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MP 1,1-5,1 Can't boot into Mojave from Windows 10

B

BerndL

macrumors newbie
Original poster
Sep 12, 2022
8
1
Hi there,
I have successfully installed Windows 10 onto a separate SSD in Mac Pro 2012.
Details as follows:
Mac OS: Mojave, version 10.14.6 installed on HDD - GPT - Mac OS Extended Journaled - Drive Bay 3
Windows OS: Windows 10 Legacy version 20H2 installed on SSD (SATA 860 EVO) - MBR - NTFS - Drive Bay 4
BootRom: 144.0.0.0.0
GPU = Radeon RX570, as such I have no Boot Screen
Procedure to install:
forums.macrumors.com

How to: Boot Camp without a Boot Screen

[Update 29 Feb 2020: Members reported that this procedure will install Boot Camp 6.1.9 now, which apparently only allow users boot to the latest macOS drive. For those who has multiple macOS drive. This method doesn't work anymore. Also, latest Windows 10 (1909) seems also not allow Bootcamp 5...
forums.macrumors.com forums.macrumors.com

created a DVD with version 1803
used Brigadier to get the Apple drivers and Bootcamp control panel

upgraded Windows to version 20H2
upgraded AMD drivers
used Brigadier again for Apple drivers and Bootcamp control panel

To play safe, I installed Legacy option for Windows and don't want to use Open Core.

While I can access and change the startup Drive in the Bootcamp Control Panel, my System always starts in Windows, even if I select Mac OS.

What am I doing wrong? Does the Mac OS and the Windows have to be installed on the same drive for Bootcamp to work?

Any advice very much appreciated.

Cheers Bernd
 
BerndL said:
Hi there,
I have successfully installed Windows 10 onto a separate SSD in Mac Pro 2012.
Details as follows:
Mac OS: Mojave, version 10.14.6 installed on HDD - GPT - Mac OS Extended Journaled - Drive Bay 3
Windows OS: Windows 10 Legacy version 20H2 installed on SSD (SATA 860 EVO) - MBR - NTFS - Drive Bay 4
BootRom: 144.0.0.0.0
GPU = Radeon RX570, as such I have no Boot Screen
Procedure to install:
forums.macrumors.com

How to: Boot Camp without a Boot Screen

[Update 29 Feb 2020: Members reported that this procedure will install Boot Camp 6.1.9 now, which apparently only allow users boot to the latest macOS drive. For those who has multiple macOS drive. This method doesn't work anymore. Also, latest Windows 10 (1909) seems also not allow Bootcamp 5...
forums.macrumors.com forums.macrumors.com

created a DVD with version 1803
used Brigadier to get the Apple drivers and Bootcamp control panel

upgraded Windows to version 20H2
upgraded AMD drivers
used Brigadier again for Apple drivers and Bootcamp control panel

To play safe, I installed Legacy option for Windows and don't want to use Open Core.

While I can access and change the startup Drive in the Bootcamp Control Panel, my System always starts in Windows, even if I select Mac OS.

What am I doing wrong? Does the Mac OS and the Windows have to be installed on the same drive for Bootcamp to work?

Any advice very much appreciated.

Cheers Bernd
Click to expand...

Windows boot coups can be solved with a continuous NVRAM reset, unless you already have a corrupted NVRAM.

Start by physically removing the Windows disk from your Mac Pro and then try to reset at least four times consecutively, from a wired keyboard, only let CMD-Option-P-R keys go after the 5th chime.

After reset is done, you can install back your Windows disk and check if it's working as expected.

FreakinEurekan said:
Yes.
Click to expand...
Definitively not, this is a Mac Pro, not a MacBook.
 
Thanks tsialex,
There was some erratic behavior on my machine that is gone after the reset of the NVRAM. Thank you for that :)
Is is a good idea to reset NVRAM from time to time (even if there are no issues)?

Unfortunately, Windows is still not able to initiate a boot into Mac OS. The system can see the Mac Drive, I can select it, but it will stubbornly stick to Windows.

AppleControlPanel.exe is Version 6.1.7800.4
AppleOSSMgr.exe is Version 6.1.7600.0
 
pull the windows drive and force it to boot off macos. then select mac in the osx control panel as your boot drive.
 
Thanks macguru9999,
I am working predominantly with Windows. But from time to time, I want to switch back to Mac OS. Pulling the windows drive every time I want to switch back is no fun. And since I read that I should be able to switch after restart using Apple Control Panel from the Bootcamp utility in Windows to select my startup drive, it is becoming frustrating.
 
You can install a boot manager such as RefindPlus to allow you select between Mac OS and Windows each time you boot. You can configure it to always boot one option unless you intervene or to wait for you to make a selection each time. RefindPlus is derived from rEFInd which can also be used, but rEFInd does not natively support RX 570 on cMP.

You say you don't want to use OpenCore so you can follow instructions on installing RefindPlus on its GitHub page but it might however be easier to use MyBootMgr, (linked in my signature below).

This will set both RefindPlus and OpenCore up. You can keep and try OpenCore in this case and maybe you will see the virtues after this; but if you do indeed not want it at all, just delete the OpenCore folders it creates as well as the entries for running it in the RefindPlus config. These will be near the bottom of the RefindPlus config file.

I know you already have Windows but I find it better to have it installed Bare Metal (without BootCamp) as there are some irritations with BootCamp. Basically, the whole BootCamp setup is a nasty hack to make Windows work for Apple by setting up "HybridMBR" disks.

It might not be as bad with Mojave, but there are sometimes issues such as Spotlight indexing BootCamp forever and chewing up CPU cycles. You can read about other potential HybridMBR issues here: rodsbooks.com/gdisk/hybrid.html.

Bare Metal Windows might not be an option for you since you are already up and running with BootCamp though and the HybridMBR stuff might not be relevant for you either.
 
Last edited:
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Thanks Dayo,
Very much appreciated, I may give it a thought.

But the questions remains: Is it possible to use the Bootcamp utility from Windows 10, i.e. select your startup disk if Windows is installed on its own drive instead of the hybrid MBR?

If so, what do I need to do to get it work?

I was under the impression that AppleControlPanel.exe is able to write into NVRAM. Or is it that AppleCotrolPanel.exe makes changes to the hybrid MBR partition and this in consequence will change the NVRAM? I am lost here.
 
Sorry, I don't use BootCamp myself. Perhaps someone else would be able to chime in on that
 
BootCamp Windows control panel/applet can boot macOS without any trouble, dedicated disk or not. If it's not working you have something wrong with your BootROM.

It's easy to confirm or disprove, remove the Windows drive, boot macOS, go to SysPref/StartUp disk and select your macOS disk, reboot. Check if you can boot macOS, shutdown. Install your Windows disk again, power up.

If your Mac Pro boots Windows directly, you have a corrupt BootROM and will need a reconstruction service. This is relatively common with people that installed UEFI Windows in the past without OpenCore Windows SecureBoot protection/block.
 
BerndL said:
Thanks Dayo,
Very much appreciated, I may give it a thought.

But the questions remains: Is it possible to use the Bootcamp utility from Windows 10, i.e. select your startup disk if Windows is installed on its own drive instead of the hybrid MBR?

If so, what do I need to do to get it work?

I was under the impression that AppleControlPanel.exe is able to write into NVRAM. Or is it that AppleCotrolPanel.exe makes changes to the hybrid MBR partition and this in consequence will change the NVRAM? I am lost here.
Click to expand...

I first used BootCamp (Windows 7) on a partition in an iMac, but when I bought my first cMP 1,1 (which I upgraded to a 2,1) I copied the partition to a separate SSD - it was a long time ago but I remember there being much pain to get it to work. Since then, I upgraded to Windows 8.1 and then copied the SSD to a newer and bigger SSD, and then upgraded again to Windows 10 (found out the Windows 8.1 key I bought was bogus but Microsoft sorted it for me) and then 11 (which requires some modifications to upgrade).

Throughout my time, up to and including Windows 8.1 and including when I upgraded to a cMP 4.1>5,1 (but before RefindPlus|OpenCore chainloader), I used the BootCamp Control Panel to boot to macOS from Windows, and used Paragon's NTFS for Mac to boot from macOS to Windows. But with the awesome advent of MyBootMgr's chainloader setup, I don't have to do that any more - I simply select either an instance of OpenCore to run Mojave, BigSur or Monterey, or I boot natively to Mojave or Windows 11. For my usage it works perfectly, and is incredibly well supported by @Dayo and other's tireless work.

I have never used the BootCamp Control Panel since moving to RefindPlus|OpenCore chainloader. Well actually I did one time, by mistake, and I then had convoluted issues booting back to RefindPlus: Remove my Windows SSD > boot natively into Mojave RecoveryHD > disable SIP > boot back into Mojave and used Terminal to firm bless my RefindPlus boot EFI ESP thingy).
 
BerndL said:
But the questions remains: Is it possible to use the Bootcamp utility from Windows 10, i.e. select your startup disk if Windows is installed on its own drive instead of the hybrid MBR?
Click to expand...

I don't know why others are saying this isn't possible, I did it all the time before I set up RefindPlus.

You're talking about right-clicking the Boot Camp Assistant icon in the task bar and choosing macOS as the startup disk from there, right?

I did it on the daily. Win 10 on an SSD in SATA bay 2, macOS 10.14 on an SSD in SATA bay 1.
 
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