Contribute
Register

Guide: Multibooting UEFI on Separate Drives

Joined
Nov 28, 2020
Messages
10
Motherboard
Gigabyte Z490 Vision D
CPU
i7 10700k
Graphics
5700XT
I am trying to put together a multiboot system (macOS Big Sur, Windows 10, and Ubuntu). I have all three on separate SSDs and only had one SSD connected at a time during the installations.

First, I installed macOS with OpenCore on the macOS SSD.
Second, I installed Windows 10 at UEFI-GPT on a second SSD. Everything works fine up to then.
Third, I installed Ubuntu on a third SSD. I made the installer with Rufus and selected UEFI and GPT. I had two options for the drive format in Rufus - FAT32 and NTFS. I chose FAT32, the default. When I booted into the Linux installer, I deleted all partitions visible partitions and installed Linux on the sole partition. It appeared to install fine.

When I boot up in OpenCore, I have macOS, Windows 10, Untitled, and Reset NVRAM. "Untitled" is my Linux drive. macOS and Windows boot and operate fine.
Hey diplomatt,

Hope to get some of your advice too. I am trying to do the same thing but without Ubuntu.
I've currently already got Windows 10 running perfectly fine on an NVME drive, and have a separate NVME drive that I'm reserving for Mac Big Surr. I've done the OpenCore OS installer on a USB drive waiting to be inserted.
I've got 3 other non-OS storage internal drives that have been formatted to ExFAT so I can access them through both operating systems.

Am I correct to unplug the Windows 10 NVME drive while I'm installing Mac OS? Once Mac OS is installed and running, would I be able to plug the Windows 10 NVME drive back in?
What is the process after that to ensure both operating systems work? What about being able to install updates on them as well?

Thanks in advance!
 

Going Bald

Moderator
Joined
Aug 14, 2010
Messages
23,234
Motherboard
GA-X58A-UD7-F7
CPU
W3670
Graphics
RX 580
Mac
  1. iMac
  2. MacBook Pro
  3. Mac mini
Classic Mac
  1. iMac
Mobile Phone
  1. Android
Hey diplomatt,

Hope to get some of your advice too. I am trying to do the same thing but without Ubuntu.
I've currently already got Windows 10 running perfectly fine on an NVME drive, and have a separate NVME drive that I'm reserving for Mac Big Surr. I've done the OpenCore OS installer on a USB drive waiting to be inserted.
I've got 3 other non-OS storage internal drives that have been formatted to ExFAT so I can access them through both operating systems.

Am I correct to unplug the Windows 10 NVME drive while I'm installing Mac OS? Once Mac OS is installed and running, would I be able to plug the Windows 10 NVME drive back in?
What is the process after that to ensure both operating systems work? What about being able to install updates on them as well?

Thanks in advance!
If Win10 is installed on the NVMe drive that was listed first in the default listing of boot drives in the UEFI/BIOS then it is not necessary to remove it before installing another OS on a separate NVMe drive. As long as you can tell the difference between the drives when you select a drive on which to install Mac OS so that you do not accidentally format the Win10 drive you should be all right. To ensure this you might want to boot Win10, open the explorer window, right click on the C:\ drive and select properties. Then enter a name for the drive in the box at the top of the properties window, click apply and OK then close the window. That way, in the Mac OS install screen asking you to select a drive the Win10 drive will show with the name you gave it. It will also show this name in the Disk Utility window, so if you are careful to select the non named drive to format for your Mac OS install then you will be OK.
 
Joined
Jun 28, 2016
Messages
72
Motherboard
Gigabyte GA-Z470 Vision G
CPU
I9-10850k
Graphics
RX 5700 XT
Mac
  1. MacBook Air
  2. MacBook Pro
Classic Mac
  1. Apple
  2. iMac
  3. LC
  4. Performa
  5. Power Mac
Mobile Phone
  1. iOS
Hey diplomatt,

Hope to get some of your advice too. I am trying to do the same thing but without Ubuntu.
I've currently already got Windows 10 running perfectly fine on an NVME drive, and have a separate NVME drive that I'm reserving for Mac Big Surr. I've done the OpenCore OS installer on a USB drive waiting to be inserted.
I've got 3 other non-OS storage internal drives that have been formatted to ExFAT so I can access them through both operating systems.

Am I correct to unplug the Windows 10 NVME drive while I'm installing Mac OS? Once Mac OS is installed and running, would I be able to plug the Windows 10 NVME drive back in?
What is the process after that to ensure both operating systems work? What about being able to install updates on them as well?

Thanks in advance!
Yes you should only install with the win drive disconnected. I used this guide back a while, it worked like a champ. https://www.tonymacx86.com/threads/guide-multibooting-uefi-on-separate-drives.198869/ although I didn't use linux as an option I imagine it will take you through the needed steps.
 
Joined
Nov 28, 2020
Messages
10
Motherboard
Gigabyte Z490 Vision D
CPU
i7 10700k
Graphics
5700XT
If Win10 is installed on the NVMe drive that was listed first in the default listing of boot drives in the UEFI/BIOS then it is not necessary to remove it before installing another OS on a separate NVMe drive. As long as you can tell the difference between the drives when you select a drive on which to install Mac OS so that you do not accidentally format the Win10 drive you should be all right. To ensure this you might want to boot Win10, open the explorer window, right click on the C:\ drive and select properties. Then enter a name for the drive in the box at the top of the properties window, click apply and OK then close the window. That way, in the Mac OS install screen asking you to select a drive the Win10 drive will show with the name you gave it. It will also show this name in the Disk Utility window, so if you are careful to select the non named drive to format for your Mac OS install then you will be OK.
Just renamed the drive to "Windows 10" as per your instructions.
I thought removing the Windows drive was so that Mac OS would not completely destroy it during the install?
I think I should be able to identify it pretty easily. The Windows NVME is 500GB and the NVME I reserved for Mac is 1TB.

Yes you should only install with the win drive disconnected. I used this guide back a while, it worked like a champ. https://www.tonymacx86.com/threads/guide-multibooting-uefi-on-separate-drives.198869/ although I didn't use linux as an option I imagine it will take you through the needed steps.
I read through the guide briefly but it seems to only mention about using Clover. Since I'm gonna have to use OC for Big Sur, would this guide still be applicable?
As per what Going Bald said, would it really be necessary to remove the Windows drive?

I bought a giant of a graphics card that sits over 2 of the NVME drives. Removing either one of them would also mean I would have to pull out my entire graphics card along with all the screws holding it in place. I'm not PC build savvy unfortunately and my first attempt barely got it working so I ended up taking it to a professional to fix up my cable management and refitting things.
I would be absolutely happy if there was a workaround of not having to unplug anything if possible!
 
Last edited:

Going Bald

Moderator
Joined
Aug 14, 2010
Messages
23,234
Motherboard
GA-X58A-UD7-F7
CPU
W3670
Graphics
RX 580
Mac
  1. iMac
  2. MacBook Pro
  3. Mac mini
Classic Mac
  1. iMac
Mobile Phone
  1. Android
@KrustyKrab
The problem with multiple drives connected and Win10 installation is the difficulty with identifying the default 1st drive in BBS boot order. This drive is the one on which you want to install Win10. The Win10 installer has a bad habit of putting the Win10 EFI on the default 1st drive even if it is not the drive selected for the Win10 installation because Microsucks wants Win10 to be the only OS in the system. It also may do the same with the drive selected to be first in BBS boot order depending on the motherboard and UEFI implementation. With a new build it is possible, if the drives are different OEM and/or different sizes, to boot to the UEFI and determine which drive is in the default 1st BBS boot order slot and re-arrange them if needed so that the Win10-to-be drive occupies that slot. Once installed in that slot there are no further problems (at least, I have not run across any) so long as you select this drive as first in BBS boot order manually before attempting to install Win10.
 
Last edited:
Joined
Nov 28, 2020
Messages
10
Motherboard
Gigabyte Z490 Vision D
CPU
i7 10700k
Graphics
5700XT
@Going Bald
Understood.
I actually got the Computer Tech guy to also update my Gigabyte BIOS, which gave it a whole new look (while also fixing some software issues we initially had).
I've just checked all the drives on the BIOS and it actually clearly lists the code name of each drive (eg. WDS100T3XHC). Simply googling that already gives me the answer as to which drive it is.
I'm going to attempt it now without removing any of the drives. Wish me luck!
 
Joined
Jan 14, 2021
Messages
4
Motherboard
Hewlett-Packard 212B
CPU
Intel Xeon E5-1650 v4
Graphics
nVidia Quadro M5000
Mac
  1. MacBook Pro
Mobile Phone
  1. iOS
MultiBooting Win10, OS X and Ubuntu on separate drives is as simple a procedure as installing all 3 on the same drive and booting them with Clover ( See http://www.tonymacx86.com/threads/guide-multibooting-uefi.197352/ ).
What you need:

3 HDDs or SSDs or some combination of the two.
Your installation USBs:

View attachment 205199

some time and patience.

For this guide, there is no need to give detailed installation instructions for OS X - this guide already exists.
Due to the way I install the boot files for Linux, I need to install OS X before installing Ubuntu.
You can install either OS X or Win10 first. I chose to do Win10 first.

The only special thing you need to do for Win10 is create the EFI partition as the first partition on the drive and format the drive GPT partition tables. This is easiest to do with the OS X Disk Utility, but it can be done from an elevated command window at the Win10 installer screen with diskpart. If you do not know how to do it with diskpart I suggest you do it with OS X Disk Utility. Note that CSM must be enabled for the installation process.

For Win10:
Connect a drive, insert OS X Install USB, boot the system and at the POST hit the Function hotkey that allows you to select a boot device. Select the OS X Install USB. At the installation screen, select Utilities->Disk Utility and format the drive single partition GUID/Mac OS Extended (Journaled). When done, exit Disk Utility. Quit the OS X installer.
Remove the OS X Install USB and insert the Win10 USB, boot the system and at the POST hit the Function hotkey that allows you to select a boot device.
Windows shows up as USB: Win10Installer (or whatever you named the USB) and as UEFI USB: Win10Installer.
Select the UEFI USB: Win10Installer and boot the system.
At the installation screen, select Custom Install. At the next screen select the OS X partition and delete it - do not delete the EFI partition. With the resulting free space hi-lited, install Windows to the space. The installer will create and format the partitions for you. When finished, update and install your 3rd party apps and security suite. Reboot to BIOS/UEFI and disable CSM. Save&exit, continue boot to desktop. Shut down, disconnect the drive.

For OS X:
Follow the guide at http://www.tonymacx86.com/threads/u...pitan-on-any-supported-intel-based-pc.172672/

I went ahead and upgraded to Sierra PB2 while I had a new installation of El Capitan just to make sure there were no surprises with Sierra.

For Linux:
You should have created your USB for UEFI installation. If you did not, you need to go back and do this. I found Rufus to work well for this.
Normally, I would disconnect the OS X drive before installing another OS. This time, since I want to install the Linux boot loader to the UEFI folder on the OS X drive, I will leave it connected.
So, with the system shut down, connect the next drive, insert the Linux Install USB, boot the system and at the POST hit the Function hotkey that allows you to select a boot device. Select the Linux Install USB and boot the system.

At the Grub screen boot the Live Linux default and then at the desktop double-click on the install icon.
Select your language (continue).
If your system has a fast network connection, click the burger dots to install updates during the installation process (continue). For Installation type, select "Something else" (continue). You should see something like this:
View attachment 205204

sda is obviously your OS X drive, sdb is your drive for Linux. Select it, click on new partition table. This will wipe the drive to free space. Create your swap, root, home, usr partitions as you normally would for Linux.
When done, make sure you select to put the boot loader files in the sda EFI partition:
View attachment 205205

Click on Install Now and go get a cup of coffee, take a bathroom break, do something else while Linux installs.
When the installation is complete, you will need to reboot. At the post, go ahead and hit the Function key to select the Linux drive to boot to finish the installation and create your user. Remove the install USB. Update if you did not select to update during install, download any apps you want, set the system up and get it working for you as you wish it to. When done, shutdown. Connect the Windows drive.

With all 3 OSs installed and all 3 drives connected boot to the UEFI BIOS and make the OS X drive first in BBS boot order.
When Clover screen shows you will only see icons for OS X and Windows. We will fix this with a config.plist edit.
Choose the OS X icon and boot to desktop. You will need to download Xcode or your favorite plist editor for this next step.
Mount the EFI partition and navigate to the config.plist. Open the config.plist in Xcode and add this entry:

View attachment 205207
Save the config.plist, quit Xcode and reboot. You will see this:
View attachment 205208

and this:
View attachment 205209

And that, my children is just how simple it is.

View attachment 205210

There is just one slight annoying problem I have not solved yet in Sierra: OS X complains "The disk you inserted was not readable by this computer" "Initialize Ignore Eject" when it boots, complaining about the Linux drive. Previous free 3rd party apps that worked for earlier versions of OS X do not seem to work at all in Sierra yet - maybe the authors will update their apps when the Gold Master is releaased. You can get used to the complaint and just click eject when you boot OS X or find/create another solution.
Hi, thanks for the info.

My system is already running Ubuntu 16.04 and Windows 10 and now I want to add OSX to the bunch. You stated that you had to installed Ubuntu after OSX. Is there a possibility to keep my installations and just add OSX to the existing installations or do I have to reinstall Ubuntu? Also, when I boot my current system, I actually get the Ubuntu OS loader, where Ubuntu is the default system and only if I scroll down to the Windows Boot manager it actually boots into Windows. Do you think it would be possible to add OSX to the Ubuntu Boot loader at all or do I have to start from scratch?
 

Going Bald

Moderator
Joined
Aug 14, 2010
Messages
23,234
Motherboard
GA-X58A-UD7-F7
CPU
W3670
Graphics
RX 580
Mac
  1. iMac
  2. MacBook Pro
  3. Mac mini
Classic Mac
  1. iMac
Mobile Phone
  1. Android
Hi, thanks for the info.

My system is already running Ubuntu 16.04 and Windows 10 and now I want to add OSX to the bunch. You stated that you had to installed Ubuntu after OSX. Is there a possibility to keep my installations and just add OSX to the existing installations or do I have to reinstall Ubuntu? Also, when I boot my current system, I actually get the Ubuntu OS loader, where Ubuntu is the default system and only if I scroll down to the Windows Boot manager it actually boots into Windows. Do you think it would be possible to add OSX to the Ubuntu Boot loader at all or do I have to start from scratch?
Separate or same drive?
If separate drive, install Mac OS on a new, blank drive. Install boot loader of choice (OC recommended if using Mojave, Catalina or Big Sur). Configure config.sys to scan for Windows and Linux. Boot to BIOS/UEFI and make the Mac drive first in BBS boot order. You should be able to select Mac OS, Win10 or Linux to boot them.
 
Joined
Jan 14, 2021
Messages
4
Motherboard
Hewlett-Packard 212B
CPU
Intel Xeon E5-1650 v4
Graphics
nVidia Quadro M5000
Mac
  1. MacBook Pro
Mobile Phone
  1. iOS
Separate or same drive?
If separate drive, install Mac OS on a new, blank drive. Install boot loader of choice (OC recommended if using Mojave, Catalina or Big Sur). Configure config.sys to scan for Windows and Linux. Boot to BIOS/UEFI and make the Mac drive first in BBS boot order. You should be able to select Mac OS, Win10 or Linux to boot them.
Thanks!

I have a separate SSD intended purely for OSX, so I follow your guide. Until I found out that my GPU is not supported by Mojave and newer OSs I was trying to configure OC, but since my GPU (nVidia M5000) won't ever be compatible with the new systems, I might as well use Clover and make life easier.

However, if I were to buy an AMD GPU that's compatible with all the recent OSs (Mojave, Catalina and Big Sur), could I install that in my workstation (next to my existing GPU) and hard-wire it to only be used with OSX? The goal would be to have two GPUs, but only use one at any given time, i.e. nVidia for Linux & Windows, and AMD for MacOS.
 

Going Bald

Moderator
Joined
Aug 14, 2010
Messages
23,234
Motherboard
GA-X58A-UD7-F7
CPU
W3670
Graphics
RX 580
Mac
  1. iMac
  2. MacBook Pro
  3. Mac mini
Classic Mac
  1. iMac
Mobile Phone
  1. Android
However, if I were to buy an AMD GPU that's compatible with all the recent OSs (Mojave, Catalina and Big Sur), could I install that in my workstation (next to my existing GPU) and hard-wire it to only be used with OSX? The goal would be to have two GPUs, but only use one at any given time, i.e. nVidia for Linux & Windows, and AMD for MacOS.
I have heard of people doing this but never tried it myself. If you are going to purchase another GPU, best to get an AMD GPU that will perform as well as or better than the nVidia quadro card you now have and swap the new for the old. OTOH, there are still nVidia GPUs that are supported - see Dortania listing. You might be able to find one that will be comparable to the M5000, but it is doubtful as Mac support for nVidia GPUs has always been several years out of date, never having the latest GPU by a version or two, e.g. support for K5000, but not for M5000. The M5000 will outperform the K5000 by a good deal.
 
Last edited:
Top