MP 1,1-5,1 cMP can no longer boot Mojave with OpenCore?

[Mike Richardson]

I am getting an error that says "This version of Mac OS X is not supported on this platform! Reason:Mac-27AD2F918AE68F61".

I have an NVMe drive that is partitioned with both Monterey and Mojave. It used to boot Mojave fine a long time ago, when I first installed OC?

If I google "27AD2F918AE68F61" it seems to be the identifier having to do with a MacPro7,1 and this is what I see in my EFI/OC/config.plist file.

I'm not sure why this identifier is being used (I seem to recall a guide online that recommended pretending to m. I think I was trying to get accelerated video to work with my RX580 (which it does right now).

I don't want to try another identifier in fear of bricking the boot unless someone else can report that such identifier works for them.

I also don't want to break acceleration in Monterey.

 

[Mike Richardson]

Adding -no_compat_check to boot-args did not help at all.

 

[Macschrauber]

Adding -no_compat_check to boot-args did not help at all.

you need to do that in the OC config.plist

 

[sfalatko]

you need to do that in the OC config.plist

Indeed - you are spoofing a MacPro 7,1 in your config.plist and Mojave is not supported on the 7,1...

 

[h9826790]

Change the board ID to Mac-7BA5B2D9E42DDD94.

Both Mac-7BA5B2D9E42DDD94 and Mac-27AD2F918AE68F61 can be used to fully activate HWAccel for your RX580.

But Mac-27AD2F918AE68F61 doesn't support Mojave.

The downside to use Mac-7BA5B2D9E42DDD94 is that iMac Pro only has one build in monitor. Your graphic card's framebuffer may be affected. Therefore, you should also add agdpmod=pikera into the boot argument to alleviate this issue.

But if your monitor stay black after switch to Mac-7BA5B2D9E42DDD94, try other ports first. Some of the ports usually still working.

This is an example of how to change from Mac-7BA5B2D9E42DDD94 to Mac-27AD2F918AE68F61. What you need to do is the other way around (and add agdpmod=pikera into the boot argument).

 

[Mike Richardson]

Looks like I am using Open Core Legacy Patcher (it was also out of date so I went ahead and updated it).

Selected iMacPro1,1 to spoof as and rebooting to Mojave now.

Edit: Now in Mojave. The other day I just wanted to play a game, this time I needed to format a spinning drive with HFS Extended Encrypted and they took all those options away, even though it mounts just fine.

Thanks for the info about the dual displays also. I'm only using 1 right now but I have had a dual setup before.

 

[h9826790]

Edit: Now in Mojave. The other day I just wanted to play a game, this time I needed to format a spinning drive with HFS Extended Encrypted and they took all those options away, even though it mounts just fine.

Format the drive, not the partition / container.

You cannot format a partition inside an APFS container to HFS+.

But you can format the drive itself to HFS+.

 

[batmandela]

Looks like I am using Open Core Legacy Patcher (it was also out of date so I went ahead and updated it).

Selected iMacPro1,1 to spoof as and rebooting to Mojave now.

Edit: Now in Mojave. The other day I just wanted to play a game, this time I needed to format a spinning drive with HFS Extended Encrypted and they took all those options away, even though it mounts just fine.

Thanks for the info about the dual displays also. I'm only using 1 right now but I have had a dual setup before.

Hello Mike - did you ever manage to solve this? I have a similar issue - trying to boot into my Mojave system gives me the exact same error. I also have Monterey on another drive, working really well on my MacPro 5,1 with OCLP and an RX580. I believe my problem is also the spoofing that was injected into the graphic card bootrom with the latest version of OCLP (which I selected when creating my EFI so that the bootloader picker thingy startup disk chooser would show up on startup... *terminology may not be correct...)

I would love to have my old Mojave system working, as I have a bunch of Logic songs on there, and sometimes the audio plugin info doesn't get transferred correctly to the Monterey system and the later version of Logic.

But I use multiple monitors (3 with my original RX570, hopefully all 4 with the RX580) and don't want to lose those...

Please let me know if you managed to fix this without breaking anything else in the process! Thanks so much.

 

[tsialex]

Hello Mike - did you ever manage to solve this? I have a similar issue - trying to boot into my Mojave system gives me the exact same error. I also have Monterey on another drive, working really well on my MacPro 5,1 with OCLP and an RX580. I believe my problem is also the spoofing that was injected into the graphic card bootrom with the latest version of OCLP (which I selected when creating my EFI so that the bootloader picker thingy startup disk chooser would show up on startup... *terminology may not be correct...)

I would love to have my old Mojave system working, as I have a bunch of Logic songs on there, and sometimes the audio plugin info doesn't get transferred correctly to the Monterey system and the later version of Logic.

But I use multiple monitors (3 with my original RX570, hopefully all 4 with the RX580) and don't want to lose those...

Please let me know if you managed to fix this without breaking anything else in the process! Thanks so much.

You are asking something that is clearly explained in this thread, read post #5:

https://forums.macrumors.com/threads/cmp-can-no-longer-boot-mojave-with-opencore.2398965/post-32392406

 

[batmandela]

Looks like I am using Open Core Legacy Patcher (it was also out of date so I went ahead and updated it).

Selected iMacPro1,1 to spoof as and rebooting to Mojave now.

Edit: Now in Mojave. The other day I just wanted to play a game, this time I needed to format a spinning drive with HFS Extended Encrypted and they took all those options away, even though it mounts just fine.

Thanks for the info about the dual displays also. I'm only using 1 right now but I have had a dual setup before.

Hello Mike - did you ever manage to solve this? I have a similar issue - trying to boot into my Mojave system gives me the exact same error. I also have Monterey on another drive, working really well on my MacPro 5,1 with OCLP and an RX580. I believe my problem is also the spoofing that was injected into the graphic card bootrom with the latest version of OCLP (which I selected when creating my EFI so that the bootloader picker thingy startup disk chooser would show up on startup... *terminology may not be correct...)

I would love to have my old Mojave system working, as I have a bunch of Logic songs on there, and sometimes the audio plugin info doesn't get transferred correctly to the Monterey system and the later version of Logic.

But I use multiple monitors (3 with my original RX570, hopefully all 4 with the RX580) and don't want to lose those...

Please let me know if you managed to fix this without breaking anything else in the process! Thanks so much.

You are asking something that is clearly explained in this thread, read post #5:

https://forums.macrumors.com/threads/cmp-can-no-longer-boot-mojave-with-opencore.2398965/post-32392406

Hello Alex - I read that post. It's the section in Part 5 that says:

"Some of the ports usually still working."

...that grabbed my attention. I have a 3/4 multi-monitor setup in my studio. I can't afford for "some of them" to work.

I know it's probably super-annoying for you that the same question gets answered again and again, but everyone's individual setup is slightly different, and the devil is in the details... That ONE thing that isn't exactly the same in a use-case scenario is often the one that trips me up. Hence I was asking Mike if he had tried this and triggered any unintended consequences.

I have read so many different incredible and informative posts that cover one aspect of the question I'm trying to answer (a lot of them yours!) - but there are also loose threads, questions left hanging as people solve their problems and move on, without updating their original post with the solution...

Apologies if it seems like I am coming here for a quick fix. Far from it... I must have watched 20 videos and read at least 100 threads trying to figure out the safest way to solve this.`It's hard to separate the wheat from the chaff. Your input is invaluable.

Thanks again.

 

[tsialex]

Hello Alex - I read that post. It's the section in Part 5 that says:



...that grabbed my attention. I have a 3/4 multi-monitor setup in my studio. I can't afford for "some of them" to work.

Simple and easy solution, boot your Mojave install directly from the Apple native BootPicker, completely bypassing OC and avoiding spoofing with the iMacPro1,1 board_id.

If you don't have a MacEFI flashed GPU, my BootROM reconstruction service includes EnableGop support, so, you'll have pre-boot configuration with any modern UEFI PC GPU that still have the factory firmware and is not modified for mining crypto (as almost all 2nd hand sourced GPUs are). I'll send a PM with instructions/files required/service fee/turnaround time.

 

[batmandela]

Thanks Alex.

Am I experiencing this issue because I custom selected the “inject GOP AMD option in the OCLP settings when creating my EFI?

Am I correct in the assumption that booting up with my original RX570 graphics card will solve the issue…

Will your BootROM construction service mean that I will be able to start up with the BootPicker and boot into any OS with full multi-monitor support on the RX580?

Thanks for your help, as always.

 

[tsialex]

Thanks Alex.

Am I experiencing this issue because I custom selected the “inject GOP AMD option in the OCLP settings when creating my EFI?

No, from what you wrote you still doesn't understand the real issue.

2019 Mac Pro board-id is being spoofed by OpenCore so a MacPro5,1 can boot unsupported macOS releases. Since 2019 Mac Pro can only boot Catalina 10.15.2 forward, if the OC config of the MacPro5,1 is spoofing a 2019 Mac Pro, you won't boot Mojave and anything earlier than 10.15.2.

iMacPro1,1 support starts with 10.13.2, so Mojave is fully supported, but with the adverse effect that you won't have multi-display support.

Am I correct in the assumption that booting up with my original RX570 graphics card will solve the issue…

Like I wrote in my previous post, if your GPU is MacEFI flashed you can bypass OpenCore and boot Mojave natively.

Will your BootROM construction service mean that I will be able to start up with the BootPicker and boot into any OS with full multi-monitor support on the RX580?

Thanks for your help, as always.

Correct, since you will boot natively and will be bypassing OpenCore, you can boot any macOS releases that have drivers for your GPU. So, you can boot Sierra/HighSierra/Mojave natively with your RX 570/580.

For newer unsupported macOS releases, you still need OpenCore.

 

[batmandela]

Like I wrote in my previous post, if your GPU is MacEFI flashed you can bypass OpenCore…

I bought an unmodified RX580 Pulse Sapphire 8Gb.

I used the late Dec 2024 version of OCLP to create the EFi. The only custom graphic-card related setting I altered was the one where I checked “Inject GOP on AMD card”.

Does this mean my card has only been MacEfI flashed? and that I am therefore able to bypass Open Core without having you build a custom BootROM?

I am not sure how to disable Open Core, or how complicated it is. Thanks again.

 

[batmandela]

Just for clarity’s sake: I am fully aware of the spoofing issue and its limitations.

Where my confusion arises is that I did an install of OCLP Monterey when I was still using my RX570, and was able to switch freely between the Mojave and Monterey systems.

When I swapped out my graphics card and installed the new WiFi and Bluetooth I rebuilt an OCLP EFI and enabled that GOP injection option.

Hence my confusion as to where the issue actually originated.

Apologies if my terminology is faulty.

 

[tsialex]

Does this mean my card has only been MacEfI flashed?

No. This is just an OpenCore config setting and have nothing to do with MacEFi flashing.

and that I am therefore able to bypass Open Core without having you build a custom BootROM?

No.

I am not sure how to disable Open Core, or how complicated it is. Thanks again.

You don't need to disable anything, just bypass.

After you flashed the reconstructed BootROM image to the Mac Pro, you power on the MacPro5,1, press ALT, wait for the Apple native BootPicker, select Mojave with the BootPicker and then natively boot it without OpenCore.

If you do no press ALT, OpenCore will be loaded and you can run unsupported macOS releases.

 

[tsialex]

Where my confusion arises is that I did an install of OCLP Monterey when I was still using my RX570, and was able to switch freely between the Mojave and Monterey systems.

When I swapped out my graphics card and installed the new WiFi and Bluetooth I rebuilt an OCLP EFI and enabled that GOP injection option.

Hence my confusion as to where the issue actually originated.

Apologies if my terminology is faulty.

Maybe your RX 570 is MacEFI flashed, check it, or you had iMacPro1,1 spoofing enabled instead of MacPro7,1. Apple native BootPicker is a grey screen with the drives icons, while OC one is black.

Apple Native BootPicker:

OpenCore BootPicker:

Both images are from OCLP Guide:

Booting OpenCore and macOS | OpenCore Legacy Patcher

 

[batmandela]

Thanks. I am familiar with the different BootPickers.

I just tried starting up holding the Alt key down to bypass OpenCore and have been met with a black screen. Is this option only after you have modified the BootROM?

¯\_(ツ)_/¯

I don’t believe my Rx570 was flashed, although I did buy it as a custom build from a UK company a few years ago and they might have flashed it.

This guy has some great videos. I’ll maybe watch a few more and educate myself on this new aspect of Open Core.

Peace!

 

[tsialex]

I just tried starting up holding the Alt key down to bypass OpenCore and have been met with a black screen. Is this option only after you have modified the BootROM?

With a PC GPU installed in a MacPro5,1, you’ll only have pre-boot configuration support/the Apple native BootPicker if:

• The PC GPU is firmware flashed with a MacEFI or
• The Mac Pro BootROM is modified with EnableGOP injection and the GPU still have the factory installed GPU firmware unmodified, not the case with 2nd hand GPUs bought from crypto mining operations.

There are other much more complex ways to boot Mojave without iMacPro1,1 multi-display restrictions, like multi config.plist, but then is required extreme advanced hackery that will be needed to be re-done each time you upgrade OC.

So, you need a MacEFI flashed GPU or modified MacPro5,1 BootROM.

 

[tsialex]

Btw, black screen while pressing ALT at power-on is a confirmation that the GPU is not MacEFI flashed.

 

[batmandela]

Thanks for all that info Alex.

I did some research on the SMBIOS spoofing and realized that I can just spoof as MacPro 6,1 for now as it supports 10.9 to Monterey.

If I decide to go beyond Monterey I’ll create a different spoof model and figure out the monitor/hardware issues.

Regarding the black screen - eventually my Mac rebooted into Mojave and then it didn’t want to move out of there so I had to remove the drive to start up with OpenCore.

And now my Bluetooth shows up as NULL - even though the Magic Mouse is working.

I know o fixed that before but can’t remember how. So many little battles won and lost along the way.

I’ll have to figure out what I did before to restore it. I don’t believe it was with Configurator…

Thanks again.

 

[tsialex]

I did some research on the SMBIOS spoofing and realized that I can just spoof as MacPro 6,1 for now as it supports 10.9 to Monterey.

Flawed idea, spoofing a MacPro6,1 will have the same issues with multiple displays as iMacPro1,1. No one uses MacPro6,1 as a board-id to run unsupported macOS releases, to many adverse effects.

You are forgetting that the MacPro6,1 have dual GPUs with just one HDMI output and the rest is TB - won't match with your RX 570/580 personality and you will have black screens with multiple displays exactly like you have when spoofing an iMacPro1,1.

Also, with MacPro6,1, you can't enable AMD hardware acceleration and a lot of other things that iMacPro1,1 and MacPro7,1 support.

 

[batmandela]

😬

I’ll have a look at all those files you need for the custom BootROM build. Seems like that’s the safest way.

If I could just figure out how to fix the BT issue. It was working for perfectly before I booted into Mojave. 😩

 

[tsialex]

If I could just figure out how to fix the BT issue. It was working for perfectly before I booted into Mojave. 😩

When you boot back to Mojave, after running Monterey, you need to do a multiple continous NVRAM reset.

Apple with Catalina forward implemented a different sintaxe for the BT related NVRAM variables that is incompatible with Mojave.

 

[batmandela]

Thanks Alex. Sorry for late reply. Been ill. I had been doing deep resets, but not since this issue.

Redoing deep NVRAM reset helped.