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macOS 10.14.X/WIN10/Linux UEFI Multiboot on separate 2 x nvme pcie SSD + 1 x Sata SSD

Joined
Nov 18, 2015
Messages
118
Motherboard
Gigabyte Z390 Designare
CPU
i9-9900K
Graphics
RX 580
Hi All,
I installed my current triple boot system (macOS 10.13.6/WIN10/Linux Clover Legacy) on a 1 x Sata SSD + 2 x Sata HDD connecting each time only the drive affected by each O.S. installation and installing Clover boot loader on the masOS Sata SSD.
Now in my new build (Gigabyte Z390 Designare - Intel i9 - 9900K) I have the possibility of using the 2 x M.2 slots with nvme pcie drives that are faster but not so easy to disconnect during the installation phases of each O.S..
It would be possible to realize such a triple boot system without disconnecting each/both the two M.2 nvme pcie SSD drives during the installation?
Thanks in advance for Your help
 

Going Bald

Moderator
Joined
Aug 14, 2010
Messages
22,560
Motherboard
GA-X58A-UD7 Rev.1 BIOS F7
CPU
Intel Xeon W3670
Graphics
RX580
Mac
iMac, MacBook Pro, Mac mini
Classic Mac
iMac
Yes, you can. See if your manual can tell you which drive is recognized first when the system scan is done on power on. Usually this will be the one closest to the CPU, but not always. One way to tell is to install both drives and install Windows on one of them. If the EFI and boot files are on one drive and the OS is on the other, you guessed wrong. Secure erase the one the OS is installed on and reinstall to the other. If the OS is totally on the drive you installed on you have it made. The goal here is to make Win10 happy with its position in the boot order - it always wants to be on the first drive and updates have been known to overwrite the Mac OS EFI if it is the first drive. Once you have Win10 installed and updated, install Mac OS on the second drive, reboot to UEFI and make the Mac drive first in BBS boot order.
 
Joined
Nov 18, 2015
Messages
118
Motherboard
Gigabyte Z390 Designare
CPU
i9-9900K
Graphics
RX 580
Yes, you can. See if your manual can tell you which drive is recognized first when the system scan is done on power on. Usually this will be the one closest to the CPU, but not always. One way to tell is to install both drives and install Windows on one of them. If the EFI and boot files are on one drive and the OS is on the other, you guessed wrong. Secure erase the one the OS is installed on and reinstall to the other. If the OS is totally on the drive you installed on you have it made. The goal here is to make Win10 happy with its position in the boot order - it always wants to be on the first drive and updates have been known to overwrite the Mac OS EFI if it is the first drive. Once you have Win10 installed and updated, install Mac OS on the second drive, reboot to UEFI and make the Mac drive first in BBS boot order.
Thank You for Your reply
I have already installed macOS Mojave on the M2M connector, if I had to reposition it, according to your explanations, on the M2P connector, can I do it without other changes or should I reinstall it?
M2M-M2P.PNG
In your experience, in a multiboot UEFI system (macOS/Windows10/Linux), could Linux create rewrite problems for the EFI partition on which the Clover Bootloader is installed (macOS drive)?
 

Going Bald

Moderator
Joined
Aug 14, 2010
Messages
22,560
Motherboard
GA-X58A-UD7 Rev.1 BIOS F7
CPU
Intel Xeon W3670
Graphics
RX580
Mac
iMac, MacBook Pro, Mac mini
Classic Mac
iMac
Linux will give you no problems as it installs boot files where you tell it to, and updates them in that location.
 
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