Windows 10 EFI on MacPro 4,1 -> 5,1

vrl2

macrumors newbie
Original poster
Jul 27, 2018
2
0
Hi,

I'm attempting an EFI install of Windows 10 on a 2009 (4,1) Mac Pro firmware upgraded to 5,1. I'm running High Sierra, and installing Windows 10 on a second partition on the same disk. I have no problem installing Windows 10 via bootcamp (which defaults to legacy mode). In this case, the Windows Bootcamp Drivers (v. 5261) install perfectly and Windows boots normally (i.e., when holding ALT during bootup, I can select a partition labeled "Windows." I am also able to boot directly back and forth b/w Windows and Mac using Bootcamp Control Panel in Windows 10 / "Startup Disk" in High Sierra).

The problem is that I cannot seem to properly install Windows 10 in EFI mode. In order to install using the EFI option on the Win10 Install DVD (or a USB installation), I first have to create a partition (using Bootcamp Assistant or Disk Utility) and then reset my MBR to "Protected" wth Gdisk. I can then perform an EFI installation of Windows 10, but when I run BootCamp's drivers (I've tried BootCamp 5.1 v. 5261, as well as 6.1 and 4.0), Windows crashes with a black screen and then turns off.

Additionally, when I perform an EFI installation, I cannot boot into Windows XP from High Sierra using "Startup Disk." Although "Windows" appears in the last of startup options, if I reboot from "Startup Disk" I get a black screen with a flashing DOS cursor. With a legacy installation, I don't experience this issue.

I believe that Windows 10 EFI is not properly detecting my video card (an Apple NVIDIA GeForce GT 120). In Legacy mode, the bootcamp drivers properly register it as a GT 120, but in EFI mode, Windows recognizes it as a GeForce 9500 GT. With an EFI install, the only way I can boot fully is to first disable the Display Adapter in Safe Mode. Any attempt to install a video card driver (with Bootcamp or using NVIDIA's drivers) causes windows to crash and go into a boot loop until I disable the video card. Normal workarounds (like running BootCamp.msi from an elevated command prompt, or editing the launch conditions for BootCamp.msi using orca) let me complete installing Bootcamp in EFI, but I still have to disable the Display Adapter in safe mode, and I still cannot boot into Win10 from OS X (using "startup disk").

I've tried editing Bootcamp's Info.plist (to enable Windows 10, USB, and edit the 'PreUEFI' section) but this doesn't make a difference. I've also tried using WinClone to convert a (working) Legacy Mode windows installation into an EFI installation and I get the exact same errors (a bootloop until I disable the display adapter in safe mode).

I would keep the Legacy Mode installation and forget about the EFI installation - but my goal is to create additional partitions so that I can eventually triple-boot (which I cannot do with a Legacy Mode installation, which limits me to 4 partitions per disk). I would also like to avoid using alternative boot managers (like reFInd) and stick with the Apple Boot Manager instead.

If anyone had any insights, I'd really appreciate any help in getting my EFI installation to work (or, alternatively, adding partitions to a legacy installation).

Thanks!
 
Last edited:

vrl2

macrumors newbie
Original poster
Jul 27, 2018
2
0
Hi,

I'm attempting an EFI install of Windows 10 on a 2009 (4,1) Mac Pro firmware upgraded to 5,1. I'm running High Sierra, and installing Windows 10 on a second partition on the same disk. I have no problem installing Windows 10 via bootcamp (which defaults to legacy mode). In this case, the Windows Bootcamp Drivers (v. 5261) install perfectly and Windows boots normally (i.e., when holding ALT during bootup, I can select a partition labeled "Windows." I am also able to boot directly back and forth b/w Windows and Mac using Bootcamp Control Panel in Windows 10 / "Startup Disk" in High Sierra).

The problem is that I cannot seem to properly install Windows 10 in EFI mode. In order to install using the EFI option on the Win10 Install DVD (or a USB installation), I first have to create a partition (using Bootcamp Assistant or Disk Utility) and then reset my MBR to "Protected" wth Gdisk. I can then perform an EFI installation of Windows 10, but when I run BootCamp's drivers (I've tried BootCamp 5.1 v. 5261, as well as 6.1 and 4.0), Windows crashes with a black screen and then turns off.

Additionally, when I perform an EFI installation, I cannot boot into Windows XP from High Sierra using "Startup Disk." Although "Windows" appears in the last of startup options, if I reboot from "Startup Disk" I get a black screen with a flashing DOS cursor. With a legacy installation, I don't experience this issue.

I believe that Windows 10 EFI is not properly detecting my video card (an Apple NVIDIA GeForce GT 120). In Legacy mode, the bootcamp drivers properly register it as a GT 120, but in EFI mode, Windows recognizes it as a GeForce 9500 GT. With an EFI install, the only way I can boot fully is to first disable the Display Adapter in Safe Mode. Any attempt to install a video card driver (with Bootcamp or using NVIDIA's drivers) causes windows to crash and go into a boot loop until I disable the video card. Normal workarounds (like running BootCamp.msi from an elevated command prompt, or editing the launch conditions for BootCamp.msi using orca) let me complete installing Bootcamp in EFI, but I still have to disable the Display Adapter in safe mode, and I still cannot boot into Win10 from OS X (using "startup disk").

I've tried editing Bootcamp's Info.plist (to enable Windows 10, USB, and edit the 'PreUEFI' section) but this doesn't make a difference. I've also tried using WinClone to convert a (working) Legacy Mode windows installation into an EFI installation and I get the exact same errors (a bootloop until I disable the display adapter in safe mode).

I would keep the Legacy Mode installation and forget about the EFI installation - but my goal is to create additional partitions so that I can eventually triple-boot (which I cannot do with a Legacy Mode installation, which limits me to 4 partitions per disk). I would also like to avoid using alternative boot managers (like reFInd) and stick with the Apple Boot Manager instead.

If anyone had any insights, I'd really appreciate any help in getting my EFI installation to work (or, alternatively, adding partitions to a legacy installation).

Thanks!
 

Project Alice

macrumors 6502a
Jul 13, 2008
722
394
Post Falls, ID
I have a full EFI install of Windows 10 on a mid 2009 MacBook, with the 9400m. I had the same problem at first. It would work fine until it installed video drivers. After days of googling, I came across a fix for the macbook. The windows nvidia drivers expect there to be a VGA port for the GPU, when there isn't. I found an EFI script which tells windows that there is a VGA port; loaded using rEFInd makes it work perfectly.

I don't know if this is the same issue on a 4,1 5,1 MP. But its somewhere to start.

I can tell you that you're NOT out of luck. I've seen a million different forums where people have said windows 10 works fine in EFI mode on 09 and up Mac Pros. Most people don't use the original GPUs in those, either. So that could be it.
 

1151105

macrumors member
Oct 23, 2018
41
4
th3 n0rth
i managed to install win10 through High Sierra bootcamp [89 firmware].
i modded the plist file and used the 1803 installer and created a partition on the OSx drive [~50gb]. no usb, no cd.

osx rebooted to the windows installer where i deleted a spare drive and installed win10 there. i left the 50gb partition on the mac drive because i was about to install mojave and upgrade to 140 [which i have now down but have not been able to install windows in mojave this way].