Dual boot MacPro 5.1 issues after Linux re-install

[Calab]

I have a Mac Pro 5.1 system. It uses a Xeon E5 and has 48GB of memory and has a metal compatible Radeon video card. I was successfully booting between MacOS 15 (Sequoia) and Mint Linux using OpenCore and rEFInd.

Today, I decided to replace the Mint Linux with Kubuntu. I made a backup copy of the EFI partition. Next, I booted off of the Kubuntu USB stick and deleted the Mint Linux partition. Finally, I tried to install Kubuntu. The installation stalled around 90%, so I rebooted the machine. I still get the OS selection screen that rEFInd provides, but I cannot boot into MacOS any more. I get the Apple logo and then nothing else happens. I have restored the contents of the EFI partition but it has made no difference.

So far, I have not made any changes to the MacOS partition at all.

Does anyone know how I could get my system booting MacOS again?

 

[MacsBug]

Hi Caleb,

This is something I never thought of doing.. kudos to you for doing this...

Let me ask a few questions to make sure I understand the proper procedure... And then some other questions.

When this is working properly, when you boot the Mac... you should get the rEFInd boot screen to select between Mac or Linux. If you select macOS then you get the OCLP boot screen? Is this the proper proceedure?

Are you getting the rEFInd screen or just going straight to the Apple Logo?

How did you copy over the EFI files? Did you boot from another drive?

After copying over the old EFI files, did you then bless the EFI partition?

Are you able to boot from the recovery partition by holding Command R at boot?

Have you tried to hold down the Option key to see if you can see the OCLP boot loader?

 

[Calab]

Hi Caleb,

This is something I never thought of doing.. kudos to you for doing this...

Let me ask a few questions to make sure I understand the proper procedure... And then some other questions.

When this is working properly, when you boot the Mac... you should get the rEFInd boot screen to select between Mac or Linux. If you select macOS then you get the OCLP boot screen? Is this the proper proceedure?

Are you getting the rEFInd screen or just going straight to the Apple Logo?

How did you copy over the EFI files? Did you boot from another drive?

After copying over the old EFI files, did you then bless the EFI partition?

Are you able to boot from the recovery partition by holding Command R at boot?

Have you tried to hold down the Option key to see if you can see the OCLP boot loader?

At this point I abandoned the Kubuntu install and installed Mint Linux. It is working. I currently get three options on the rEFInd screen when I power on the machine: "EFI", "Sequioa" and "Mint Linux". Choosing "EFI" just gives me a black screen. Choosing "Sequoia" gives me an Apple logo, but no progress bar. Choosing "Mint Linux" boots to Linux without any issues.

My drives are set up as, sda1 = 200mb EFI, sda2 = Sequoia installation, sda3 = Mint Linux installation, sdb1 = Free space, sdb2 = HFS+ data partition (Where I copied EFI to), sdb3 = Free space.

I do not have a Sequoia USB stick to try and reinstall from. I do not have an installation DVD. I have a Windows 11 PC with VMWare patched for MacOS, Mint Linux PC, an OLD Mac Mini running OS 10.6 (I think). I do have a copy of the InstallAssistant for Sequioa but no ISO/DMG file that I can use in VMWare.

To answer your questions...

When working, I would get the rEFInd boot screen. Choosing Mint Linux would book Linux. Choosing Sequoia would boot Sequoia. There were no intermediate screens.

I am getting the rEFInd screen.

Before I did anything, when the machine was working properly, I booted to Linux and copied all the files from the EFI partition to a directory on a second drive in the computer.

I don't know what you mean by "bless the EFI partition".

If I hold Command-R I just get the Apple logo and nothing else happens.

If I hold Option I don't see any reference to the Open Core Legacy Patcher.

One thing I need to check more is leaving the computer sitting when I get the Apple logo. I believe that when I get it, the machine eventually restarts after a few minutes.

Thanks for the reply!

 

[MacsBug]

Hi Caleb,

The EFI files should be on sda1. You shouldn't see the EFI in the rEFInd screen if this is where the files are located.


I havent used rEFInd in about 5 years, so I am going by my notes that I saved.

The Bless command I think was only needed if you use a customized boot screen rather than the default screen.

 

[Calab]

Just to confirm... The computer does restart on it's own after about five minutes when I am stuck at the Apple logo or the blank screen.

 

[MacsBug]

I believe that this is due to the computer looking for the proper boot files on sda1 and not finding them.

 

[Calab]

So, I found an ISO for Sequoia 15.2 on the internet and used that to set up a VM. Using that I was able to create a Sequoia 15.6.1 installer USB stick.

I can boot the USB stick and choose the EFI boot option. I get the rEFInd menu from the hard disk and can boot my Sequoia installation from the hard drive.

Now to figure out how to fix the OCLP on the hard drive.

 

[Calab]

Finally got it fixed...

I ended up copying my config.plist and the ext4 driver from my broken EFI partition. Then I deleted the EFI folder from the partition. Next I copied the EFI folder from the USB installer to my EFP partition on the hard drive. Finally I put my config.plist into the new OC folder, and ext4 driver into the Drivers folder.

Now I get EFI, Sequioa and Mint Linux as boot options when I turn on the machine, and Sequoia and Linux both work. I'm not sure why EFI is there.

 

[Calab]

and, FYI... Mint Linux appears to work right out of the box on my Mac Pro. Kubunutu did not, nor did Elementary OS.