MP 1,1-5,1 Mac Pro 5,1 > OpenCore Legacy Patcher > Lost access to Mojave

[5comma1]

Greetings!

Hardware • Software
• Mid 2010 Mac Pro 5,1
• OCLP 0.6.1
• Monterey 12.6.3
• flashed RX 580 Pulse
• two Dell 27” displays + one troubleshooting display


OpenCore Monterey allows me to use updated versions of apps unsupported by Mojave, but Mojave is my safety-net home base.


THE PROBLEM
Unable to boot into Mojave


WHAT LED TO THE PROBLEM
- both Mojave and OpenCore Monterey were running fine for a month.
- only issue was “Incompatible Disk” error (screenshot). Began troubleshooting this.
- learned error message might be because Mojave boot disks were formatted using Monterey.
- Mojave is on one 2TB SSD and Mojave Bootable Backup is on another 2TB SSD. (screenshot)
- both Mojave SSD’s are partitioned. Half for Mojave, half for storage.
- both drives were formatted in Monterey > APFS/GUID. (didn't have Mojave at the time)
- decided to wipe Mojave Bootable Backup and reformat while running Mojave.
- I was comfortable wiping Mojave Bootable Backup because I still had the primary Mojave drive.
- Mojave Bootable Backup Disk Utility “erase” failed.
- went into Monterey to erase Mojave Bootable Backup in Disk Utility; succeeded.
- attempted to go back into Mojave and do necessary cloning using SuperDuper.
- unable to boot Mojave!!! No boot picker > no login window.
- one display shows one of my personal desktop photos… the other display remains black.
- when connecting a 3rd display, I can see the boot picker and boot OpenCore Monterey. (screenshot)
- when connecting a 3rd display, I can also see the Mojave boot picker, but get the Prohibitory Symbol when selecting it.



QUESTIONS
1) Why did wiping the Mojave Bootable Backup drive make the primary Mojave drive inaccessible?


2) Why am I able to see the boot picker on the troubleshooting display but not on the two displays I use every day?


3) How can I access Mojave again without doing a full reinstall?



I posted over on the OpenCore Patcher Paradise Discord a few days ago but the volume of inquiries there is so high it’s tough to get help. Thought I’d try here. Thanks much!

 

[haralds]

The reason why you saw the "incompatible disk" message for the Monterey partition is because it uses a version of APFS Mojave does not understand. Just ignore the message. I have a similar config and it is unavoidable.
OpenCore cannot boot Mojave. You can only boot that from the native boot picker (press Option while booting.)
With a flashed RX580 the boot screen should be visible on one of your standard displays.
Do not manipulate Mojave partitions from Monterery and vice versa.
To try to fix Mojave:
- Try NVRAM reset (CMD-OPT-P-R) and option boot. If that does not work:
- Reinstall: create a standard USB stick install for Mojave and install to the Mojave partition. It should keep your configuration intact. Boot the stick from the native boot picker, not OpenCOre.
To boot back into Monterey, choose EFI on the option boot screen. It will make EFI default, you will need to option boot your way back into Mojave.

 

[5comma1]

Holy Cow!

You may have saved my bacon!

I'll try your suggestions and report back.

Thanks a ZILL for the prompt and thorough reply!! 👍👍👍

 

[Macschrauber]

You can add -no_compat_check to the boot args and better -v too to get verbose text with real error messages and to bypass the Mojave check.

This could get you into Mojave if booted via OpenCore.

 

[5comma1]

The reason why you saw the "incompatible disk" message for the Monterey partition is because it uses a version of APFS Mojave does not understand. Just ignore the message. I have a similar config and it is unavoidable.
OpenCore cannot boot Mojave. You can only boot that from the native boot picker (press Option while booting.)
With a flashed RX580 the boot screen should be visible on one of your standard displays.
Do not manipulate Mojave partitions from Monterery and vice versa.
To try to fix Mojave:
- Try NVRAM reset (CMD-OPT-P-R) and option boot. If that does not work:
- Reinstall: create a standard USB stick install for Mojave and install to the Mojave partition. It should keep your configuration intact. Boot the stick from the native boot picker, not OpenCOre.
To boot back into Monterey, choose EFI on the option boot screen. It will make EFI default, you will need to option boot your way back into Mojave.

The NVRAM reset didn't seem to help... moving on to the reinstall:

A clarifying question, please. The native boot picker has a black background, doesn't it? The picker I'm getting when I boot from the Mojave USB stick while holding option has a gray background (screenshot), then I'm taken to the MacOS Utilities Recovery window (screenshot). Am I barking up the wrong boot picker?

 

[5comma1]

You can add -no_compat_check to the boot args and better -v too to get verbose text with real error messages and to bypass the Mojave check.

This could get you into Mojave if booted via OpenCore.

Hey... just wanted to thank you kindly for your contribution, and for flattering me by thinking for a moment I could decipher and execute what you wrote. It's well beyond my pay grade... but appreciated nonetheless. Thank you! 👍

 

[Macschrauber]

Well, mount the esp with openCore into it, head for the config.plist file and edit the boot-args setting.

Details are here:

OpenCore on the Mac Pro

This guide explains how to use the excellent OpenCore boot loader to install, run, and update the latest version of macOS on the MacPro5,1, resulting in a clean, unaltered operating system just like on a supported Mac.

forums.macrumors.com

 

[haralds]

Hey... just wanted to thank you kindly for your contribution, and for flattering me by thinking for a moment I could decipher and execute what you wrote. It's well beyond my pay grade... but appreciated nonetheless. Thank you! 👍

I have never been able to boot Mojave with OpenCore. Monterey and Ventura work fine.

 

[haralds]

The NVRAM reset didn't seem to help... moving on to the reinstall:

A clarifying question, please. The native boot picker has a black background, doesn't it? The picker I'm getting when I boot from the Mojave USB stick while holding option has a gray background (screenshot), then I'm taken to the MacOS Utilities Recovery window (screenshot). Am I barking up the wrong boot picker?

The grey background on the left image is the correct one the Mac Pro 5,1. You do not get a black boot screen on Mac Pro unless you are in OpenCore.

 

[5comma1]

The grey background on the left image is the correct one the Mac Pro 5,1. You do not get a black boot screen on Mac Pro unless you are in OpenCore.

Ok then, thanks for confirming I had the boot picker background colors backward. Appreciate it! I'll forge ahead and report back. 👍

 

[5comma1]

The grey background on the left image is the correct one the Mac Pro 5,1. You do not get a black boot screen on Mac Pro unless you are in OpenCore.

Thank you! • Thank You • Thank You!

I'm now able to boot into Mojave! I was THRILLED to be able to do that and I immediately re-created my Mojave bootable backup using SuperDuper, and I'm able to boot that as well. I then booted into OCLP Monterey and that still works, too. Fantastic!

The "Incompatible Disk" error still appears, of course— but i'll happily ignore that, as you suggest.

I'm grateful to you and others here who freely share their expertise with strangers like me. Your fix-suggestions may not seem like a big deal to you, but in my world your help made the difference between me not being able to use my Mac AT ALL... and having no idea how to fix it, to being back in the game.

I thank you. I'm grateful. I hope someone shows you a kindness sometime soon.

Cheers!

 

[5comma1]

Well, mount the esp with openCore into it, head for the config.plist file and edit the boot-args setting.

Details are here:

OpenCore on the Mac Pro

This guide explains how to use the excellent OpenCore boot loader to install, run, and update the latest version of macOS on the MacPro5,1, resulting in a clean, unaltered operating system just like on a supported Mac.

forums.macrumors.com

Thanks a lot for the link!

 

[Minghold]

Holy Cow!

You may have saved my bacon!

I'll try your suggestions and report back.

Thanks a ZILL for the prompt and thorough reply!! 👍👍👍

BTW, your Mojave will run a lot quicker from an HFS+ partition than an APFS one, even on an SSD. (So just create such a partition, then clone it using either Get Backup Pro or CCC.)

 

[5comma1]

BTW, your Mojave will run a lot quicker from an HFS+ partition than an APFS one, even on an SSD. (So just create such a partition, then clone it using either Get Backup Pro or CCC.)

Thanks for the tip, Minghold!

 

[Minghold]

Thanks for the tip, Minghold!

BTW, it escapes my memory what was the name of the application that permitted installing/running older versions of the OS from within the newer ones. --You wouldn't know what it was, would you? (I vaguely recall that it wasn't just an emulator or visualizer like Parallels, etc.)

 

[5comma1]

BTW, it escapes my memory what was the name of the application that permitted installing/running older versions of the OS from within the newer ones. --You wouldn't know what it was, would you? (I vaguely recall that it wasn't just an emulator or visualizer like Parallels, etc.)

Sounds like what Open Core does, but in reverse? No... I wasn't even aware anything like that was out there?

 

[Macschrauber]

I have never been able to boot Mojave with OpenCore. Monterey and Ventura work fine.

I do that frequently, last time yesterday. Just add -no_compat_check to config file boot-args list.

 

[cpnotebook80]

I am in the same boat today as I saw that Mojave is not accessible to me at the bootloader screen after successfully installing Monterey on a 2tb NVME. The Mojave is on a 1tb NVME and like to keep it as my goto base. When I do select Mojave on boot, I get a grey circular prohibition icon and system shut down. Will the above codes work?

PS: Decided to let Mojave sail into the sunset and move stuff over to Monterey.

 

[haralds]

[...]

PS: Decided to let Mojave sail into the sunset and move stuff over to Monterey.

Be careful, if your system does not natively support Monterey. If you are using OpenCore or OCLP it is wise to keep a minimum bootable version of the last supported version of macOS on your system. It makes recovering from trouble a lot easier, especially if you only have one Mac.

 

[cpnotebook80]

I do have 3 bootable systems so that helps! But yea I have backups thanks

 

[h9826790]

I am in the same boat today as I saw that Mojave is not accessible to me at the bootloader screen after successfully installing Monterey on a 2tb NVME. The Mojave is on a 1tb NVME and like to keep it as my goto base. When I do select Mojave on boot, I get a grey circular prohibition icon and system shut down. Will the above codes work?

PS: Decided to let Mojave sail into the sunset and move stuff over to Monterey.

If you want to dual boot Mojave and Monterey, you better change the board ID to the iMac Pro board ID.

I believe OCLP default to use the 7,1 board ID, which has no Mojave support.

Using -no_compat_check boot argument may allow the cMP to boot to Mojave with the 7,1 board ID, but the macOS itself won't work properly. e.g. There won't be any HWAccel.

 

[reppresident]

If you want to dual boot Mojave and Monterey, you better change the board ID to the iMac Pro board ID.

I believe OCLP default to use the 7,1 board ID, which has no Mojave support.

Using -no_compat_check boot argument may allow the cMP to boot to Mojave with the 7,1 board ID, but the macOS itself won't work properly. e.g. There won't be any HWAccel.

excuse me, reading this post makes me wonder: is that any benefits from spoof a cMp 5.1 to mac pro 7.1 instead of imac pro? thanks anyway

 

[h9826790]

excuse me, reading this post makes me wonder: is that any benefits from spoof a cMp 5.1 to mac pro 7.1 instead of imac pro? thanks anyway

Yes, the 7,1 has PCIe slot, support PCIe graphic cards by default.

For iMac Pro, the original config should be with an internal monitor, which has its own special Framebuffer. Therefore, using iMac Pro board ID may need extra boot argument to regain some graphic card output ports’ function.

 

[artistef]

I have been running Mojave and Monterey on two SSD's both booting in OpenCore on my 2010 5,1. I first did a manual install of Martin Lo's OpenCore, on my system running Mojave, primarily because I use an unflashed RX580, and wanted a boot screen. I found out about OCLP some months later, and did a Monterey install on the second SSD using it. I then found that I couldn't boot back into Mojave. It turned out OCLP had 'Updated' the original OpenCore EFI on the Mojave SSD. Fortunately I had a copy of the original OC files stored, so while running in Monterey I opened the EFI partition on the Mojave SSD and replaced the OC folder. This fixed the problem and I was able to boot back into Mojave. I also get the Incompatible Disk message, but ignored it as I figured this was probably due to Mojave's unique APFS formatting.

If anyone has any idea how I can run OCLP without it affecting my original OpenCore installation I'd be grateful. At present the only thing I can think of doing is removing the Mojave SSD while tinkering.