Resolved Updated to Mojave... now I can't boot into my Windows volume

PianoPro

macrumors regular
Sep 4, 2018
232
118
Quite elegant, actually.

But now, with 10.14.4 and the new Boot Rom of 141.0.0.0.0, this elegant solution sadly doesn't seem to work anymore...

As I can't get to the EFI menu (and Windows 10) by holding down the option key at start, I'm a bit stuck.

Any suggestions as to how I might get this great Script to work again?

TIA...
I'm now using legacy-BIOS mode and that works fine with a script. I quit using Win 10 UEFI mode because of potential problems that may cause to the cMP. Which are you using and I can post my current script for you.
 

tyvol

macrumors newbie
Jan 7, 2009
20
6
Indio, California
I'm now using legacy-BIOS mode and that works fine with a script. I quit using Win 10 UEFI mode because of potential problems that may cause to the cMP. Which are you using and I can post my current script for you.
Wow!

I would be very appreciative if you could post your current script to get around the UEFI issue.

Most grateful, actually...
 

PianoPro

macrumors regular
Sep 4, 2018
232
118
Wow!

I would be very appreciative if you could post your current script to get around the UEFI issue.

Most grateful, actually...
Which script? To boot to Win 10 legacy-BIOS or to Win 10 UEFI mode?
[doublepost=1554515082][/doublepost]Here's my script (works with Mojave 10.14.4) for Win 10 Legacy-BIOS ONLY.

# Menubar Script for Mac Pro 5,1
# Reboots from Mac OS into Windows with legacy-BIOS ONLY. This script is NOT for Windows UEFI rebooting.
# A different script can be used for Windows UEFI rebooting, but Win10 UEFI booting is not recommended for MacPro 5,1.

# IMPORTANT - This script, like Reboot menu apps, requires SIP for the NVRAM to be disabled.
# To disable the SIP NVRAM boot into the recovery mode (hold cmd-R while restarting the Mac)
# and enter the following terminal command: csrutil enable --without nvram
# NOTE - PRAM reset will reenable the entire SIP and the script will cease to work until the SIP NVRAM is diaabled again.
# The entire SIP can also be reenabled from the recovery mode with the terminal command: csrutil enable

# Edit the following parameters in the script below for your Mac Pro -
# If the Windows volume name is not BOOTCAMP, then change BOOTCAMP (2 places) to your Windows volume name,
# but spaces are not permitted in the Windows volume name.
# Substitute your own password for "yourPassword" (enclose with " ") (2 places)

# This Script displays a dialog box with the choice of Once, Save, and Cancel buttons.
# Once - Restart from Win 10 will reboot to the previous OS X volume.
# Save - Restart from Win 10 will reboot to the Win 10 volume again (optional, see below).
# Cancel - will dismiss the dialog without rebooting.

# If you select Save you will NOT be able to reboot out of Windows unless you do a PRAM reset, or use
# the Windows Bootcamp Control panel to select a Mac OS boot volume. HOWEVER, the Bootcamp Control panel
# included with the Mac Pro 5,1 Bootcamp drivers no longer works with APFS volumes. But the Bootcamp Control panel
# included with the iMac Pro Bootcamp drivers (ver 6.1) will work. See MacRumors articles for installation method.

# If you do not install the iMac Pro Bootcamp Control panel you will not want to use the "Save" button option.
# You can delete the "Save" button in the next line, and the "else if (choice) = "Save"" block lines of the script below.


display dialog "Reboot to Windows 10 Legacy-BIOS" buttons {"Cancel", "Save", "Once"} # delete "Save", if desired

set choice to the button returned of the result as text

if (choice) = "Cancel" then
return


else if (choice) = "Once" then

# The line below creates an optional last chance to abort. Remove if desired

display dialog "Reboot to Windows Now & Reboot to Mac OS on Windows Restart"

# Change BOOTCAMP to the name of the Windows Volume in the line below, and substitute your password

do shell script "bless -mount /Volumes/BOOTCAMP -setBoot -nextonly -legacy" password "yourPassword" with administrator privileges

tell application "Finder" to restart


# delete the following lines if not using the optional "Save" button

else if (choice) = "Save" then

# The line below creates an optional last chance to abort. Remove if desired

display dialog "Reboot to Windows Now & Reboot to Windows on Windows Restart"

# Change BOOTCAMP to the name of the Windows Volume in the line below, and substitute your password

do shell script "bless -mount /Volumes/BOOTCAMP -setBoot -legacy" password "yourPassword" with administrator privileges

tell application "Finder" to restart

# end of the optional "Save" button deletion lines

end if
 
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tyvol

macrumors newbie
Jan 7, 2009
20
6
Indio, California
Which script? To boot to Win 10 legacy-BIOS or to Win 10 UEFI mode?
[doublepost=1554515082][/doublepost]Here's my script (works with Mojave 10.14.4) for Win 10 Legacy-BIOS ONLY.
This is extremely well thought out and the options included are exceptional!

I'll be working on it today, but I'm concerned that the Win 10 Legacy-BIOS only script approach may not recognize my High Point NVME SSD adapter.

If that's the case, I may have to go back to your Win 10 UEFI script and see how to make that work...

My worries aside, THANK YOU for your help and sharing of your knowledge in this area (and for your meticulous work in preparing it)!

I will report back after I adapt it and see what happens...
 
Last edited:

tyvol

macrumors newbie
Jan 7, 2009
20
6
Indio, California
Well, I reduced the suggested script around the options you offered, to (Windows is the Win 10 volume name):

display dialog "Reboot to Windows 10 Legacy-BIOS" buttons {"Cancel", "Once"}

set choice to the button returned of the result as text

if (choice) = "Cancel" then
return


else if (choice) = "Once" then
do shell script "bless -mount /Volumes/Windows -setBoot -nextonly -legacy" password "mypassword" with administrator privileges

tell application "Finder" to restart

end if

Ran it and it worked just fine, but after restart, this message appeared: "No boot disk present -- insert boot disk and press any key"

What I suspect happened is that this BIOS 'bless' approach jumped past my NVME High Point SSD adapter and tried to boot Windows from an Apricorn adapter housing a non-bootable Windows SSD (a Samsung EVO 850) which I use for Windows back up.

To be clear, my Windows 10 Pro SSD is not set up using BOOTCAMP and works fine this way.

My thinking is that your Win 10 UEFI mode script is the only option that can work for me and worked just fine under macOS 10.14.3 looking like this:

set Win_devID to do shell script "diskutil info Windows | grep Node"
# this assigns the string "Device Node: /dev/diskXsY" to the Win_devID variable, where X is unpredictable
# Windows is the Windows volume name

set Win_devID to (text -7 thru -2 of Win_devID) & "1"
# This strips everything except "diskXs" and appends a "1" for the EFI location (always "1")

display dialog "Windows EFI Volume was assigned as " & Win_devID buttons {"Cancel", "Boot Windows 10"}

do shell script "bless -device \"/dev/" & Win_devID & "\" -mount /Volumes/Windows -setBoot -nextonly" password "mypassword" with administrator privileges

tell application "Finder" to restart

Now under 10.14.4 when I run it and after restart, I get just a black screen and then the computer shuts down.


Any guidance as to why this great script no longer works, would be very much appreciated!
 

PianoPro

macrumors regular
Sep 4, 2018
232
118
Well, I reduced the suggested script around the options you offered, to (Windows is the Win 10 volume name):

display dialog "Reboot to Windows 10 Legacy-BIOS" buttons {"Cancel", "Once"}

set choice to the button returned of the result as text

if (choice) = "Cancel" then
return


else if (choice) = "Once" then
do shell script "bless -mount /Volumes/Windows -setBoot -nextonly -legacy" password "mypassword" with administrator privileges

tell application "Finder" to restart

end if

Ran it and it worked just fine, but after restart, this message appeared: "No boot disk present -- insert boot disk and press any key"

What I suspect happened is that this BIOS 'bless' approach jumped past my NVME High Point SSD adapter and tried to boot Windows from an Apricorn adapter housing a non-bootable Windows SSD (a Samsung EVO 850) which I use for Windows back up.

To be clear, my Windows 10 Pro SSD is not set up using BOOTCAMP and works fine this way.

My thinking is that your Win 10 UEFI mode script is the only option that can work for me and worked just fine under macOS 10.14.3 looking like this:

set Win_devID to do shell script "diskutil info Windows | grep Node"
# this assigns the string "Device Node: /dev/diskXsY" to the Win_devID variable, where X is unpredictable
# Windows is the Windows volume name

set Win_devID to (text -7 thru -2 of Win_devID) & "1"
# This strips everything except "diskXs" and appends a "1" for the EFI location (always "1")

display dialog "Windows EFI Volume was assigned as " & Win_devID buttons {"Cancel", "Boot Windows 10"}

do shell script "bless -device \"/dev/" & Win_devID & "\" -mount /Volumes/Windows -setBoot -nextonly" password "mypassword" with administrator privileges

tell application "Finder" to restart

Now under 10.14.4 when I run it and after restart, I get just a black screen and then the computer shuts down.


Any guidance as to why this great script no longer works, would be very much appreciated!
I don't know how Mojave is dealing with your NVME High Point SSD adapter, so I can't be of much help. However, I would do a "diskutil list" from the terminal and verify that your EFI location is indeed partition 1 of the disk. Other than that I have no ideas.
 

tyvol

macrumors newbie
Jan 7, 2009
20
6
Indio, California
Just to follow up...

I decided to go back to your 'elegant' boot Windows bless method EFI script and it now works most excellently under macOS 10.14.4 with ROM 141.0.0.0.0.

This major achievement was due to Alexandre's (tsialex's) reconstruction of my ROM back to the 140 version (what a gift! link here), using something called ROMtool (provided by tsialex) to reflash my ROM with the one he fixed and then mucho testing to be sure your Windows bless script worked again.

Then, just to prove that tsialex's guidance that ROM's are not often the cause of our problems, using my newly corrected ROM (that I managed to screw up), I upgraded my firmware (with macOS's full install of Mojave 10.14.4) and now your original and great EFI script works just fine!

Anyway, I wanted to express my appreciation to you for all of your help to sort out my problems (that I seemed to have managed to cause in the first place) and let you know how things turned out.

Thank you.

Cheers,

Al
 

tsialex

macrumors 603
Jun 13, 2016
5,307
6,025
Brazil
Just to follow up...

I decided to go back to your 'elegant' boot Windows bless method EFI script and it now works most excellently under macOS 10.14.4 with ROM 141.0.0.0.0.

This major achievement was due to Alexandre's (tsialex's) reconstruction of my ROM back to the 140 version (what a gift! link here), using something called ROMtool (provided by tsialex) to reflash my ROM with the one he fixed and then mucho testing to be sure your Windows bless script worked again.

Then, just to prove that tsialex's guidance that ROM's are not often the cause of our problems, using my newly corrected ROM (that I managed to screw up), I upgraded my firmware (with macOS's full install of Mojave 10.14.4) and now your original and great EFI script works just fine!

Anyway, I wanted to express my appreciation to you for all of your help to sort out my problems (that I seemed to have managed to cause in the first place) and let you know how things turned out.

Thank you.

Cheers,

Al
Just a correction, ROMTool is a @dosdude1 GUI/app, based on flashrom. All the merits go to dosdude1 and people who made flashrom, not me.
 
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danlivas

macrumors newbie
May 13, 2019
5
0
Is anyone familiar with this "Legacy mode not supported" message on a Mac Pro 5,1? Very strange, given I can legacy boot into the Windows drive if the macOS drive is removed. Otherwise, can't restart into Windows at all. The first screenshot is from the Applescript given in this thread, and the second screenshot is from Bootchamp. SIP is disabled, btw. Any help is appreciated.

EDIT: For some reason resetting the PRAM solved this issue. However, SIP did not re-enable itself. I don't know if at some point I permanently deactivated SIP. Oh well.
 

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Nessdufrat

macrumors regular
Jul 19, 2015
131
12
Between France and Switzerland
Hi guys, sorry to barge into this thread but I feel like I might be having a close enough problem. I upgrade to High Sierra (not Mojave but I believe that's the same kind of problem), and before that I had a fully working BootCamp install with Windows 7. I have a NVIDIA unflashed graphic card so no boot manager for me. I also have a PCIe SSD with NVME adapter, which was the reason for the High Sierra upgrade (as Sierra didn't recognise the SSD). After the upgrade, I can't boot into my Windows partition anymore.
I can see it in the startup manager as a choice, and if I click restart, I actually see the beginning of the windows start up, I see the infos about my graphic card, and then I get a black screen with a blinking cursor and nothing else happens. Only way to get back to Mac is to reset PRAM (obviously, by that point, I had switched to the original graphic card). Starting the mac and holding alt didn't do anything, it would again and again start in windows mode, ignoring the alt command and ending up with the blinking cursor.
I did a diskutil list and ending up with something really different, and besides, it's windows 7 and not windows 10 (with no intention whatsoever to upgrade because I just can't stand windows 10), and if there's no other solution, I'll go back to Sierra and get rid of the PCIe SSD (it came with the computer, I didn't buy it and don't really have any use for it, but since it was inside already, I thought it would be a waste not to use it. By get rid of, obviously I mean sell it, I won't throw it away, it's a 512Go SSD ^^). But if I can keep everything inside the computer, I'd rather have it that way.
I can't use a boot manager, because of the unflashed NVIDIA graphic card.
I don't mind wiping out either the windows partition or the mac partition. Both are brand new installs.
thanks for all advice! Diskutil list gave me something I never saw before, which was the synthesized disk, I don't know what that is. Bootdrive is the mac partition, Bootcamp is the windows partition. Apple_APFS container disk4 is also the bootdrive partition... External drive is the SSD PCIe. The others are a bunch of unrelated HD, some belong to the Windows partition and some to the mac partition. I also have another system running, which is called "The Beast Pro", which is a clone of my macbook pro that I needed while my computer was undergoing repairs. But for whatever reason, I was never able to boot to the windows partition from that one (it couldn't see "Bootcamp" in the startup manager).

diskutil.jpeg
 

danlivas

macrumors newbie
May 13, 2019
5
0
Hi guys, sorry to barge into this thread but I feel like I might be having a close enough problem. I upgrade to High Sierra (not Mojave but I believe that's the same kind of problem), and before that I had a fully working BootCamp install with Windows 7. I have a NVIDIA unflashed graphic card so no boot manager for me. I also have a PCIe SSD with NVME adapter, which was the reason for the High Sierra upgrade (as Sierra didn't recognise the SSD). After the upgrade, I can't boot into my Windows partition anymore.
I can see it in the startup manager as a choice, and if I click restart, I actually see the beginning of the windows start up, I see the infos about my graphic card, and then I get a black screen with a blinking cursor and nothing else happens. Only way to get back to Mac is to reset PRAM (obviously, by that point, I had switched to the original graphic card). Starting the mac and holding alt didn't do anything, it would again and again start in windows mode, ignoring the alt command and ending up with the blinking cursor.
I did a diskutil list and ending up with something really different, and besides, it's windows 7 and not windows 10 (with no intention whatsoever to upgrade because I just can't stand windows 10), and if there's no other solution, I'll go back to Sierra and get rid of the PCIe SSD (it came with the computer, I didn't buy it and don't really have any use for it, but since it was inside already, I thought it would be a waste not to use it. By get rid of, obviously I mean sell it, I won't throw it away, it's a 512Go SSD ^^). But if I can keep everything inside the computer, I'd rather have it that way.
I can't use a boot manager, because of the unflashed NVIDIA graphic card.
I don't mind wiping out either the windows partition or the mac partition. Both are brand new installs.
thanks for all advice! Diskutil list gave me something I never saw before, which was the synthesized disk, I don't know what that is. Bootdrive is the mac partition, Bootcamp is the windows partition. Apple_APFS container disk4 is also the bootdrive partition... External drive is the SSD PCIe. The others are a bunch of unrelated HD, some belong to the Windows partition and some to the mac partition. I also have another system running, which is called "The Beast Pro", which is a clone of my macbook pro that I needed while my computer was undergoing repairs. But for whatever reason, I was never able to boot to the windows partition from that one (it couldn't see "Bootcamp" in the startup manager).

View attachment 837089
I'm 90% sure you can't boot into the Windows partition of your startup drive on the Mac Pro 5,1 after High Sierra (because of the APFS conversion). I would try reinstalling Windows 7 to a dedicated, separate drive. You might also want to try restoring your existing Bootcamp partition to this dedicated drive using Winclone 6 or 7.
 
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Nessdufrat

macrumors regular
Jul 19, 2015
131
12
Between France and Switzerland
Right now I’m considering downgrading to Sierra. I can’t use a boot manager because of my Nvidia graphic card and I’ll always have troubles with boot camp if I have that APFS file system.
Also, the only dedicated drive where I could install windows would be my PCIe SSD, which isn’t recognized in Sierra (but I might have found some solution about that), and I also noticed that I was unable to install High Sierra on it, although it was seen by the system when I wanted to install the OS. My idea from the start was to use the PCIe SSD for high Sierra and the sata SSD for Windows. To each his own. But it wasn’t possible. High Sierra is viewing the PCIe as an external drive.

So, winclone? Seems promising. Would even allow me to take my fully working windows boot camp from my MacBook Pro and install it in the new Mac Pro, saving me hours of reinstalling every single program. Thanks for that, I didn’t know that program. I was so sad carbon copy cloner wasn’t able to properly clone windows partitions.
 

tsialex

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Jun 13, 2016
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Right now I’m considering downgrading to Sierra. I can’t use a boot manager because of my Nvidia graphic card and I’ll always have troubles with boot camp if I have that APFS file system.
This is not very wise. Apple supports the current macOS plus the two earlier versions, so Sierra supports ends this year, probably with one more Security Update around August/September timeframe. After 10.15 will be released, no more updates to Sierra. Security is so important nowadays and after Apple stops supporting Sierra, Chrome and Firefox will end it's support for it too, like what happened with El Capitan.

Don't use 3rd party kexts to make Sierra work with NVMe drives, you will open Pandora's KP box.

The best way to proceed is to install Windows with CSM mode and use iMac Pro BootCamp drivers to have Windows APFS support, then you can go back from and to Windows with ease without needing pre-boot configuration support (BootPicker).

Read here https://forums.macrumors.com/thread...ut-a-boot-screen.2114788/page-9#post-26689280

It's daunting to get all this right, but it's better that you do it now than having to do it in 3 months time.
[doublepost=1557937457][/doublepost]Btw, use a dedicated SATA drive for Windows.
 
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danlivas

macrumors newbie
May 13, 2019
5
0
Right now I’m considering downgrading to Sierra. I can’t use a boot manager because of my Nvidia graphic card and I’ll always have troubles with boot camp if I have that APFS file system.
Also, the only dedicated drive where I could install windows would be my PCIe SSD, which isn’t recognized in Sierra (but I might have found some solution about that), and I also noticed that I was unable to install High Sierra on it, although it was seen by the system when I wanted to install the OS. My idea from the start was to use the PCIe SSD for high Sierra and the sata SSD for Windows. To each his own. But it wasn’t possible. High Sierra is viewing the PCIe as an external drive.

So, winclone? Seems promising. Would even allow me to take my fully working windows boot camp from my MacBook Pro and install it in the new Mac Pro, saving me hours of reinstalling every single program. Thanks for that, I didn’t know that program. I was so sad carbon copy cloner wasn’t able to properly clone windows partitions.
Sierra has numerous issues that you want to stay away from, as tsialex points out. Apple even removed it entirely from the App Store shortly after releasing High Sierra, whilst keeping earlier OSes such as Capitan and Yosemite on the App Store. Sierra sucked.

As long as you have your Nvidia card installed, I would stay in High Sierra. APFS is a great friend but it doesn't work with Bootcamp on the same drive.

Before you clone or reinstall Windows, you can install Parallels (it's a 14 day complete trail). Configure it to boot from your Bootcamp Partition. If your Windows 7 starts up successfully within Parallels, then it will likely work when you use Winclone to clone it to another drive. If not, then I would reinstall Windows 7.

So here's the steps:

1. Test your current Bootcamp with Parallels 14. (AVOID SUBSEQUENT INSTALLATION OF PARALLELS TOOLS AT ALL COSTS)
2. If Windows works, clone your existing Bootcamp. If not, prepare to reinstall Windows from scratch.
3. Remove your Bootcamp partition from the startup drive since it won't be used anymore. Use Bootcamp Assistant.
4. Use Bootchamp 1.7 as a boot manager replacement.

BTW, I do not recommend using Winclone to clone Bootcamp partitions between Macs. It is unreliable.
 

Nessdufrat

macrumors regular
Jul 19, 2015
131
12
Between France and Switzerland
Thanks for all advice!
Would it be possible to use my NVMe SSD for High Sierra and my sata SSD for Windows? I don’t want to “sacrifice” another sata slot and buy a new sata SSD (I could obviously sell the NVMe SSD and buy a sata SSD with the money but that would mean losing one sata port and one of my HD drives) then, both OS would be on physically separate drives.

I’ll test my windows partition with parallel tomorrow. Too bad I can’t take the one from the MacBook Pro, that would have been so useful.

Edit : I’m seeing bootchamp doesn’t work in Sierra anymore? Am I seeing old info? The program seems like it was last updated in 2015, I might not work in high Sierra either. Is there an alternative?
 

Nessdufrat

macrumors regular
Jul 19, 2015
131
12
Between France and Switzerland
Thing is, at first, I tried to install high Sierra on the NVMe SSD and it wouldn’t let me. I tried twice before giving up and installing it on the sata SSD. No idea why. It would start the install, everything would go smoothly, then the computer would restart and go back to the same point, “install high Sierra” and tell me to select a drive.
 

tsialex

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Jun 13, 2016
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Thing is, at first, I tried to install high Sierra on the NVMe SSD and it wouldn’t let me. I tried twice before giving up and installing it on the sata SSD. No idea why. It would start the install, everything would go smoothly, then the computer would restart and go back to the same point, “install high Sierra” and tell me to select a drive.
What BootROM version your Mac Pro have?

Did you downloaded the High Sierra 10.13.6 from Mac App Store or used any else?
 

Nessdufrat

macrumors regular
Jul 19, 2015
131
12
Between France and Switzerland
I’d need to check that. But it’s been updated to the latest firmware.
High Sierra was downloaded from the App Store. I’d need to check whether it was the latest version available. Might not have been. I had it on a usb stick.

Btw, I found somebody on the forum with the same problem, apparently the startup manager is trying to boot windows in legacy mode and my windows is probably is efi mode. He is also getting the cursor of death.
Is there a way to get around that? Why wasn’t there an issue with Sierra and El Capitan ?
 

tsialex

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I’d need to check that. But it’s been updated to the latest firmware.
Current BootROM is 144.0.0.0.0, released yesterday afternoon with 10.14.5.

High Sierra was downloaded from the App Store. I’d need to check whether it was the latest version available. Might not have been. I had it on a usb stick.
High Sierra most recent Mac Pro BootROM is MP51.0089.B00 and this one don't support booting from NVMe. Apple starts NVMe boot support with 140.0.0.0.0, from Mojave 10.14.1.

Btw, I found somebody on the forum with the same problem, apparently the startup manager is trying to boot windows in legacy mode and my windows is probably is efi mode. He is also getting the cursor of death.
Is there a way to get around that? Why wasn’t there an issue with Sierra and El Capitan ?
UEFI Windows installs are not officially supported for MP5,1, just CSM/legacy installs. It's not an uncommon problem of UEFI installs causing havoc in the NVRAM and getting Mac Pros unbootable.
 

Nessdufrat

macrumors regular
Jul 19, 2015
131
12
Between France and Switzerland
Ok, so not the latest latest. But I did a firmware update maybe two weeks ago, I think. I’ll update to the latest one.
So no hope for my NVMe whatsoever. I’ll use it for my applications then.
I had no idea about the legacy and uefi installs. I do have windows on a dvd so I can reinstall it from there once I reinstall the whole setup. Weird that it was working perfectly fine for a year and a half before the high Sierra upgrade.
No possibility booting into uefi mode, I guess? It had to be legacy?
 

tsialex

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Ok, so not the latest latest. But I did a firmware update maybe two weeks ago, I think. I’ll update to the latest one.
So no hope for my NVMe whatsoever. I’ll use it for my applications then.
NVMe support is easy if you have a METAL compatible GPU to do the firmware upgrade. Read the first post of the thread MP5,1: What you have to do to upgrade to Mojave (BootROM upgrade instructions)

I had no idea about the legacy and uefi installs. I do have windows on a dvd so I can reinstall it from there once I reinstall the whole setup. Weird that it was working perfectly fine for a year and a half before the high Sierra upgrade.
No possibility booting into uefi mode, I guess? It had to be legacy?
Mac Pro supports only CSM installs and with UEFI you can't go back from Windows using iMac Pro APFS BootCamp drivers. So, if you have a GPU that don't have pre-boot configurations support (Mac EFI/support for boot screens) you have to do a CSM install.
 

tsialex

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Jun 13, 2016
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Nope, i have a Nvidia GTX980, unflashed.
Did you checked your BootROM version? AboutThisMac>SystemReport>HardwareOverview>BootROMVersion

Screen Shot 2019-05-15 at 18.58.10.png


Apparently I can change a UEFI install into a legacy once... just need to convert the partition using a program running from windows... ahahah.
Yes, there are software that makes the conversion too.