CustoMac, Golden Build

[Guide]Catalina Update! 10.15 in X299 Designare EX or Z300 Series with RX 5700XT (Radeon Pro W5700) + Dual Ultrafine 5K

This guide shows successfully running my iMac Pro intel 8th, 9th CPU’s Customac Build with macOS Catalina. You can also System Update up to the newest one smoothly after finishing the installation.

This post constitutes a new macOS 10.15 Catalina Desktop Guide for intel’s 8th and 9th CPU, which certainly can still grow and improve by your estimated user feedback. This macOS 10.15 Catalina Desktop Guide based on the Gigabyte X299 Designare EX. However, also other X299 series mainboard models or 300series mainboards of other brands might be compatible with this guide after likely considering and implementing few mandatory modifications not accounted by this guide. If you want to see previous Guide for macOS Mojave I linked it below for your convenience. The Mojave guide including some other MB’s EFIs conveys a common guide not only 300series but also X299series. But this Catalina guide is only for X299 Designare EX but limited for the X299 Series as well.

Before starting with all detailed instructions, please find a Hardware Overview that provides a buying idea for your own RIG addressed within this guide

A) Hardware Overview

  • CPU: Intel Core i9-9900X Skylake 10-Core 3.5 GHz (4.5 GHz Turbo) LGA2066.
  • Motherboard: Gigabyte X299 Designare EX (Ver.1.0)
  • GPU: Sapphire Radeon RX 5700XT 8GB
  • Ram Memory: 128GB G.SKILL DDR4 16gb x 8ea, 3000mhz
  • System Disks: 2 x WD SN750 1TB NVME for macOS Catalina and Backup + 1 x Samsung 960 EVO NVME 500gb (Win10)
  • Power: EVGA Supernova 1300W G2
  • Case: Deep Cool Quadstellar
  • Mouse & Keyboard: Razer Mamba HYPERFLUX & FIREFLY HYPERFLUX BUNDLE, Apple Magic Keyboard Grey and Tracpad 2 Grey
  • Monitors: 2 x LG UltraFine 5K
  • CPU Cooling System: NZXT Kraken X62 (RL-KRX62-02) Liquid Cooling

B) Gigabyte BIOS Configuration You can change the BIOS setting to Optimized Default and change it to the following settings. If possible, update the BIOS to the latest version. Depending on your Gigabyte boards and the BIOS version, there may be a difference in the names, but there seems to be no major difference. Once you have set up your MacOS installation, it’s a good idea to change it to your own configuration later.  

1.) /M.I.T/Advanced Frequency Settings/
a.) Extreme Memory Profile: (X.M.P): Profile1

2.) /M.I.T/Advanced Frequency Settings/Advanced CPU Core Settings

a.) Active Cores Control: Auto
b.) Hyper-Threading Technology: Enabled
c.) Intel Turbo Boost Max Technology 3.0: Enabled
d.) Intel Speed Shift Technology: Enabled
e.) Enhanced Multi-Core Performance: Enabled/Disabled

3.) /M.I.T/Advanced Memory Settings/
a.) Extreme Memory Profile (X.M.P): Profile1

4.) /BIOS/
a.) Boot Numlock State: Disabled/Enabled
b.) Security option: Setup
c.) Full-Screen Logo Show: Enabled
d.) Fast Boot: Disabled
e.) CSM Support: Disabled

5.) /BIOS/Secure Boot/
a.) Secure Boot Enable: Disabled

6.) /Peripheral/Thunderbolt Configuration/
a.) Security Level: No Security b.) Thunderbolt Device Boot option: Enabled

7.) /Peripherals/USB Configuration/
a.) XHCI Hand-off: Enabled

8.) /Chipset/
a.) VT-d: Disabled (If you use other virtual programs in macOS you could do enable with ‘dart=0’ option in config.plist)

9.) /Power/
a.) Platform power management: Disabled

10.) F10 /Save& Exit/

C) iMac Pro macOS 10.15 Catalina System Setup

Below, one finds a detailed description of the Clean Install of macOS Catalina 10.15 – Special iMacPro build. This also includes the iMacPro EFI-Folder Preparation as well as the iMac Pro macOS Catalina 10.15 Installer Package and iMac Pro macOS Catalina 10.15 USB Flash Drive Installer Creation.

C.1) iMac Pro EFI-Folder Preparation

In order to successfully boot a macOS USB Flash Drive Installer or System Disk on a Customac system, both drives must be equipped with an EFI-Folder in their EFI partitions. In this section, we will prepare a fully equipped EFI-Folder with SMBIOS iMacPro1,1 System definition.

1.) Download and unzip my macOS Catalina to your Desktop.

X299 Gigabyte Z370 Aorus Gigabyte Z390 Gigabyte Z390 Aorus

2.) Open the config.plist in /EFI/Clover/ with the latest version of Clover Configurator, proceed to the “SMBIOS” Section and complete the SMBIOS iMacPro1,1 Serial Number, Board Serial Number, and SMUUID entries.

These details are mandatory to successfully run iMessage and FaceTime on your iMac Pro System. Note that all other iMacPro1,1 SMBIOS Details are already implemented in the config.plist

Press several times the “Generate New” Button next to serial number text field.

In the final step, open a terminal, enter repeatedly the command “uuidgen”, and copy the output value to the SMUUID field in the “SMBIOS” Section of the Clover Configurator. Or you can simply “Generate New” Button next to SMUUID text field.

Finally, save the modified config.plist.

You now have a fully equipped EFI-Folder.

C.2) iMac Pro macOS Catalina – Installer package and a bootable USB Creation

To make the macOS Catalina  – Installer follow the individual steps below:

*You should have Catalina downloaded from the Mac App Store

Verify your “Install” for completeness. You should now have a complete macOS Catalina Installer package in your /Applications Folder.

Follow the individual steps detailed below to successfully create a bootable iMac Pro macOS Catalina 10.15 USB Flash Drive Installer.

1.) Format a USB Flash Drive of your choice (source, named USB) [(Mac OS Extended (Journaled)] and a GUID partition table by means of Apple’s Disk Utility on any other Hackintosh or Mac of your choice. This will create an empty Partition and a yet empty EFI-partition on your iMac Pro macOS USB Flash Drive Installer.

2.) With the macOS Catalina 10.15 Installer Package in your /Application Folder, connect your USB Flash Drive (named USB) and run the following terminal command:

sudo /Applications/Install\ macOS\ --volume /Volumes/USB /Applications/Install\ macOS\ --nointeraction

3.) For successfully booting your iMac Pro macOS USB Flash Drive Installer, it must contain a valid EFI- Folder with an SMBIOS iMacPro1,1 system definition. Thus, copy the EFI-Folder you prepared in Section C.1) to the yet empty EFI Partition of your macOS USB Flash Drive Installer. Mount your USB’s EFI using Clover Configurator and Copy your EFI folder to the mounted USB’s EFI.

You now have a fully functional and bootable macOS Catalina 10.15 USB Flash Drive Installer.

C.3) iMac PromacOS Catalin 10.15 Clean Install

Follow the individual steps detailed below to successfully setup macOS Catalina 10.15 on a virgin system drive of your choice (NVMe, SSD or HDD).

1.) In order to perform a clean install of macOS Catalina 10.15, prepare a virgin NVMe, SDD or HDD destination drive for the iMac Pro macOS installation by formatting the drive [(Mac OS Extended (Journaled)] and a GUID partition table by means of Apple’s Disk Utility on any other Customac or Mac of your choice. This will create an empty Partition and a yet empty EFI-partition on the drive.

2.) Copy the EFI-Folder you prepared in Section C.1) to the yet empty EFI Partition just like you did it for your USB installer bootable.

3.) Now connect the Destination Drive to your Customac System and boot the latter with the plugged macOS Catalina 10.15 USB Flash Drive Installer, created in Section C.2)

4.) While booting your system, press the “F12” and Select to boot from your macOS USB Flash Drive Installer.

5.) Subsequently, click on the USB Flash Drive Installer Icon in the clover boot menu to boot the respective macOS Installer partition on your macOS USB Flash Drive Installer.

6.) After a successful boot, pass the individual steps of the macOS Catalina 10.15 installation menu and finally select the destination drive of your macOS Catalina 10.15 Installation, which should be logically the system disk you successfully configured above. In the next step, the Installer will create a macOS Catalina 10.15 Installer Partition on the system disk and subsequently reboot your system.

7.) During the system reboot, just press again the F8 button to enter the BIOS boot menu. Select again to boot from your USB Flash Drive. In contrary to 6.), click this time on the “Install MacOS..” icon in the clover boot screen to boot the newly created macOS Catalina 10.15 Installer Partition on your system disk.

8.) After the successful boot, you will enter now the macOS Catalina 10.15 Installer Screen with a progress bar starting at about 34 minutes.

9.) After another reboot, press “Del” button to enter the BIOS boot menu. Select to boot with your System Disk EFI-folder as primary and save/exit. Click on the “macOS Catalina” icon on the clover boot screen to boot the new macOS Catalina partition of your system disk.

10.) After successful boot ignore the requested iCloud registration (You can do this after logged in) and you will have your first iMac Pro macOS Catalina 10.15 system.

D) Post Installation Process

There are not many things you should do if you are using my However, there are couple things to do look nice and stable in your Customac.

D.1) System Overview CPU Cosmetics

Use below link to fix your CPU Cosmetics.

D.2) Gigabyte X299 Designare EX PCI Device Implementation (Optional guide for buyers only)

This is a totally optional guide to imply your PCI Devices’ information in your System profile using proper SSDTs.

SSDTs for Thunderbolt Hotplug fix and USB port limit patch are very convenient from the latter OS updates. Unfortunately, Thunderbolt3 HotPlug function is broken in X299 Designare EX. I am still working on to fix this. For now, only one port is working for HotPlug but limited in certain devices only. However, I included it in the folder for the users who are interest to have cosmetic purpose. Z390 Designare and other MB with TB3 Cards (Alpine Ridge and Titan Ridge) are working fine with SSDT.

The more detail information is on the download page.

If you are using different slot number or change model name etc, use MaciASL tool.

Open SSDT file that you want to modify and replace the value and save it.

Dual displays – LG ultrafineDisplay 5K Display (TB3)


Now you have the most advanced macOS in intel’s Desktop system.

If you have any questions, leave comments or e-mail to

Last modified: May 6, 2020

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Edward Smith
Edward Smith

I use RX580 graphic cards in my system. What needs to be modified for the EFI to work…

Thatcher Kelley
Thatcher Kelley

I’m following the steps with the same hardware configuration. Clover boots, but no “Install Mac OS” icon shows up. The only hitch is I only have Catalina 10.15.3 instead of .1
Is that a problem?

Ace Guerra
Ace Guerra

Hey, great guide. I was able to install and boot to Catalina but some stuff is it working. I can pay you, and was wondering if you could help me. I have the same board just some other different hardware. Let me know please. Thanks


Can you verify payment, as it went through but i never got to download.


Can you please update your guide? I purchased this for the designare ex and did all the necessary kexts, flags, and updates still no go. Can’t even boot the installer. Just did the z390 master (with another guide and took less than 10mins, fully functional/stable. If not please refund me. Thanks in advance