MP 1,1-5,1 How to Zap a corrupt OCLP Drive

[LookToWindward]

Hi,

Long Story short, I was using OCLP 1.3.0 and had installed Sonoma on a MacPro 3,1. All was working well until I restarted Saturday morning and found the Sonoma drive was corrupt. I have a Drive containing El Capitan which boots without OCLP. I then found out that OCLP 1.3.0 has a bug that causes the recovery not to work.

I decided to try again with OCLP 1.1.0 and Monterey so I installed it on a newly formatted HD, this seems to work ok, but when I put the old Sonoma drive in the machine it causes a Freeze No Caps Lock as soon as I attempt to access any OC volume (e.g. I can't boot from Monterey).

I can re-format the drive from El Capitan but is there anyway of removing the OCLP partitions from El Capitan? It's a APFS volume so it's not mounted in El Capitan. I just want to Zap OC from this drive, but it seems impossible since you can't boot OCLP when it's installed. It a SATA HD is it advisable to Hot-Swap the drive? I mean boot into Monterey and then connect the SATA Drive?

Can I Zap OC when this drive or do I have to re-format it?

All the Best
Dave

 

[Macschrauber]

you can also use the ESP tools in my package to mount the ESPs and delete the content. Those are FAT32 and can be read by older OS'
https://forums.macrumors.com/thread...es.2333460/page-4?post=32055801#post-32055801

 

[LookToWindward]

Thanks, I'll have a look tomorrow

 

[LookToWindward]

Will your tools allow access it a APFS drive? It's running El Capitan which doesn't support APFS...

 

[Macschrauber]

Will your tools allow access it a APFS drive? It's running El Capitan which doesn't support APFS...

no, to zap the bootloader you will just need to mount the Efi System Partition.

after deleting the remains of OCLP bootloader you will need to re-bless your current OS.

with a bootscreen GPU call the boot picker by holding cmd-key on startup and select your El Cap drive while holding the ctrl-key.

For those basics: https://dortania.github.io/OpenCore-Legacy-Patcher/BOOT.html

just replace (in your mind) the EFI Boot with your El Cap boot drive.

time to do more reading in the OCLP documentation to get a better understanding of the basics ;-)

 

[LookToWindward]

I've booted into El Capitan and mounted the EFI of the drive with MountEFI.

Inside it I see:

EFI folder
OC folder

System folder
Library folder
CoreServices folder
boot.efi
contentFlavour
contentVisibility

Now do I delete the OC folder? What about the System Folder?

 

[Macschrauber]

you can completely delete all whats inside the Efi System Partition.

The System folder of OCLP just mimics the MacOS to load the .efi of the bootloader

 

[LookToWindward]

Deleted the files (Trashed and Empty Trash), so the EFI folder is completely empty now

There are just two empty folders (EFI and System) in the Partition.

 

[LookToWindward]

Well that didn't work! When I booted with option key it showed the (1) OC drive, but as soon I selected it, it froze up.

I've given up and reformatted it

 

[Macschrauber]

Well that didn't work! When I booted with option key it showed the (1) OC drive, but as soon I selected it, it froze up.

I've given up and reformatted it

so you did something wrong, possibly more than one ESP with OpenCore or you just did not delete the files.

 

[LookToWindward]

I left the empty folders EFI and System in the EFI Partition

 

[Macschrauber]

I left the empty folders EFI and System in the EFI Partition

empty folders will not load a bootloader, anyway, as you wiped the disk we cannot see what was wrong.

 

[LookToWindward]

Yes, thanks for your help, I appreciate it