I screwed up trying to revert from Opencore

[henkebarn]

I found my 2009 Mac mini in a box and thought I'd experiment with it. I used Opencore Legacy Patcher to install Monterrey and it worked. However, Wifi didn't work as expected and I also had some graphic issues. So I thought that I'd best revert to stock.

I fetched a El Capitan bootable USB drive and fired it up. I started with erasing the system disk and thought that I'd be ok to install El Capitan. But nope!

Obviously the Opencore patch has done something (probably expected) with my Mac and now this is the situation:

1. When I do a normal boot I get the three options in the first picture:
   1. BootKicker.efi - selecting this gives me black screen
   2. OpenShell.efi - selecting this gives me some kind of terminal view, but that's way out of my competence level to understand
   3. Reset NVRAM - does exactly that, but nothing changes
2. When I boot with the following commands, it's just like doing a normal boot. I get to the same screen as in the previous list:
   1. cmd+alt+shift+R
   2. cmd+R
   3. cmd+shift+R
3. When I hold alt while booting (with a bootable El Capitan stick) I only get the Opencore EFI boot option, as the second image. Selecting that takes me to (1) again.

So yeah, I feel stupid. I know in retrospect that I shouldn't have erased the disk. Is there any way out of this?

 

[BrianBaughn]

When you "started with erasing the system disk" did you erase the entire disk or just the System volume?

 

[henkebarn]

When you "started with erasing the system disk" did you erase the entire disk or just the System volume?

Can't remember, to be honest. I guess you're implying that I have erased the recovery partition?

 

[BrianBaughn]

Can't remember, to be honest. I guess you're implying that I have erased the recovery partition?

No. I was thinking that you didn't erase the EFI partition that contains Opencore.

 

[henkebarn]

No. I was thinking that you didn't erase the EFI partition that contains Opencore.

Aha. Yeah, I should've if I erased the entire disk, right? But now I can't even get into recovery or boot from anything other than what's shown in the images. Weird, to me at least.

 

[BrianBaughn]

Erase it from the bootable El Capitan USB.

If OCLP and Monterey aren't a good fit you can always try dosdude1's patchers to get a decent macOS version up to Catalina.

 

[henkebarn]

Isn't it pretty weird that the 2(!) internal drives in the Mac mini aren't showing up when I hold option as I boot?

 

[Nappysloth]

bump

I have the same problem. Did you already find a solution @henkebarn ?
No matter how I start the MacBook (key combination, etc.), I always get to this "start page".

I need help! asap

 

[henkebarn]

bump

I have the same problem. Did you already find a solution @henkebarn ?
No matter how I start the MacBook (key combination, etc.), I always get to this "start page".

I need help! asap

Yes I fixed it. The problem was probably that the bootable usb I made was made on a computer that was too new to support the OS i was trying to install. So I used an older computer to make a new installer with a system that both the computers could install and then I could boot while holding option and get started.

Hope that helps!

 

[lordos2]

Yes I fixed it. The problem was probably that the bootable usb I made was made on a computer that was too new to support the OS i was trying to install. So I used an older computer to make a new installer with a system that both the computers could install and then I could boot while holding option and get started.

Hope that helps!

I had the same problem on a macbook pro late 2011 8,1 I installed ventura with opencore and and had the same result you had , so I had a dosdude catalina usb stick it has a copy of disk utility on it and I used it to do a complete format including the efi partition and it got rid of opencore, I reinstalled catalina and used the option on the stick to run in a time machine backup, it will also allow a backup from a start up disk from external.

 

[eaglebear]

I am stuck in same point friends, don't know what to do, really appreciate your help!:

 

[paardenkapper]

If you're fine with losing all data on your harddrive you could just boot up with an installer pendrive and use the Disk Utility to wipe your hd/ssd and remove all created partitions. Then you should be able to install vanilla macOS again.

 

[Asarayne]

Hey everyone!
So I kinda messed up the same way, but also worse. I pulled the drive and cleared it using disk part on a windows os. Left it as uninitialized. Put it back in my mid 07 imac, and now it only boots to a black screen, doesn't let keyboard inputs for overrides, so I can't boot of my Yosemite install usb
Can anyone shed some light on this for me?

 

[anshuvorty]

Hey everyone!
So I kinda messed up the same way, but also worse. I pulled the drive and cleared it using disk part on a windows os. Left it as uninitialized. Put it back in my mid 07 imac, and now it only boots to a black screen, doesn't let keyboard inputs for overrides, so I can't boot of my Yosemite install usb
Can anyone shed some light on this for me?

Yeah, I think by doing this, you actually nuked the hidden recovery partition that allows you to boot into the recovery environment and reinstall macOS.

Also, by leaving it as uninitialized, that means that there is no partition table on the hard drive, so the Mac doesn't know how to boot to it.

At this point, you will need to load a version of macOS onto the hard drive and then transfer it back into the original Mac, I believe.

I think you will need to do the following:

1. connect the hard drive to another Mac using an external adapter
2. boot to the recovery environment on the Mac
3. open disk utilities
4. hopefully the hard drive shows up
5. then, erase the hard drive and format it with APFS by clicking the "erase" button - https://support.apple.com/guide/dis...at-a-storage-device-dskutl14079/22.0/mac/13.0
6. then, install macOS Ventura onto the hard drive
7. once installed, shut down the Mac and remove the hard drive from the external adapter
8. connect the hard drive back to the original Mac
9. hope it boots!

 

[Asarayne]

Yeah, I think by doing this, you actually nuked the hidden recovery partition that allows you to boot into the recovery environment and reinstall macOS.

Also, by leaving it as uninitialized, that means that there is no partition table on the hard drive, so the Mac doesn't know how to boot to it.

At this point, you will need to load a version of macOS onto the hard drive and then transfer it back into the original Mac, I believe.

I think you will need to do the following:

1. connect the hard drive to another Mac using an external adapter
2. boot to the recovery environment on the Mac
3. open disk utilities
4. hopefully the hard drive shows up
5. then, erase the hard drive and format it with APFS by clicking the "erase" button - https://support.apple.com/guide/dis...at-a-storage-device-dskutl14079/22.0/mac/13.0
6. then, install macOS Ventura onto the hard drive
7. once installed, shut down the Mac and remove the hard drive from the external adapter
8. connect the hard drive back to the original Mac
9. hope it boots!

Honestly, that's exactly what I thought I was gonna have to do, it will have to wait till tomorrow since my macbooks are not at my shop lol, and I'm not using my Mac pro to do this.(it runs my shop music)
Thanks for the heads up, reddit has been no help.
Seriously thank you.

 

[allan.nyholm]

@Asarayne could you put the disk back in to the Windows PC and type the usual commands one by one
diskpart
list
select disk your disk e.g select disk 1 or select disk 2
clean
convert gpt

You can try creating a complete partition in an NTFS format by typing this after having typed convert gpt command

create partition primary

format=NTFS label=INSERTSHORTNAME quick

After this you could use
assign to assign a drive letter to the newly formatted drive.. it's not useful for your purpose in macOS, but I'm just adding it here anyway.

You still ought to get a hold of the Internet Recovery to then format your now uninitialized hard drive.

Use Disk Utility to format into a JHFS+ or directly to an APFS file system.

I would however just try the JHFS+ first.

macOS automatically converts your JHFS+ drive to APFS anyway.

Try again using Internet Recovery - Google the special keys to get access to Apple's servers. Use an Ethernet cable.

Unless I haven't read properly. Then like all the other times, I take it all back

 

[Asarayne]

@Asarayne could you put the disk back in to the Windows PC and type the usual commands one by one
diskpart
list
select disk your disk e.g select disk 1 or select disk 2
clean
convert gpt

You can try creating a complete partition in an NTFS format by typing this after having typed convert gpt command

create partition primary

format=NTFS label=INSERTSHORTNAME quick

After this you could use
assign to assign a drive letter to the newly formatted drive.. it's not useful for your purpose in macOS, but I'm just adding it here anyway.

You still ought to get a hold of the Internet Recovery to then format your now uninitialized hard drive.

Use Disk Utility to format into a JHFS+ or directly to an APFS file system.

I would however just try the JHFS+ first.

macOS automatically converts your JHFS+ drive to APFS anyway.

Try again using Internet Recovery - Google the special keys to get access to Apple's servers. Use an Ethernet cable.

Unless I haven't read properly. Then like all the other times, I take it all back

I appreciate your reply, but yes you did kind of read wrong, since the imac won't even let any key combos happen. It just sits on a black screen when I hold any, and if I don't it goes to a black screen with a ? Folder. Which I know means it can't find an os, or efi folder.
I've brought one of my macbook pros to work today, so I'm just gonna pull the drive(what a pita for this model) and shove it in the macbook and do a reinstall of Yosemite since that is the customers original os.

All this is brought on cause opencore keeps unexpectedly quitting its Gui on his actual imac, not mine, and when I try to run it from terminal, I get an illegal instruction 4 return.
So I was like whatever I'll downgrade my imac, put on yos, and see if i get the same behaviour on my imac, to see if his is dying and not just a very old borked over the years os install.

Sorry for the wall of text.

 

[allan.nyholm]

welp, I didn't know it was possible to get to that stage.

I might have screwed up something myself. I'm personally unable to get to the Apple Diagnostics on my Mac. Just errors out. Or at least it used to. I gave up trying a while back.

just a comment on a situation I've had

The times I haven't been able to get the EFI boot picker to appears is because I've used a non-Apple keyboard. Even a wired non-Apple keyboard. I think I've tried most combos. At some point I just give in and plug in the Apple keyboard that came with my iMac and all is good again.

just a comment on a situation I've had

 

[Asarayne]

welp, I didn't know it was possible to get to that stage.

I might have screwed up something myself. I'm personally unable to get to the Apple Diagnostics on my Mac. Just errors out. Or at least it used to. I gave up trying a while back.

just a comment on a situation I've had


just a comment on a situation I've had

Good to know. I have tried a regular keyboard on not any of the aluminum mac ones. But I have to admit, I don't which keys are which on a regular keyboard. Like the windows key which one on a mac keyboard is it?
Sorry if that's a super stupid question lol.
Im trying to learn more about Mac so I can more confidently fix ones that are brought into my store.

 

[allan.nyholm]

Good to know. I have tried a regular keyboard on not any of the aluminum mac ones. But I have to admit, I don't which keys are which on a regular keyboard. Like the windows key which one on a mac keyboard is it?
Sorry if that's a super stupid question lol.
Im trying to learn more about Mac so I can more confidently fix ones that are brought into my store.

I've read somewhere that it's the Ctrl key that's the equivalent to the Option key on the Mac, but that hasn't worked at all for me. Neither has using the Alt key in place of Option. Then it's either the left or right keys to press.

So that's a few options to go through. My cheap Windows/PC keyboard might just be the weird one. It does however only have a USB dongle that connects it. I have not tried any wired Windows / PC keyboards for this.

 

[Asarayne]

I've read somewhere that it's the Ctrl key that's the equivalent to the Option key on the Mac, but that hasn't worked at all for me. Neither has using the Alt key in place of Option. Then it's either the left or right keys to press.

So that's a few options to go through. My cheap Windows/PC keyboard might just be the weird one. It does however only have a USB dongle that connects it. I have not tried any wired Windows / PC keyboards for this.

Ah fair fair.

 

[anshuvorty]

I've read somewhere that it's the Ctrl key that's the equivalent to the Option key on the Mac, but that hasn't worked at all for me. Neither has using the Alt key in place of Option. Then it's either the left or right keys to press.

So that's a few options to go through. My cheap Windows/PC keyboard might just be the weird one. It does however only have a USB dongle that connects it. I have not tried any wired Windows / PC keyboards for this.

The Windows Key is the Command Key on an Apple Keyboard.

 

[Asarayne]

The Windows Key is the Command Key on an Apple Keyboard.

Thank you!

 

[allan.nyholm]

The Windows Key is the Command Key on an Apple Keyboard.

yup, that one I got. It was just the boot picker thing I could never get to with the keyboard of mine

 

[DeltaMac]

Your best choice will be a wired USB keyboard. You will often be frustrated if you try the resets with a wireless keyboard
If you don't have a Apple-brand keyboard, the keys that you want are Alt+Windows+P+R.
Apple keyboard keys will be Option+Command+P+R
That keyboard shortcut is to reset NVRAM. You should make sure that the iMac is shut off. (Press and hold the power button for 5 seconds or more, or simply unplug the power cord).
Press and release the power button, then immediately hold the Opt+cmd+p+r
You should get a boot chime after a few seconds. Continue to hold the same 4 keys until you hear the boot chime 2 more times. Then release keys, but continue to hold the Option key (Windows key on a PC keyboard)
You would have your bootable USB innstaller inserted, which should appear on the screen within about 15 seconds.
If you don't see your external bootable, reach around and unplug that drive, then plug back in. Wait another few seconds for the drive to appear. If you still don't see that drive, then it is likely not made correctly. Making a bootable installer for a Mac, using a Windows PC often does not work. The most reliable method is to a use a Mac to make the bootable installer.