Can anyone help with installing open core to install macOS 15 sequoia

Destroyer1976

New Tinkerer
Sep 8, 2025
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1
Queensland, Australia
I need serious help.

I have a 2012 mac pro. I've tried installing open core but no go.

  • Dual 6 core 3.33ghz Intel CPU
  • RX580 AMD Graphics
  • 96GB RAM
On boot up, no screen until sign in. I have the Gop firmware installed to get a boot screen, but I don't get the boot screen.

I'm pulling my hair out trying to get the boot screen going. The machine boots but no boot screen/picker??

Any help would be great.

Duncan
 

phunguss

Active Tinkerer
Dec 24, 2023
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Stillwater, MN
Did you install root patches ? What is Boot Picker Timeout set to? Have you tried it with the GOP option off? Do you have full acceleration (tansparent dock)?
 

Destroyer1976

New Tinkerer
Sep 8, 2025
10
0
1
Queensland, Australia
Did you install root patches ? What is Boot Picker Timeout set to? Have you tried it with the GOP option off? Do you have full acceleration (tansparent dock)?
I've installed OCLP on the mac and made the USB installation and tried installing but no go?? How do I install root patches? How do I set boot picker timeout? I've tried Gop & no Gop firmware. I'm running MAC OS Mojave. I have a transparent dock.
 

phunguss

Active Tinkerer
Dec 24, 2023
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63
Stillwater, MN
Mojave does not require root patches, but Sequoia does. You should be using OCLP 2.4.0 or 2.4.1, either should be fine. There is one gotcha, and that is the USB 1.1 dropped support. To get around that, make sure your installation USB is 2.0 or 3.0 and plug in a USB hub.

Main screen you should be familiar with.
OCLP-01-main.jpg

Your target model should be picked automatically. I assume MacPro 2012 is a MacPro5,1 ? You can always click the "settings" button and get to this and change it. Build tab is where your Boot Picker Timeout is located.
OCLP-03-advanced.jpg

Advanced tab is where you can turn on/off GOP.
OCLP-02-Target.jpg

Last month I created a drive for a friend's 5,1 on my 4,1 upgraded to 5,1 ROM. Here is the bootpicker (all APFS Volumes, Windows was a secondary drive). These are not default icons, I added them to each Volume after installation.
OCLP-04-BootPicker.jpg

Booted into Sequoia. Once you have installed Sequoia, OCLP should pop up and tell you that you are running without root patches and offer to install them for you.
OCLP-05-good.jpg

Hope that helps.
 

Destroyer1976

New Tinkerer
Sep 8, 2025
10
0
1
Queensland, Australia
I'm sorry, I don't know what's wrong with this machine. I upgraded to OCLP v2.4.1. I set the timeout to "10". I tried Gop option on and off. I'm sure I have "enable_gop" installed in the mother/logic board firmware/bios. I have an AMD RX580. It's still booting up blank. I press option when booting, is that the wrong key to press? AAHHH!! PLEASE HELP, everyone says, "It's so easy" well I'm seriously thinking of selling the Mac Pro. I even re-installed my single CPU 3.33ghz CPU tray with 8GB ram on it, and still no difference. The seller of the graphics card said it was made to work with mac's.
 

phunguss

Active Tinkerer
Dec 24, 2023
441
375
63
Stillwater, MN
There is a lot going on in that paragraph. Let's dissect it piece by piece.

"I have enable_gop installed on the mother/logic board firmware/bios".
There is no bios on a real mac. Enable_GOP is a setting inside OCLP to enable non-Mac cards.

"I press option when booting"
This is for a real mac with a real apple compatible graphics card. NOT used with OCLP on a real mac. NOT used on a Hackintosh with Open Core installed. OCLP (Open Core) is your boot picker (what the option does on a real mac). Don't use the option key (with caveat below).

"It's so easy"
Yes it is.

"The seller said it was made to work with mac's"
Not sure what this means exactly. Was it firmware/VBIOS modified? I don't think an AMD RX580 was ever produced in a "Mac Edition" variant. If it was VBIOS modified (I did it on a GTX 770), then it would be considered a real mac graphics card and you could use the Option key at boot. No matter the VBIOS, you should still get the OCLP boot picker. If you are using the Option key, you should see an option for the EFI folder (to start OCLP).

-How long are you waiting at the black screen? It may take 10-30 seconds after the chime for the OCLP boot picker to appear.

-Do you have any other graphics cards to test options with? I think you have another mac because you are changing your USB stick with the OCLP options? Or are you waiting for login, and then you can use your mac to edit the OCLP settings? What drive are you installing the OCLP to (internal or USB)?
 

Destroyer1976

New Tinkerer
Sep 8, 2025
10
0
1
Queensland, Australia
1)
I got my mac ROM cleaned by 'Macschrauber' and he sent me 2 copies. one with 'Enable-Gop' installed in the rom and the other without 'Enable-Gop'

2)
After installing open Core, OCLP told to use option key upon startup. What key should I press then?
Quote when finishing install to usb
"You will need to reboot and hold the Option key and select opencore/efi option"

3)
It hasn't been easy for me, not for me at least.

4)
I bought my AMD RX580 from 'macprofixer' on eBay. he said I could install 'Mojave' but it would allow me to install 'Sequoia'

quote from email
(Me)
"Was this graphics card flashed to show the boot screen on mac pro 5.1?"

(Macprofixer)
"Yes it was flashed to show boot screen, the card has dual bios, original pc and mac efi"

5)
After pressing 'option' I'm sitting waiting in the dark, until I turn it off

6)
I don't have any other graphics cards to test with. I can eventually sign into the mac with oclp installed. I only have one mac pro 2012 5.1. I installed oclp to a USB drive.

Does this help?? Please be kind, I'm very new to this, very much a novice. It's very frustrating
 

phunguss

Active Tinkerer
Dec 24, 2023
441
375
63
Stillwater, MN
Let's back up a step. You have Mojave installed. You can boot the computer with black screen and log in, then you get the desktop.

The first step would be to install OCLP 2.4.1 onto the existing hard drive (don't even connect your USB Sequoia installer yet). OCLP should identify your existing hardware on it's own and choose the most appropriate modifications to apply. Don't change anything and leave it at the defaults. Mojave does NOT require root patches, so that button should be grayed out. Install it to the internal hard drive and reboot. You should get a boot picker screen.