symbol of the same length.
  • AMD/ATI Binaries

    • AMD2400Controller.kext
    • AMD2600Controller.kext
    • AMD3800Controller.kext
    • AMD4600Controller.kext
    • AMD4800Controller.kext
    • AMD5000Controller.kext
    • AMD6000Controller.kext
    • AMDFramebuffer.kext
    • AMDLegacyFramebuffer.kext
    • AMDLegacySupport.kext
    • AMDRadeonVADriver.bundle
    • AMDRadeonVADriver2.bundle
    • AMDRadeonX3000.kext
    • AMDRadeonX3000GLDriver.bundle
    • AMDShared.bundle
    • AMDSupport.kext
    • ATIRadeonX2000.kext
    • ATIRadeonX2000GA.plugin
    • ATIRadeonX2000GLDriver.bundle
    • ATIRadeonX2000VADriver.bundle
  • Intel 5th Gen Binaries

    • AppleIntelFramebufferAzul.kext
    • AppleIntelFramebufferCapri.kext
    • AppleIntelHDGraphics.kext
    • AppleIntelHDGraphicsFB.kext
    • AppleIntelHDGraphicsGA.plugin
    • AppleIntelHDGraphicsGLDriver.bundle
    • AppleIntelHDGraphicsVADriver.bundle
  • Intel 6th Gen Binaries

    • AppleIntelHD3000Graphics.kext
    • AppleIntelHD3000GraphicsGA.plugin
    • AppleIntelHD3000GraphicsGLDriver.bundle
    • AppleIntelHD3000GraphicsVADriver.bundle
    • AppleIntelSNBGraphicsFB.kext
      • Board ID Patch
        • Replace original Board ID with updated model
    • AppleIntelSNBVA.bundle

# Frameworks

  • CoreDisplay.framework
    • Logic: Copied from Mojave, heavy modifications/shims
  • IOSurface.framework
  • OpenGL.framework
    • Logic: Copied from Mojave

# PrivateFrameworks

  • GPUSupport.framework
    • Logic: Copied from Mojave
  • SkyLight.framework
    • Logic: Copied from Mojave, heavy modifications/shims

# LaunchDaemons

  • HiddHack.plist
    • Reason: Fixes unresponsive input when patching Skylight
    • Logic: Forces hidd to register events, as Skylight handles them by default in Big Sur