Installing Windows on a Mac Pro 5.1 running opencore.

[Svenv1]

Hi, I'm running a Mac Pro 5.1 (original 2010) with Big Sur on open core with the following specs:

CPU: 2 x 2,9 GHz 6-Core Intel Xeon
Memory: 48 GB 1333 MHz DDR3
GPU: Radeon RX 580 8 GB

SSD 1: 500GB SSD running Big Sur/opencore
SSD 2: 256GB SSD currently containing Catalina, will be the Windows disk
HDD 1: 80GB HD used for data only.

I want to install Windows next to Big Sur on my 256GB SSD SSD2) and every now and then boot into it, preferably via open core.

I found some various guides/posts that concerned me a bit on the approach. One stated that you should not use a USB drive for installation as it might temper with the firmware an potentsially corrupt it.

Classic Mac Pro (5,1): installing Windows 10, switching between macOS Mojave & Windows without boot screen - CrystalIDEA Blog

crystalidea.com

I've also found tutorials that explicitly say to do use an usb drive (though potentially a dvd-rom can be used as replacement medium).

I have a few questions:

- Is any of these procedures up to date?
- If I corrupt the firmware, will I be able to recover it?
- Can I use the YouTube procedure safely using a DVD-rom (better safe than sorry).
- Can I use the RX 580 while installing or do I need to fit in a boot screen gpu for the installation?
- Does anyone have more recommendations/advice suggestions for this?

 

[Omnath]

I'm in a similar position and would love to know if this method works without corrupting my boot rom.

I use A Mac Pro 4.1 flashed to 5.1 and could install Windows 10 on a SSD in my other computer but I am scared it might brick my cMP booting Windows without making the right changes before :/

 

[DaveFromCampbelltown]

I have installed Win10 on an external USB 3 SSD using Hasleo's WinToUSB, but that is with a 2015 iMac. The linked article says there may be problems with the firmware if you use it on a MacPro, so I can't comment if it would work on your computer.

I do know that upgrading to Catalina, and then later to Big Sur did make changes to my firmware, which has made selecting boot volume by holding down the Option key at startup somewhat problematical.

 

[thielsa]

I have Big Sur with OpenCore on my main drive. I followed the OpenCore with MacPro instructions to add Windows 10 onto a separate drive. If you follow the instructions it does work. I now have windows 10 showing up on the boot screen of open core and can either go to Big Sur or Windows.

 

[Omnath]

I tried the method in the video as well and the only thing I was doing differently was that I created the USB installmedia with a real PC. I cant find the stick to install Windows though.

Then I installed Windows on a SSD in my PC with legacy mode and put it into my Mac Pro. It shows a Windows installation in the system preferences and I tried to start it from there but it tells me "SDErrorDomain-Fehler 104". In Open Core I cant find the Windows drive and therefore I cant boot it although there is a perfectly fine Windows installation :/

Can someone help me with that?