In general I followed the OpenCore installation Guide.

• Create a bootable USBStick
  • Installer Guide
• Follow the Comet Lake instructions (config.plist)
• and so on...

• Tweak
  • Advanced CPU Settings
    • VT-d: Enabled
    • Intel Speed: Enabled
• Settings
  • IO Ports
    • Above 4G Decoding: Enabled
    • Network Stack Configuration
      • Network Stack: Disabled
• Boot
  • CFGLock: Disabled
  • Window 10 Features: Windows 10
  • CSM: Should be disabled to get rid of legacy code from DSDT but unfortunately Radeon RX 580 does not work with CSM disabled. I have it enabled.

• Version: 0.7.7
• Compatible macOS: 10.14 to 12.1
• System Definition: iMac 20,1

EFI
├── BOOT
│   └── BOOTx64.efi
└── OC
    ├── ACPI
    │   ├── SSDT-AWAC.aml
    │   ├── SSDT-EC-USBX-DESKTOP.aml
    │   ├── SSDT-PLUG-DRTNIA.aml
    │   ├── SSDT-RHUB.aml
    ├── Drivers
    │   ├── HfsPlus.efi
    │   ├── OpenCanopy.efi
    │   └── OpenRuntime.efi
    ├── Kexts
    │   ├── AppleALC.kext
    │   ├── Airportltwm.kext
    │   ├── IntelMausi.kext
    │   ├── Lilu.kext
    │   ├── NVMeFix.kext
    │   ├── USBInjectAll.kext
    │   ├── VirtualSMC.kext
    │   └── WhateverGreen.kext
    ├── OpenCore.efi
    ├── Resources
    │   ├── Font
    │   ├── Image
    │   │   └── Acidanthera
    │   │       ├── Chardonnay
    │   │       ├── GoldenGate
    │   │       └── Syrah
    │   └── Label
    └── config.plist

If you already have macOS installed but want to perform a clean install, you can either download macOS from the App Store or use ANYmacOS. If you have not updated to BigSure for example you can download it from the AppStore. After the download you can find the downloaded macOS in the Applications folder.

If you are on Windows or Linux, follow the guide provided by Dortania

I will skip some steps because it could lead to an endless readme. I will point out some important configs that you should be aware of.

• Getting the Intel(R) I225-V Ethernet Controller to work:

  • NOTE: For getting the I225 Controller to work in macOS Monterey, version beta 7 is required at least! - nothing else has to be changes at Monterey.
  • macOS Big Sure need following changes:
    • Enable (un-comment with a #) DeviceProperties: #PciRoot(0x0)/Pci(0x1C,0x1)/Pci(0x0,0x0)
    • Go to Kernel: Patch and enable I225-V Patch.
    • Disable or Delete boot-arg dk.e1000=0.

• Create SMBIOS infos for iMac20,1 to the config.plist and save it.

• Copy the EFI Folder to a FAT32 formatted USB Stick

• Reboot from USB Stick

• Boot macOS

• Continue with installing macOS

Once you got macOS running copy the EFI Folder from the USB Stick to the EFI Folder to the System.

• Acidanthera and Team for the OpenCore Bootloader
• Dortania for OpenCore Install Guide
• TECHNolli [Technolli])(https://www.technolli.com/)