MP 1,1-5,1 Dual booting OCLP with Monterey and Windows 10 (not bootcamp)

[AndreiC1011]

Hello everyone,

I know this is a very hot subject here on this forum, but I cannot seem to find the answer I need on any of the other posts.

So I have a Mac Pro 5.1 which until yesterday had the stock Radeon 5770 GPU. I was running without a problem Opencore Monterey and a Windows 10 bootcamp installation which I could easily select via the bootloader.

I decided to upgrade to a Sapphire Nitro + RX580 8 gb but this is when my problems started: for some reason the OCLP installation got corrupted upon swapping the GPU and I could not properly re-patch and I lost USB 1 and Bluetooth/WIFI functionality (which I read is an known issue). I read that this could happen and a clean installation would solve this.

So I decided to install a “clean” OCLP Monterey on a blank SSD. I found a good tutorial online to install without bootloader and intend to follow it.

My question: is there any way to install Windows 10 using the RX 580 and to dual boot it via the OCLP EFI? And how do I swap between the 2 OS without a bootloader?

Thank you!

 

[Macschrauber]

You can add a bootscreen by adding a firmware module to the Mac Pro.

Here is a very detailed video:

 

[AndreiC1011]

Thank you very much!

I saw this video, but I am sort of a newbie on Mac (I got this 5.1 only 2 weeks ago) and to be honest I am quite afraid to mess with the bootrom and end up bricking the Mac.

But I am guessing there is no workaround in dual booting with the OCLP installed (I know that without it you can select the start up disk and it is somewhat functional).

Oh well, probably I will just have to take the risk and add the firmware module or buy a GT 120 and use it as a secondary GPU only to see the bootloader.

Thank you again! 🙏

 

[AndreiC1011]

You can add a bootscreen by adding a firmware module to the Mac Pro.

Here is a very detailed video:

Thank you very much!

I saw this video, but I am sort of a newbie on Mac (I got this 5.1 only 2 weeks ago) and to be honest I am quite afraid to mess with the bootrom and end up bricking the Mac.

But I am guessing there is no workaround in dual booting with the OCLP installed (I know that without it you can select the start up disk and it is somewhat functional).

Oh well, probably I will just have to take the risk and add the firmware module or buy a GT 120 and use it as a secondary GPU only to see the bootloader.

Thank you again! 🙏

 

[Macschrauber]

combining a 2nd GPU does not work with modern OS on the Mac.

You can chainload a 2nd bootloader what can load csr Windows. Search for chainload.

You can use Dayo's RefindPlus to chainload OpenCore.

But those 2 paths arent exactly easy, too.

 

[AndreiC1011]

combining a 2nd GPU does not work with modern OS on the Mac.

You can chainload a 2nd bootloader what can load csr Windows. Search for chainload.

You can use Dayo's RefindPlus to chainload OpenCore.

But those 2 paths arent exactly easy, too.

Understood.

Then I will have to do my homework and prepare to do one of these solutions.

Or to just install Windows using my old GPU and forget about OCLP altogether.

In any case if I will try to add the firmware module I will probably kindly ask you to help me if I need a rebuilt bootrom.

Again, thank you for your quick and informative replies!

 

[AndreiC1011]

Hello again,

With the kind help of Macschrauber (who made a clean bootrom for me) I managed to install EnableGOP on the cMP.

I encountered some problems because it seems one of the bioses on the card was modified by the previous owner.

Luckily, this card had a bios switch and the second (silent) bios was unaltered. I can now see a bootloader!

Furthermore, the bluetooth which was not working before seems to be working now.

I did encounter some problems when using dual screens since it seems HDMI is causing some issues. In my case, when using 2 screens I cannot see the actual boot loader only the OCLP boot loader and also the HDMI display sometimes fails to turn on. But for these I will ask for help on some other threads.

Thanks again!