OpenCore install on existing partition?

[unclemiltie]

I have a disk with multiple partitions on it with both Big Sur and Monterey install that I've been using to test out different installs on different hardware. Is there a way to use OpenCore patcher on those disks without having the tool erase all of the partitions on the disk? (e.g. have it just install the right patches on a bootable partition that already exists with a Monterey installer or the other partition with the Big Sur installer?

(the disk also has a bootable High Sierra, Mojave and Catalina on them using DosDude's patcher and those are just fine)

 

[avz]

I have a 13 inch Mid 2012 MacBook Pro and I boot natively Windows 11 Pro(BootCamp), Mojave, Catalina, Big Sur, Monterey(separate volumes under the same APFS container).

I believe the answer to your question will depend on which Mac do you have and what is the last officially supported macOS? If you have an old Mac the advice is usually not to mix together installations patched by a dosdude1's patcher and the OCLP.

 

[unclemiltie]

I'm not asking about installing and booting multiple OS versions on the system, I'm talking about having an external disk that has bootable partitions on it for installing High Sierra, Mojave, Catalina, Big Sur and Monterey on it. Then I can carry it around to multiple sytems and install whatever version I like on that system.

I've got HS, Mojave and Catalina working since the DosDude patchers give you enough to get all of the machines working. But OCLP insists on rebuilding the entire disk (erasing all of the partitions) when you want to change machines.

I'd prefer telling it "here's the Monterey partition, fix it for iMac 12,2" so that I don't need to erase the disk and take the time that it takes to generate a new boot disk from the installer.

 

[avz]

From what I understand there is only one EFI partition per drive as well as NVRAM variables so this is why you'll have to rebuild OCLP every time you use it on a different Mac. This is also where this advice comes from that you might have overlooked in my initial reply.

If you have an old Mac the advice is usually not to mix together installations patched by a dosdude1's patcher and the OCLP.

The root patches on the other hand can be applied independently from each other on each macOS volume/partition.

 

[gilby101]

I'd prefer telling it "here's the Monterey partition, fix it for iMac 12,2" so that I don't need to erase the disk and take the time that it takes to generate a new boot disk from the installer.

For a bootable installer, it is the EFI partition which must be changed. And the changes vary for different macOS versions and different Mac models. As @avz says.

OCLP is designed to make it as easy to use as possible. It is not designed for complex scenarios like you want with multiple macOS versions targeting multiple Mac models.

 

[unclemiltie]

Thanks, I figured that it needed different stuff. I was hoping that I could maybe just point the patcher at the right partition and it woulid fix up the EFI as well as the boot partition to save me time.

But alas, that's not looking possible and I'll have to make unique flash drives every time I want to swap machines (I've bot about 5 different variants)