Gigabyte Z270X-UG

Currently two issues are present:

  1. CPU idles down to ~1.8GHz. Will not drop to 800MHz.
    • While SSDT plugin works to a degree, I have tried to debug this issue and am unable to. PRgen does not work at all. Literally generates one state. Dropping CPU SSDT can cause boot failures and introduces a different issue.
  2. PowerNap, Sleep and Hibernate do not function. System goes for this power state and hangs. Powered on but in a frozen state. Does not respond to input. Screen is black.
    • Since CPU can’t idle correctly, these are never expected to work.
    • USB controller affects this feature. Boards with ASMedia, like mine, are not natively supported in macOS. They do function when mapped, but not being able to be natively control with power states prevents macOS from changing states.

This EFI was created using firmware version F9d. If you use an older verison, consider upgrading. While in theory it should be fine to use an older version, you never know.

  • 6th gen Skylake CPUs will use iMac 17,x.
  • 7th gen Kabylake CPUs will use iMac 18,x.

I consider this complete at this point. All else has been worked out. I will keep it updated as needed. With each OC version I will attempt to debug CPU power states.

Z270 Series

Device UD3 UD5 G5 G7 G8 G9 GK3 GK5 GK7 UG
HDMI Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
DisplayPort No Yes Yes Yes Yes Yes No Yes Yes No
ThunderBolt No Yes No Yes Yes Yes No No No No
USB Controller ASMedia Intel ASMedia Intel Intel Intel ASMedia ASMedia ASMedia ASMedia
Audio ALC1220 ALC1220 ALC1220 Creative 3D Creative 3D Creative 3D ALC1220 ACL1220 ALC1220 ACL1220
LAN Intel Intel Intel & Killer Intel & Killer Intel & Killer Killer Killer Killer Intel & Killer Intel
WiFi No No No No Killer Killer No No No No

Using this EFI as a reference will work for most of the boards in this lineup. You cannot use it as reference for Gaming 7, 8 and 9. Gigabyte tends to design their boards the same way so the firmwares are really similar. However, some of these are not the best choice and will leave you with devices that do not work. Boards with Creative Audio and Killer WiFi should be avoided. Killer LAN is supported.

CFG Lock

You should follow the guide and disable this lock. This is a much cleaner solution than leaving the quirks enabled. I have left them enabled by default so you can boot without a stall. The instructions tell you to use setup_var. However, setup_var2 and setup_var3 are alternatives if you get an error.

USB Patching

You can do this one of two ways: Kext or SSDT for OpenCore. Clover is just SSDT. I included the SSDT, kext and an image inside post_install for reference. If you have the exact same number of ports or use the same ports I do, you can use the USB kext. I use one internal USB header (internal at the bottom) for the X62, and one USB 3.0 header (lower right of RAM) to connect two 3.0 ports on the case. The rest of the rear ports fit within the limit and are enabled. If you want to adjust your ports, enable the port limit patch and follow the guides. For Kext and SSDT you can use a tool called USBMap. The guide favors kext method. To manually create an SSDT read here.

  • USBMap-17.kext is for iMac17,x
  • USBMap-18.kext is for iMac18,x

If you intend to use the prebuilt kext, you should select the one for your model and rename it to USBMap.kext and place it in /EFI/OC/Kexts. The USB Port limit patch is enabled. Please disable it if you do not intend to create your own layout.


Like Clover, OpenCore works best with this board using emulated NVRAM. I gave it a shot with OC, and while it does work, it is unstable. I recommend you do not use native NVRAM. If you use native NVRAM you may experience the following:

  • Logout hangs.
  • Rebooting results in no input response for F12 or DEL.
  • Phantom boot entries.
  • Random behavior from firmware.

I have already enabled the emulation in the config. You will need to follow the instructions to complete the setup post-install so values can be written on logout.

Big Sur (11.0)

iMac 17,x and iMac 18,x are supported models.

v0.6.3 is required to boot. At the moment I am not updating because there is a compatibility problem with WhateverGreen in regards to DRM. Big Sur has many changes. Any isues you have booting will have to be debugged on your own.

Debug Branch

This branch has all logging turned on. It is slower to boot. This branch is where I will be keeping all testing done so as to not interfere with the master branch in case I screw up.

See WIKI for additional information.