Resolved How do I install the EFI on non-bootable Mac?

[superlativo]

Mac Pro 5.1
SSD #1 High Sierra / Monterey
SSD #2 Windows 10
OCLP 1.0.1
EFI (Macbook Air) Yes, I'm a loser

I wanted to update to Sonoma and created the USB on my Macbook Air. I forgot in OCLP to select Mac Pro and created the USB for the Macvook Air. So I upgraded my Mac Pro with the efi for the Macbook Air. Yes I am stupid.

Currently, the forbidden sign appears in the boot picker if I select High Sierra or Monterey, but if Windows 10 starts, it is fully operational.

I booted into recovery using my Monterey USB (this one is for Mac Pro 5 1 😅) to get to Terminal and tried copying the two EFI folders (EFI and System) from the USB to the EFI on the main partition but it didn't work.

Can I solve it from Windows 10 on my Mac Pro or using my Macbook Air?

I hope you can help me because I am lost.

Thanks in advance.

 

[organicCPU]

As I don´t know the Mac Pro 5.1 and never fiddled around with OpenCore Legacy Patch this might not help much.
Please be aware that my advice could also do more harm, if you don´t understand what you´re doing. Only use the commands, if you are sure, that they make sense in your special situation.

First, did you try Internet Recovery (Option-Command-R on Startup)?:

Use macOS Recovery on an Intel-based Mac

Learn how to use macOS Recovery on an Intel-based Mac.

support.apple.com

If Internet Recovery doesn´t work, try using a working Thumb Drive installer containing Mac OS X 10.6 Snow Leopard to OS X 10.11 El Capitan or the original installer DVDs.

If those preferable methods won´t work and you have another Mac to setup your SSD#1, then you can try the following Terminal commands to get the EFI back:

- To get an EFI back to you startup volume, you´ll need an EFI partition:

# list partitions:
$ diskutil list

# If EFI partition doesn´t exist, create a mount point:
$ mkdir /Volumes/efi

# Mount the EFI partition at the mount point:
$ sudo mount -t msdos /dev/disk0s1 /Volumes/efi

- To write the EFI back on the partition:

# Write EFI disk image (efi.binary) back to EFI partition:
$ sudo dd if=efi.binary of=/dev/disk0s1 bs=409600

# Repair Volume:
$ diskutil repairvolume disk0s1

- Usually BEFORE you´re experimenting with efi, you´ll make a backup of the original one:

# Backup EFI partition to EFI disk image (efi.binary):
$ sudo dd if=/dev/disk0s1 of=efi.binary bs=409600

In the commands above efi.binary means the full path to the DiscImage containing the EFI, this can be different for you, e.g. ~/Documents/MyEFIimageFile.dmg or something else. Make sure to use the correct path. With /dev/disk0s1 it´s the same, that it can differ on your system. Be cautious to take the right partition from the diskutil list command, especially when working from another functioning Mac or you can end up with two corrupted Macs.

If you don´t have access to the right EFI, google for it. There are several Github pages that host them.

To attach the SSD#1 drive to another Mac, boot the MP in Target Disc Mode while pressing the 'T' key. Then attach the MP with a Thunderbolt cable to the working Mac. Alternatively you can deinstall the drive an attach it directly to another Mac.

Windows or Linux might work as well to do the setup, but I´ve never tried that.

After that, try to install macOS again by the suggested methods.

Maybe the wrong OpenCore Legacy Patch needs other steps to get reverted and there might be other MR members that can help you with that.

Good Luck!

 

[superlativo]

Thank you very much @organicCPU for your detailed explanation. Last night after writing the query here, I thought I would do a test. I made a third container on SSD#1 and installed Monterey on it. I thought that not having a correct EFI it would not start at the boot point. To my surprise, after the installation restarts the entire process was carried out without problems. Once in Finder I downloaded OCLP and was able to create and install the correct EFI for the Mac Pro 5.1.

But a problem remains. In bootpicker, only the newly installed Monterey and Windows 10 start. Both High Sierra and the old Monterey still have the forbidden symbol when trying to start them.

I attach the screenshot of my partitions*. I installed EFI for Mac Pro 5.1 on the disk0s1 partition. To make sure I checked the date and time of the files. It was right. As you can see in my list of partitions, I have three EFI on other disks because they previously housed some macOS, but with the purchase of the SSD they became storage and I never knew how to delete them. They have not given me any problems either and since they are not macOS disks I think that EFI should not affect them. Although it would probably be best to eliminate them.

Any idea why, even with the correct EFI, the prohibited symbol still remains on older macOS?

* NOTICE: in the partitions you will see Sonoma but it is yesterday's functional installation of Monterey. I named it Sonoma to differentiate it from the old Monterey.

 

[superlativo]

I wanted to try resetting NVRAM (command + option + P + R) and it was a disaster. Now you just go into Windows 10 and do it directly. Without showing the bootpicker.

Now not even the restore boot (cmd + R) works. Windows 10 also starts. So the solution I did of installing Monterey on a new partition I can no longer do. I don't have access to any macOS. Total disaster.

The bootpicker also does not appear when pressing the Option key. Even if I have the Monterrey USB with OCLP on.

What I can do?

 

[organicCPU]

I agree with you, that EFI won´t matter for booting. So I guess that your macOS Monterey (Sonoma) is broken somehow. To get some more info about the APFS volumes, you can use this:

$ diskutil ap list

There is a snapshot on /dev/disk2s5s1. Maybe the snapshot is broken and prevents booting macOS Monterey (Sonoma). Snapshots can be deleted if you are sure it doesn´t contain important changes that shouldn´t get lost.

The following part I wrote after your NVRAM reset:

Did you backup NVRAM content before? It seems that you deleted your boot-args. Some of the boot-args probably were defined by by Bootcamp installer and some by OCLP. If they´re gone you could define them manually. Usually in a more complex setup, you should backup the NVRAM before resetting it:

# For plain text
$ nvram -p > ~/myNVRAM.txt

# For XML
$ nvram -xp > ~/myNVRAM.xml

You can add boot-args parameters like this:

# To define another boot partition use:
sudo nvram boot-args="rd=disk0s4"

Maybe you can still boot into Recovery Partition (Cmd+R) or try to use Internet Recovery or a Thumb Drive Installer.
If that works, you can try to setup the missing boot-args or probably need to start over (install macOS, install Boot Camp, install OCLP).

 

[superlativo]

Thank you very much @organicCPU. I didn't make a backup of the NVRAM because I followed another thread and they didn't comment on that. So I screwed up again.

How I had lost the OCLP boot picker I remembered that the ATI Radeon RX560 card lost the native boot picker so I mounted the original ATI Radeon and my old Apple Cinema Display and I have partial access to macOS again. I explain.

Native boot picker:

macOS Big Sur-Datos > Monterey (Partial boot. It remains stuck at 35% of the progress bar).
EFI Boot > Windows 10 (Perfect boot).
EFI Boot > Shows the OCLP boot picker.
macOS Sonoma > New Monterey but shows a kernel panic screen and It instantly starts but also stays at 35% of the progress bar).
macOS High Sierra > Perfect boot.

OCLP boot picker:

Windows > Windows 10 (Perfect boot).
macOS Big Sur-Datos > My old Monterey (No boot. Prohibited symbol).
macOS Sonoma > The new Monterey that I installed yesterday and booted without problems but today it does not start. Probably due to the NVRAM reset.
macOS High Sierra > High Sierra (No boot. Prohibited symbol).

Current status of bootable OS:

Windows 10 and macOS High Sierra (only on native boot picker). Monterey recovery partition with cmd + R and also the bootable USB Monterey.

At this point, I don't want to play anymore 😅

What can I do to reset boot in the OCLP boot picker and remove the prohibited symbol for my old High Sierra and Monterey? I want to go back to my RX560 card and 4K monitor.

 

[superlativo]

The problem started when installing OCLP 1.0.1. So I tried 0.6.8 and now everything works again. So the problem is having installed 1.0.1 to test Sonoma but for now I will stay in Monterey where I have no problems. I thought it was always better to use the latest version of OCLP.

@organicCPU Thank you very much for your great help!

 

[organicCPU]

So I tried 0.6.8 and now everything works again.

Glad to hear that you managed to get things back to working state.

I think you´ve learnt much (the hard way). Nonetheless, it´s always a good idea to have a backup of EFI and NVRAM.

 

[superlativo]

Glad to hear that you managed to get things back to working state.

I think you´ve learnt much (the hard way). Nonetheless, it´s always a good idea to have a backup of EFI and NVRAM.

Exact! He who does nothing is not wrong.

A forum like this helps a lot to be accompanied and feel that sooner or later you will end up solving it. That said, thank you very much @organicCPU for your gorgeous help!

 

[Macschrauber]

Backing up the text the nvram cli tool gives is in no way a backup of the nvram content. Its just a little part of what some variables return.

The tool in my signature does a real backup of the full firmware (and the included nvram volume). Plus does a load of checks and readouts.

With this dump you can even repair a board with a failed firmware chip. By replacing it with a preprogrammed new chip, when the previous one failed physically or logically.