Can I Downgrade from Big Sur to High Sierra?

[wstrohm]

Okay, I realize it's a weird question, but I have my reasons. Can I use my OpenCore 0.6.4 in the EFI folder of the formerly working Big Sur computer, once it's downgraded to High Sierra? And will the bootloader still work running the HFS+ filesystem, after it has been working with APFS?

My process would be:
1) Save the OpenCore 0.6.4 EFI folder to an external storage device.
2) Erase the Big Sur disk and delete the contents of its EFI folder.
3) Install High Sierra using a High Sierra Installer on a previously Unibeast-created USB flash drive, after typing RehabMan's magic "don't install APFS" command into Terminal.
4) Delete the installer's EFI folder and copy the saved OpenCore EFI folder into the EFI partition of the High Sierra boot disk.
5) Hopefully I would have a High Sierra installation on a HFS+ formatted disk using an OpenCore 0.6.4 EFI bootloader.

Any opinions?

 

[wstrohm]

Okay, I now have High Sierra 10.13.6 (Build 17G66) working on my "Mini-ITX 4" computer (at left). And I have installed Clover v 5127. But the weirdness never stops. It seems I have two EFI volumes... one opens using Clover Configurator and the other opens using OpenCore Configurator. How do I delete the OpenCore EFI volume? I want to run High Sierra using Clover. Is this easily done in Terminal? If so, how?

 

[wstrohm]

Done. 10.13.6 build 17G14042 running using Clover R5119 on my "Mini-ITX 4" (left and below). I like it.

 

[Feartech]

Done. 10.13.6 build 17G14042 running using Clover R5119 on my "Mini-ITX 4" (left and below). I like it.

moved to Desktop Support