MP 1,1-5,1 This Mac Pro 5.1 Saga has me tearing my hair out

[izools]

Last week I purchased a Mid 2012 Mac Pro 5.1

When I bought it it was Running Mojave, no Opencore, working perfectly.

2x 3.46Hz Six Core Xeons
64GB RAM
320GB HDD
2TB SSHD
1TB PCIe SSD
XFX Radeon HD7950 Double D with flashed Apple firmware

Worked perfectly, booting into Mojave natively, showing the Apple bootpicker just fine.

Having read up on Open Core, I decided I'd like to make this a dual boot system.

Created an OpenCore bootloader on the 320GB Drive, which is in Slot 1, created a Monterey installer on USB drive with OpenCore and installed Monterey without any fuss, booting fine via OpenCore, installed on the PCIe SSD, works a charm. Flawless.

Created Windows 11 installer with Rufus on a PC to remove the TPM checks etc

Booted off that via Open Core, attempted to install but kept getting error about "Unable to configure the drives for reboot" or similar, which I read was because the Windows installer gets confused about the other EFI partitions.

So I followed the guide to break out into a command prompt during install, use diskpart to edit the GUID of the other EFI partitions to standard volumes instead of system volumes, attempted to install again still got the same error.

So I obtained a 2TB SATA SSD, which I installed the Opencore bootloader onto
Rebooted the Mac with the 2TB SSD as the only drive in the machine, and used Opencore bootloader to start the Windows 11 installation from the Bootable USB, during install I allowed the Windows installer to erase all the partitions on the 2TB SSD

Installed fine, upon reboot I made sure to power down the Mac before it tried booting the Windows UEFI partition natively

Re-install the 320GB HDD in Slot 1 so that the Open Core bootloader on that drive was the first boot device it saw

Opencore boot loader loaded fine and allowed me to continue the windows installation from the 2TB SSD

Install completed successfully, however as soon as GPU drivers were installed, the display would go blank

I re-added the 1TB PCIe SSD, rebooted, and was able to boot back in to Monterey fine via Open Core

But any time I booted the Windows 11 drive via Open Core, Windows splash screen then blank screen

UEFI GOP I hear you say.

So I whipped out the GPU and put it in my Windows 11 desktop PC, booted fine, installed drivers fine, and was running in UEFI mode fine without any modifications.

I flashed the BIOS on the graphics card back to factory, found that the factory GPU BIOS didn't support UEFI GOP, so I used the GOP insertion tool to amend the factory firmware, reflashed it, rebooted in the PC to make sure it was all working well, everything was fine and dandy, so I put the card back in the Mac Pro

Mac Pro didn't display they grey screen any more on startup but did display Open Core bootloader fine. Attempted to boot in to Monterey, crashed during start up and powered off. Restarted the Mac, now it powers right off after the start up chime.

Took the card out and put it back in the PC, reflashed it back to the custom Mac firmware that was already on the card (I made sure to back it up before making any changes), rebooted the PC, still working fine, booting into Windows 11 without an issue.

Put the GPU back in the Mac, still I get as far as the start up chime then Mac powers itself off.

Attempted to do a PRAM reset but Mac powers itself off after 2nd start up chime.

Took the GPU back out boots fine in my Windows 11 PC, but the Mac Pro seems dead now, powers up, chimes, and powers down won't switch back on until you pull the power for a second.

I have a Pixlas mod and Radeon VII arriving tomorrow, I had hoped to run this in Windows 11 and Monterey as a dual boot system.

Oh - somewhere in amongst all of this I had also burned a DL-DVD of Windows 11 install to try installing it in non-UEFI mode, when booting from the DVD the Mac hangs on the windows splash screen.

And I've made sure never to let the Mac boot directly to a Windows 11 UEFI drive or installer - it's always been via Open Core - to avoid damage to the Apple firmware.

Not sure where to go now, other than to a corner to cry, and I'm fast running to hair to tear out

 

[tsialex]

Do you have a disk with a macOS release (10.6.4 to 10.14.6) that works? Remove all disks and install the one with macOS. Press the RTC reset button near the RTC battery for two seconds.

If you can boot it, do a deep NVRAM reset and see if you are back to normal. If after doing a multiple continuous NVRAM reset with a wired KB - press CMD-Option-P-R immediately after power up and keep it pressed until you hear the 5th chime (resetting the NVRAM continously 4x in sequence) - does not allow you to boot macOS, the most probable is that the Mac Pro BootROM is now corrupt.

If you have another Mac, install Mavericks to a spare disk, install the Mavericks to the HDD bay 1, disconnect the mains cable, remove the RTC battery, wait for two minutes, connect the mains cable (MacPro will power on automatically) then try to boot Mavericks.

If you can boot it, you proved that the BootROM have issues, since removing the RTC battery instructed the Mac Pro firmware to completely (temporarily, while the RTC battery is not installed) bypass the NVRAM volume inside the BootROM SPI flash memory - this is the firmware fail safe boot.

 

[izools]

Thanks a million! Will try when back home later

 

[tsialex]

Btw, to make this crystal clear, when trying the firmware fail-safe mode, the RTC battery needs to be uninstalled/disconnected from the battery holder.

Also, measure the RTC battery voltage with a voltmeter/multimeter and replace it with a new BR2032 if the voltage is below 3.00V. From factory the voltage is over 3.2V and gradually decrease over the years, then when below 3.00V the voltage drop is like jumping a cliff - the Mac Pro will start to behave crazily when the RTC battery is below something like 2,85V.

Never use a CR2032 as the Mac Pro RTC battery, besides the wrong discharge profile, the high temperatures below the GPU heatsink will cook the battery in months time. BR2032 have a different chemistry that tolerates up to 80ºC, while the CR2032 chemistry can only work up to 60ºC.

 

[izools]

You, sir, are a gent and a scholar.

Thank you. The Mac Pro is happy once again, and I have a new BR2032 on the way (measured 2.89v so not low enough to make me panic but low enough to order a replacement)

Performed the RTC reset after re-inserting the battery and then performed five PRAM reset cycles, everyting is booting beautifully now.

I won't try Windows 11 again until the Radeon VII I ordered arrives. Found a YouTube video with someone else experiencing the same blank screen after Win 11 installs drivers for the HD7950 - he was sensible and simply used a more recent card that is supported in both Mojave / Monterey and Win 11 instead of going down the rabbit hole I went down.

Fingies crossed!

And thanks again. Massively appreciated.

 

[izools]

Good news!

Radeon VII arrived and now Monterey / Windows 11 are running dual boot beautifully. Everything is working a charm.

That Radeon HD7950 really didn't like Windows 11 😆

Just waiting for a DP to Dual Link DVI adaptor to arrive now so I can resume using my 30" Cinema Display HD.

Thanks again for all your help.

 

[flat4]

Good news!

Radeon VII arrived and now Monterey / Windows 11 are running dual boot beautifully. Everything is working a charm.

That Radeon HD7950 really didn't like Windows 11 😆

Just waiting for a DP to Dual Link DVI adaptor to arrive now so I can resume using my 30" Cinema Display HD.

Thanks again for all your help.

up until recently I ran that same HD7950 what issues did you have?

I recently moved to a RX580, i often thought when my 5,1 would freeze in windows 11 it might have been the gpu or a usb 3.0 pcie card but could never figure it out.

 

[izools]

up until recently I ran that same HD7950 what issues did you have?

I recently moved to a RX580, i often thought when my 5,1 would freeze in windows 11 it might have been the gpu or a usb 3.0 pcie card but could never figure it out.

My 7950 caused windows 11 to flat out freeze when drivers were installed, black screen, and then sometimes a spontaneous reboot.

I did some more testing and the same HD7950 in a new PC (Ryzen 7 5700x) worked flawlessly, and in an older PC (HP Z620 workstation) refused to POST, with a graphics error beep code.

I can't be accurate on technicalities but it seems the combination of Windows 11, a Mac Pro 5.1, and an HD7950 just go into meltdown.

Has yours been behaving with the RX 580? 🙂

 

[flat4]

My 7950 caused windows 11 to flat out freeze when drivers were installed, black screen, and then sometimes a spontaneous reboot.

I did some more testing and the same HD7950 in a new PC (Ryzen 7 5700x) worked flawlessly, and in an older PC (HP Z620 workstation) refused to POST, with a graphics error beep code.

I can't be accurate on technicalities but it seems the combination of Windows 11, a Mac Pro 5.1, and an HD7950 just go into meltdown.

Has yours been behaving with the RX 580? 🙂

So far pretty good, I have not connected anything to the usb 3.0 card so that will be the true test, I did get the radeon software to install when I had the HD7950, use some old software that AMD said it did not exist, and possibly that could have caused the issues. However mine would just freeze sitting idle doing nothing.

Updated AMD software installed and so far no freezing. Mac os no issues either.

 

[izools]

I've got a usb 3.0 card working fine in mine, happy to check what chipset it had later if you like? I'm just using mine for a WiFi 6e adaptor. Works brilliantly... So far 😆

Glad your 580 is working well 🫡👍

 

[tsialex]

I'm just using mine for a WiFi 6e adaptor. Works brilliantly... So far 😆

Only for Windows/Linux? Or you found one that is supported by macOS?

macOS have extremely poor support for anything over 802.11ac that is not used by Apple with a Mac.

 

[izools]

Sorry for the delay replying, very rude.

The WiFi6 adaptor I use in Windows 11 since for whatever reason, under Win 11, the onboard WiFi won't connect to my home network, even though it does under Monterey.

Probably limited WPA3 support.