iATKOS | United Kingdom

If you want to downgrade your MacBook Air 2017 from macOS Sequoia to Sonoma without using OCLP, and then update your iMac 2017 from Ventura to Sonoma with a fresh start using OCLP, follow this structured guide to ensure a smooth and safe transition.

Step 1: Downgrade MacBook Air 2017 to macOS Sonoma Without OCLP

Since the MacBook Air 2017 natively supports macOS Sonoma, you can completely remove OCLP and reinstall Sonoma.

1. Backup Your Data

• Use Time Machine or another backup tool to save all important data.
• Confirm your backup is complete before proceeding.

2. Create a macOS Sonoma Installer USB

1. On a working Mac, download macOS Sonoma from the App Store.
2. Use the createinstallmedia command in Terminal to create a bootable USB:

   bash
   Copy code
   sudo /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/createinstallmedia --volume /Volumes/YourUSBDrive
   

3. Insert your formatted USB drive, replacing "YourUSBDrive" with the USB name.

3. Erase and Reformat the Drive

1. Insert the USB installer into the MacBook Air.
2. Restart and hold Option (⌥) during boot to select the USB as the boot device.
3. Once in the macOS installer:
   • Open Disk Utility.
   • Select your internal drive.
   • Click Erase, and format it as APFS with a GUID Partition Map.

4. Reinstall macOS Sonoma

1. Follow the on-screen instructions to install macOS Sonoma.
2. Restore data from your backup if needed.

Step 2: Remove OCLP Residual Files from the MacBook Air

Since Sonoma is natively supported, you no longer need OCLP. Completely remove any traces of it.

1. Remove OCLP EFI Partition (if applicable)

1. Boot your MacBook Air into macOS Recovery.
2. Open Terminal and mount the EFI partition (optional).
3. Check if there is a custom OCLP EFI folder and remove it.

2. Reset NVRAM/PRAM

1. Restart the Mac and immediately hold Option + Command + P + R.
2. Continue holding until the startup sound plays twice. This clears any OCLP boot arguments.

Step 3: Update iMac 2017 to macOS Sonoma Using OCLP

The iMac 2017 does not natively support macOS Sonoma but can be upgraded using OpenCore Legacy Patcher.

1. Backup Your Data

• Use Time Machine or another backup tool to safeguard your data before upgrading.

2. Prepare a macOS Sonoma Installer with OCLP

1. Download the latest version of OCLP from its GitHub page.
2. Download macOS Sonoma from the App Store.
3. Create a bootable USB installer using the createinstallmedia command in Terminal (same steps as Step 1).

3. Install macOS Sonoma

1. Insert the USB installer into the iMac.
2. Restart and hold Option (⌥) to boot from the USB drive.
3. In the installer:
   • Open Disk Utility.
   • Ensure your drive is formatted as APFS.
   • Proceed with the installation.

4. Apply Post-Install Patches Using OCLP

1. After installation, boot into macOS Sonoma.
2. Open the OCLP app and run Post-Install Patches:
   • This ensures proper functioning of hardware components like Wi-Fi, Bluetooth, and graphics.
3. Restart the iMac after applying patches.

Best Practices and Additional Notes

• Troubleshooting:

  • If patches don’t apply correctly, check the OCLP GitHub Issues page or community forums.
  • Boot in Verbose Mode (-v) if macOS fails to load to diagnose issues.

• Stability:

  • macOS Sonoma is still being refined for unsupported Macs. Expect minor bugs.
  • Keep OCLP updated to access new fixes and improvements.

• Backups:

  • Always maintain a full backup before making OS-level changes, especially with unsupported hardware.

Conclusion

By following these steps:

• Your MacBook Air 2017 will run a clean, unpatched version of macOS Sonoma.
• Your iMac 2017 will be upgraded to macOS Sonoma with OCLP for full functionality.

Let me know if you encounter specific challenges or need clarification! Good luck!