Not long ago, it was said that it was impossible to boot a Z490 based 11-gen system on High Sierra, and it was also said that it could not run Opencore. Well folks, this is the guide you've all been waiting for! This system is both High Sierra AND
View attachment 508825
View attachment 508813
View attachment 508814
View attachment 508815
View attachment 508816
View attachment 508817
View attachment 508818
View attachment 508822
View attachment 508909
View attachment 508823
View attachment 509084
View attachment 508819
View attachment 508820
View attachment 508821
View attachment 510479
Background to the system
My main Z68 Asus system at home for gaming and work was getting a bit long in the tooth, and I wanted an upgrade to the latest available equipment (to handle Cyberpunk 2077 and the like), as well as have it set up with all the bells and whistles of RGB lighting. Instead of settling for a mid-range board this time I decided to settle on a top-end Z490 board from Gigabyte - specifically the Z490 Aorus Xtreme, which is an extremely high-specced motherboard that comes with Thunderbolt 3 as well as PCIe 4.0 support. As the PCIe 4.0 compatible CPUs weren't yet available from Intel at the time of writing, I'd decided to settle on a low-end Core i5 10400 to run the system until the 11th gen CPUs were available.
Initially I'd wanted to use a smaller case such as Thermaltake 20MT - but found out as the Xtreme uses an E-ATX sized board, I had to find a larger case as it is too small. I'd then found a Thermaltake 20GT ARGB - but saw this option was not available where I was based, so I had to settle for the next best model which was the 20GT RGB Plus.
I did not expect it, but the 20GT RGB Plus is a huge
case, and with tempered glass all round, it is also one of the heaviest I've yet owned (at 20kg). It comes with its own RGB controller as well as a small set of RGB fans. It is also well built. This time I'd decided on spending a bit more on the furnishings of the system, so I decided on a 70% Thermaltake 30% Gigabyte mix, buying most of my parts from both brands. I sourced the fans, motherboard and all other parts from local dealers including the Gigabyte 1TB copper-plated PCIe 4.0 NVMe SSD and Thermaltake RGB 32GB Toughram (which can be controlled by software).
For the graphics card, I originally wanted the Nvidia GTX 3080 for this setup. But as I couldn't get hold of one, decided to settle on a GTX 1060 6GB card which I carried over from the previous system. I'd wanted to be able to run both Windows and macOS so had two NVMes installed into the board's 2/3 NVMe slots.
View attachment 508910
I specifically wanted to run High Sierra on the system - mainly because I had my Nvidia card and didn't want to lose any compatibility with it. Luckily my GTX 1060 is a Pascal card so it has the full compatibility.
The installation took roughly about 2 weeks to build on and off. I first routed and cleanly installed all the necessary power and signalling cables for the PSU, fans and motherboard, then began to install the fans and finally SSD drives and graphics card. For the fans I connected most of them to a central TT USB controller, which was then connected to the mainboard for full syncing.
View attachment 508911
I then installed Windows from a USB onto the Gigabyte NVMe, then later set up macOS on the Samsung NVMe.
For the RGB software in Windows I used TT's own RGB Sync software for the RAM as well as Gigabyte's AORUS controller software, and NZXT's CPU monitoring software.
(A note for Samsung users - if you want to install macOS onto the 970 Evo NVMe, it would be wise to update the firmware with Samsung Magician first before installing macOS onto it).
View attachment 508826
Other tools needed
- 2 x 16GB USB Keys (for Unibeast & Windows 10)
- Spare Hackintosh/Mac (for editing if necessary)
- USB 3.0 external slot drive (for copying/editing files and data)
- Superduper or Carbon Copy Cloner (for cloning drives)
- Windows 10 installation on spare SSD/HD or NVMe drive (optional)
- A copy of MountEFI https://github.com/corpnewt/MountEFI
- A copy of Opencore Configurator
- A copy of Clover Configurator
NVMe detection and bootup
Nvidia Web Graphics Driver & Intel GPU
USB 3.1, 3.0 & 2.0 (hot-plugging and eject on USB 3.1 works)
Full sound with volume adjustment and digital out
Full screen 1040P
2.5GBe & 10GBe Ethernet (both ports)
Making USB bootable installer:
Getting a copy of macOS High Sierra:
If you have a Windows only system you can follow this guide to make a bootable USB stick
but download High Sierra:
If you have a Mac, you can grab a copy of macOS using this script and running it in Terminal:
Most of the following instructions were run on a Mac:
To run script, right-click gibMacOS.command and select Open.
When you run the script it will show you a list of available downloads. You must select the 'full install' of High Sierra 10.13.6
Once it has downloaded you need to create the Mojave installer on the USB. To do this type this in Terminal:
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
Once it's done, you'll need to copy the following attached EFI folder onto your USB stick's bootable EFI partition. The file is a ZIP so must be decompressed first.
First you must run MountEFI to mount the USB's EFI partition. Right-click to open MountEFI.command script and then select your USB's number in the Terminal list. Type in your password, and your EFI root directory will appear in your Finder. Select the EFI partition and drag the EFI folder you downloaded into root.
You'll need to then run Opencore Configurator (right-click to Open) to add in your unique system UUID and board serials. So select the config.plist under /EFI/OC/config.plist and edit it.
Go to PlatformInfo on the left, and select Datahub - Generic - PlatformNVRAM tab on the top. Select generate underneath the UUID field on the right. It should create a unique system UUID key. You'll need to also do this for your system Serial Number and MLB field keys on the left. If your Serial Number or Board ID doesn't generate, you'll need to get a copy from Clover Configurator. Simply run Clover Configurator, go to the SMBIOS section, select the Mac model using the arrows key on the bottom right corner highlighting iMac18,3 and then simply copy the Serial Number on the left to Serial Number in Opencore, Board Serial Number on the right to MLB in Opencore Configurator, and the ROM value to the two ROM value fields in Opencore Configurator. What you should end up with is something looking like this. Then Save the file.
View attachment 508827
Make sure the top half of Databub section on top does NOT contain a UUID key or any other keys.
Preparing the BIOS:
To make macOS bootable you'll need to make it Hackintosh-friendly.
Boot into BIOS and change to the following settings:
Above 4GB Decoding Enabled
Secure Boot disabled
UEFI Boot Mode
I have included and added the relevant OC build and patches and updates to the attached EFI folder.
The EFI contains the following SSDTs, drivers and kexts derived from VectorSeven's OCHack EFI and CaseySJ's Z490 build:
Thanks to VectorSeven for the hard work of configurating files for the Z490 and High Sierra.
Why does this EFI setup work for High Sierra & Mojave?
I had a look through some of VectorSeven's config.plist settings compared to a typical OC list, and comparing the settings I think it works because part of it uses CPU spoofing along with a compatible SMBIOS for High Sierra/Mojave.
This is equivalent to setting the FakeCPUID in Clover. In the Kernel, he had originally used the value EB060800 for a Kaby Lake system, but I changed it to EA060900 (for Coffee Lake), and used a SMBIOS of iMac18,3 instead. There were many other settings, with some lines even missing from the config.plist. I have since restored them according to the Dortania guide. The only four settings that have not been changed are EnableWriteUnProtector=Yes, AppleDebug=No, PickerMode=External, and Keyswap=Yes. But I think the key change was definitely the CPUID spoofing, which allowed the system to boot.