Resolving USB & SATA Drive Detection Issues on GA-Z270X-Gaming 5 Hackintosh with Big Sur Transition

When transitioning from Clover to OpenCore and upgrading from macOS Mojave to Big Sur, there are substantial changes under the hood that can affect how your Hackintosh interacts with storage devices. If USB and SATA drives formatted with HFS/APFS are not mounting, here are several troubleshooting steps to consider:

1. Update Kexts and OpenCore

Make sure all your kexts are up to date with versions compatible with Big Sur. This includes kexts for USB controllers and SATA/AHCI controllers. Also, ensure you're running the latest version of OpenCore.

2. Check OpenCore Configuration

• USB Mapping: Big Sur has more stringent requirements for USB port mapping. If you're using a pre-existing EFI from another build, the USB mapping may not be correct for your system. Use a USB mapping kext or tool to map your ports correctly.
• SATA Configuration: Verify that the SATA controller kexts and patches in your config.plist are set up for your specific motherboard. You might need to adjust these settings to ensure Big Sur recognizes your drives correctly.

3. Verify BIOS Settings

• AHCI Mode: Double-check that the BIOS is set to AHCI mode, which you've mentioned is already done.
• Intel Rapid Storage Technology (RST): Even without a Windows partition, ensure that RST is disabled in the BIOS, as it can interfere with how macOS interacts with SATA drives.

4. Remove Unnecessary Kexts

• Raid Kext: If you had a sasmegaraid kext and you don't have a hardware RAID configuration, it's good that you've disabled it. To ensure it's not affecting the system, you could try removing it entirely from your EFI folder.

5. Disk Utility and Terminal Commands

• Disk Utility: Boot into macOS Recovery, and use Disk Utility to see if the drives show up there.
• Terminal: Use Terminal commands like diskutil list to see if the system recognizes the drives at all.

6. Reset NVRAM

Sometimes, the NVRAM holds onto old boot settings which can cause issues. Resetting it might help:

• Restart your computer and immediately press and hold Option + Command + P + R.

7. Review System Logs

• Console: Use the Console app within macOS to review system logs for any error messages related to mounting drives.

8. Check for Physical Connections

Ensure that all cables and connections to your drives are secure. A loose SATA or power cable can cause the drive not to mount.

9. Test with Known Good Configurations

If you have access to the previous EFI folder that worked with Clover and Mojave, you could try booting with that (if still possible) to see if the drives mount, which would suggest a configuration issue with the new EFI folder.

10. Community Support

Seek advice from the Hackintosh community specific to your motherboard, as they might have encountered and solved similar issues.

Remember, diagnosing Hackintosh issues can sometimes be a trial-and-error process, and it’s important to take changes step-by-step and test extensively after each change. Backup your current EFI folder before making any changes so you can revert if needed.