MP 1,1-5,1 MacPro 5,1 Windows 10 installation and BootROM

[mikiotty]

Hi everyone!
I finally acquired my MacPro 5,1, and I'm now trying to install Windows 10.
I currently run Monterey with the latest OpenCore on an NVMe PCIe SSD. OpenCore is installed on the same volume. I want to install Windows 10 on a SATA SSD, I don't really care about UEFI mode but I read about BootROM corruption in some cases. Can I install Windows in Legacy mode (taking out my NVMe SSD temporarily) and be completely safe?
Thank you!

 

[Macschrauber]

avoid Windows installers from USB drives and with EFI in the name. Install from DVD or with the bare metal method using a virtualisation app installing on a real disk image.

Make a bootrom backup before, in case you messed it with certificates you can flash it back.

I made a tool for that

https://forums.macrumors.com/threads/healthy-nvram-normal-behaviour-on-4-1-5-1-machines.2333460/post-31857693

 

[mikiotty]

avoid everything USB and with EFI in the name. Install from DVD or with the bare metal method using a virtualisation app installing on a real disk image.

Make a bootrom backup before, in case you messed it with certificates you can flash it back.

I made a tool for that

https://forums.macrumors.com/threads/healthy-nvram-normal-behaviour-on-4-1-5-1-machines.2333460/post-31857693

So basically even before OpenCore, with native Mojave, there was the risk to brick the system by installing Windows from a USB drive (created from BootCamp Assistant)? That's scary...

 

[Macschrauber]

you got that wrong, with USB drive I meant installing Windows from an USB drive. Will correct that.

Bootcamp is not working for classic Mac Pros since a long time.

 

[mikiotty]

you got that wrong, with USB drive I meant installing Windows from an USB drive. Will correct that.

Bootcamp is not working for classic Mac Pros since a long time.

If I take a completely original Mac Pro 5,1, with the latest BootROM 144.0.0.0, with Mojave (officially supported), I cannot use BootCamp Assistant to install Windows on an internal SATA drive with a USB Windows installer created from the BootCamp Assistant app?

 

[Macschrauber]

The classic Mac Pro can only boot USB Windows Installers in Uefi Mode, so if you just once boot an USB thumb drive with an Windows installer on it you get a certificate. Even if you just boot the installer without installing Windows.

So the fix is

a) use OpenCore and Uefi Windows
b) use Legacy Windows

in every case make a bootrom backup before, you can flash it back if certificates got in.

 

[mikiotty]

The classic Mac Pro can only boot USB Windows Installers in Uefi Mode, so if you just once boot an USB thumb drive with an Windows installer on it you get a certificate. Even if you just boot the installer without installing Windows.

So the fix is

a) use OpenCore and Uefi Windows
b) use Legacy Windows

in every case make a bootrom backup before, you can flash it back if certificates got in.

Got it. How can I flash the BootROM back if I cannot boot the Mac anymore?

 

[Macschrauber]

If I take a completely original Mac Pro 5,1, with the latest BootROM 144.0.0.0, with Mojave (officially supported), I cannot use BootCamp Assistant to install Windows on an internal SATA drive with a USB Windows installer created from the BootCamp Assistant app?

You cannot create a USB Windows installer with Bootcamp on a Mac Pro. Afair the USB Stick was not an installer, it held just the drivers.

Forget Bootcamp, install Windows natively like on a real PC.

 

[Macschrauber]

Got it. How can I flash the BootROM back if I cannot boot the Mac anymore?

if you are on 144.0.0.0 you will not brick the Mac Pro instantly, it will confuse the NVRAM, exactly the circular cleaning of it.

Bricking it instantly happened with firmware MP51.0087.B00 what came with 10.13.5

so be prepared, backup the bootrom, avoid Uefi (or use OpenCore what protects the NVRAM against Windows certificates)

 

[mikiotty]

if you are on 144.0.0.0 you will not brick the Mac Pro instantly, it will confuse the NVRAM, exactly the circular cleaning of it.

Bricking it instantly happened with firmware MP51.0087.B00 what came with 10.13.5

so be prepared, backup the bootrom, avoid Uefi (or use OpenCore what protects the NVRAM against Windows certificates)

Got it. How can I tell if it bricks?
Which option do you advice, considering that I have an RX6600 with no boot screen in the Mac? I can put back the R9 280X just for installation which shows a bootscreen, to install in Legacy mode, but it will be difficult to switch to Windows if I cannot see the bootscreen.

 

[Macschrauber]

Check out RefindPlus as an bootloader what provides a bootscreen if the GPU has a proper GOP driver in it.

GitHub - dakanji/RefindPlus: A Boot Manager for Mac and PC

A Boot Manager for Mac and PC. Contribute to dakanji/RefindPlus development by creating an account on GitHub.

github.com

If you run Mojave and legacy Windows you will not need OpenCore.

 

[Macschrauber]

Got it. How can I tell if it bricks?

My Dumper finds certificates and reports it.

 

[mikiotty]

Hi! Just for information, I ran your tool on my dumped BootROM and this is the result. If I understand correctly, I may need to flash a reconstructed BootROM on my Mac Pro to avoid it bricking just by using it.
I also noticed the "Old bootblock of MP51.007F.B03". Will this cause me instant bricks with Windows in UEFI mode, if I accidentally boot Windows without OpenCore?

 

[Macschrauber]

Hi! Just for information, I ran your tool on my dumped BootROM and this is the result. If I understand correctly, I may need to flash a reconstructed BootROM on my Mac Pro to avoid it bricking just by using it.
I also noticed the "Old bootblock of MP51.007F.B03". Will this cause me instant bricks with Windows in UEFI mode, if I accidentally boot Windows without OpenCore?

no

- you have the latest firmware (144.0.0.0)
- you have no certificates, so you have a "clean" bootrom backup. In case you will get certificates you can flash that back.

- that "Old bootblock of MP51.007F.B03" is just the boot block module in the firmware. That never gets updated by regular firmware updates. Only with manual reconstructions. The benefit in a new boot block is mainly with some PCIe Cards. Does have nothing to do with the bricks.

MP51.007F.B03 was the first firmware what has been flashed into your Mac Pro by factory and the boot block never got updated. This is the expected behaviour.

 

[mikiotty]

Thank you!
How would you judge this bootrom? Is it healthy?

 

[Macschrauber]

the behaviour of a working NVRAM circular cleanup is shown here (it's a while ago, active/inactive variables are not separated):

https://forums.macrumors.com/threads/healthy-nvram-normal-behaviour-on-4-1-5-1-machines.2333460/page-2?post=30829975#post-30829975

so if you reboot regular a few times free space lowers until it gets below 2000 and then the regular NVRAM garbage collection runs and clears inactive variables. Free space is back to 40 to 50k





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If you want to do a manually integrity check of the NVRAM do a triple nvram reset in one row (hold alt-cmd-p-r together until the box chimes four times).

VSS2 gets cleaned
all VSS1 inactive variables get cleaned
one set of active variables should appear
free space should be something about 40 to 50k


be prepared to re-bless your bootloader as it clears the most NVRAM variables completely