Can't get grub to boot my OpenCore MacOS drive - SOLVED

[Xyla]

All over the internet I have found people saying it's so easy to add a macOS/OpenCore entry to your grub menu...

menuentry "macOS Ventura" --class macosx {
insmod chain
insmod fat
insmod part_gpt
insmod search_fs_uuid
search --fs-uuid --no-floppy --set=root 67E3-17ED
chainloader ($root)/EFI/OC/OpenCore.efi
}

This does not work for me. I've also tried dozens of variations of basically the same thing but it never works. Every time I get the error:

error: file /EFI/OC/OpenCore.efi not found.

I don't understand. Why does this method work for everyone but me?

I can boot the drive by selecting it in the BIOS, but I just can't get grub to work. And before anyone suggests using OpenCore boot picker to select my Linux drive instead... yes, that's how I used to have it and it does work, but it also causes tons of ACPI errors when Linux boots, which I don't like. I want to use grub as my master OS selector to avoid that, and from everything I've read, it should not be a problem.

If anyone could help, I would greatly appreciate it.

 

[Yomiro]

I dont chainboot opencore, so I cant test it. But can you test/try something.

for $root. Can you find the EFI partition of opencore?? then try setting root as (hdX,gptX)

Assuming you are using a separate drive for MacOS. Without knowing how your disk, partitions and configuration is set. It's very hard to figure out what's wrong with your boot.

Your root seems to be a disk. and not a partition.

Mine looks like this

sdg4   ext2   1.0   boot    XXXXXXX-4714-41ce-8c7a-YYYYYYYY     1.7G     9% /boot

But, if you can EFI boot from BIOS into OpenCore. Then you should be able to use grub to boot into that **partition**

 

[Xyla]

I dont chainboot opencore, so I cant test it. But can you test/try something.

for $root. Can you find the EFI partition of opencore?? then try setting root as (hdX,gptX)

Assuming you are using a separate drive for MacOS. Without knowing how your disk, partitions and configuration is set. It's very hard to figure out what's wrong with your boot.

Your root seems to be a disk. and not a partition.

Mine looks like this

sdg4   ext2   1.0   boot    XXXXXXX-4714-41ce-8c7a-YYYYYYYY     1.7G     9% /boot

But, if you can EFI boot from BIOS into OpenCore. Then you should be able to use grub to boot into that **partition**

No, that UUID is for the partition... the EFI partition. And that was exactly my problem...

I found out today that MacOS Disk Utility creates the same UUID for all EFI partitions: 67E3-17ED. So the reason grub couldn't find OpenCore.efi was that using the UUID was useless, because I had 5 drives with EFI partitions using the same UUID!!!

I solved the problem by deleting my EFI partition on the OC drive, and creating a new one in it's place with gparted on Linux... then copying OC back to the new EFI partition. Since it has a unique UUID now, grub is able to find it just fine.

 

[Yomiro]

Good to hear. Out of curiosity are you using MBR partitioning?