MP 1,1-5,1 MacPro5,1: BootROM thread | 144.0.0.0.0

[tsialex]

Hi, my Mac Pro 5,1 (mid 2012) yesterday started beeping while in use. After that it only beeps before the boot up sound. I have a reconstructed firmware. I refitted RAM, and I disconnected everything, exept my RX 580) and used another drive to update my reconstructed firmware with updated EnableGop 1,3 to 1,4. Made no difference, computer still beeps. Computer works as normal, boots fine and no crashes.

It beeps 2 quick beeps and then 10 not so quick beeps before the startup sound. Anyone knows what this beep code is about?

Thank you!

Weird, Macs only beep at POST:

If your Mac beeps during startup – Apple Support (UK)

Certain conditions related to memory or firmware may cause your Mac to beep once or more during startup.

support.apple.com

First I'd check if there are less RAM than it should, ECC errors can cause beeps at POST. Then I'd remove the main disk and then install macOS to a spare disk, to eliminate any software issues.

Also, some HDDs beep when failing.

 

[nnttq1]

Hello, bought 4.1 flashed to 5.1. Im already upgraded to RX570 and X5690. Tried to Enable GOP, got vss2 header error.

Spoiler: LOG

Firmware 144.0.0.0.0 (latest) built on Fri Apr 12 12:43:00 2019
Spoofed firmware version: 9999.999.999.999.999
(U)efi version: 1.10
MP41 backplane made in early 2009
CRC32 checksums: ok
Crossflash 4.1->5.1 (bootblock of MP51.007F.B03)
Base_18 hardware descriptor, Fsys 0x04
Fsys: 0 override-version, 1 overrides, 2 ssn, 3 hwc, 4 son, 5 EOF (ok)
Boot000x is EFI\OC\OpenCore.efi (LauncherOption: Full)
OCLP: 1.4.3 | -allow_fv | MacPro5,1
OpenCore is running, version: REL-099-2024-03-11
csr_Allow_Untrusted_Kexts, Unrestricted_FS, Unauthenticated_Root (0x803)
BootOrder: 1:Boot0001, 2:Boot0080
Boot0001: OpenCore |EFI|disk0s1 (PCI-Express Internal:NX-256 2280)|EFI|EFI\OC\OpenCore.efi
Boot0080: |EFI|disk0s1 (PCI-Express Internal:NX-256 2280)|EFI|\System\Library\CoreServices\boot.efi
Boot0081: Mac OS X \EFI\APPLE\FIRMWARE\EfiUpdaterApp2.efi "-x efi-apple-payload0-data -c 098adb07."
BootFFFF: |EFI|disk0s1 (PCI-Express Internal:NX-256 2280)|EFI|\System\Library\CoreServices\boot.efi
OCBtOrder: 1:OCBt0080, 2:OCBt0000
OCBt0000: Windows Boot Manager |EFI|disk2s1 (SATA Bay 4:Hitachi HDS721010CLA630)|NO NAME|\EFI\Microsoft\Boot\bootmgfw.efi WINDOWS..xBCDOBJECT={9dea862c-5cdd-4e70-acc1-f32b344d4795}a
OCBt0080: Macintosh HD_____ ____________ |Apple_APFS|disk0s2 (PCI-Express Internal:NX-256 2280)|\99EA458B-8CD8-41F2-B7B0-9ADFC8F05F72\System\Library\CoreServices\boot.efi
OCBt0080 is MacOs 14.5, label: Macintosh HD — данные
OCBt0081: Mac OS X MemoryMapped FvFile USB
efi-boot-device-data: \99EA458B-8CD8-41F2-B7B0-9ADFC8F05F72\System\Library\CoreServices\boot.efi
Find My Mac seems to be activated
3 firmware boots since last garbage collection, MTC counter: 284 - 286
VSS1 VSS2
1 (2 deleted) 1 Memory Configs g (ok)
1 (2 deleted) 1 Memory Configs h (ok)
1 (0 deleted) 1 Memory Configs i (ok)
1 (0 deleted) 1 Memory Configs j (ok)
1 (0 deleted) 1 Kernel Panic dumps type A: Pointer type
1 (0 deleted) 1 fmm-mobileme-token-FMM (ok)
1 (0 deleted) 1 fmm-mobileme-token-FMM-BridgeHasAccount (ok)
0 0 Microsoft certificates (ok)
1 (0 deleted) 1 BluetoothActiveControllerInfos (ok)
1 (0 deleted) 1 BluetoothInternalControllerInfos (ok)
0 (2 deleted) 1 Boot PathProperties0000 (ok)
1 (2 deleted) 1 NVRAM PathProperties0000 (ok)
1 (0 deleted) 1 csr-active-config (ok)
Length of 2nd VSS Store is wrong (FF FF FF FF)
35862 bytes free space of 65464
VSS1 (Formatted) (Healthy), found 83 variables (69 valid, 14 deleted)
VSS2 (Formatted) (VSS2 header problem), found 70 variables (70 valid)

Should I ignore vss problem and do Enable GOP or I need a repair?

 

[tsialex]

Hello, bought 4.1 flashed to 5.1. Im already upgraded to RX570 and X5690. Tried to Enable GOP, got vss2 header error.

Spoiler: LOG

Firmware 144.0.0.0.0 (latest) built on Fri Apr 12 12:43:00 2019
Spoofed firmware version: 9999.999.999.999.999
(U)efi version: 1.10
MP41 backplane made in early 2009
CRC32 checksums: ok
Crossflash 4.1->5.1 (bootblock of MP51.007F.B03)
Base_18 hardware descriptor, Fsys 0x04
Fsys: 0 override-version, 1 overrides, 2 ssn, 3 hwc, 4 son, 5 EOF (ok)
Boot000x is EFI\OC\OpenCore.efi (LauncherOption: Full)
OCLP: 1.4.3 | -allow_fv | MacPro5,1
OpenCore is running, version: REL-099-2024-03-11
csr_Allow_Untrusted_Kexts, Unrestricted_FS, Unauthenticated_Root (0x803)
BootOrder: 1:Boot0001, 2:Boot0080
Boot0001: OpenCore |EFI|disk0s1 (PCI-Express Internal:NX-256 2280)|EFI|EFI\OC\OpenCore.efi
Boot0080: |EFI|disk0s1 (PCI-Express Internal:NX-256 2280)|EFI|\System\Library\CoreServices\boot.efi
Boot0081: Mac OS X \EFI\APPLE\FIRMWARE\EfiUpdaterApp2.efi "-x efi-apple-payload0-data -c 098adb07."
BootFFFF: |EFI|disk0s1 (PCI-Express Internal:NX-256 2280)|EFI|\System\Library\CoreServices\boot.efi
OCBtOrder: 1:OCBt0080, 2:OCBt0000
OCBt0000: Windows Boot Manager |EFI|disk2s1 (SATA Bay 4:Hitachi HDS721010CLA630)|NO NAME|\EFI\Microsoft\Boot\bootmgfw.efi WINDOWS..xBCDOBJECT={9dea862c-5cdd-4e70-acc1-f32b344d4795}a
OCBt0080: Macintosh HD_____ ____________ |Apple_APFS|disk0s2 (PCI-Express Internal:NX-256 2280)|\99EA458B-8CD8-41F2-B7B0-9ADFC8F05F72\System\Library\CoreServices\boot.efi
OCBt0080 is MacOs 14.5, label: Macintosh HD — данные
OCBt0081: Mac OS X MemoryMapped FvFile USB
efi-boot-device-data: \99EA458B-8CD8-41F2-B7B0-9ADFC8F05F72\System\Library\CoreServices\boot.efi
Find My Mac seems to be activated
3 firmware boots since last garbage collection, MTC counter: 284 - 286
VSS1 VSS2
1 (2 deleted) 1 Memory Configs g (ok)
1 (2 deleted) 1 Memory Configs h (ok)
1 (0 deleted) 1 Memory Configs i (ok)
1 (0 deleted) 1 Memory Configs j (ok)
1 (0 deleted) 1 Kernel Panic dumps type A: Pointer type
1 (0 deleted) 1 fmm-mobileme-token-FMM (ok)
1 (0 deleted) 1 fmm-mobileme-token-FMM-BridgeHasAccount (ok)
0 0 Microsoft certificates (ok)
1 (0 deleted) 1 BluetoothActiveControllerInfos (ok)
1 (0 deleted) 1 BluetoothInternalControllerInfos (ok)
0 (2 deleted) 1 Boot PathProperties0000 (ok)
1 (2 deleted) 1 NVRAM PathProperties0000 (ok)
1 (0 deleted) 1 csr-active-config (ok)
Length of 2nd VSS Store is wrong (FF FF FF FF)
35862 bytes free space of 65464
VSS1 (Formatted) (Healthy), found 83 variables (69 valid, 14 deleted)
VSS2 (Formatted) (VSS2 header problem), found 70 variables (70 valid)

Should I ignore vss problem and do Enable GOP or I need a repair?

Do not inject EnableGop to a defective BootROM, try to do a NVRAM reset - most probably won't work since your Mac Pro is a cross-flashed early-2009 and you gonna need to repair it. I'll send you a PM.

 

[nnttq1]

So, I did nvram reset and vss2 fixed and got more free space, wonder how btw

 

[tsialex]

So, I did nvram reset and vss2 fixed and got more free space, wonder how btw

Sometimes you get lucky and the stars align.

Anyway, since this Mac Pro is an early-2009 cross-flashed, the NVRAM volume corruption will happen again later down the road.

 

[Conzpiral]

Weird, Macs only beep at POST:

If your Mac beeps during startup – Apple Support (UK)

Certain conditions related to memory or firmware may cause your Mac to beep once or more during startup.

support.apple.com

First I'd check if there are less RAM than it should, ECC errors can cause beeps at POST. Then I'd remove the main disk and then install macOS to a spare disk, to eliminate any software issues.

Also, some HDDs beep when failing.

Yesterday I had a complete hang working with some very very old Windows software with Codeweaver Crossover, had to force the computer off. After this my Mac Pro stopped beeping as I explained, now it seems just fine. Never had the time to start testing what it was about before this happened. I was going to try exchange my RX580 with my RX560 to see if this was the problem, but never needed to, for now... Go figure.

 

[JeffsTech]

Hello everyone! I've been hovering around these forums as I've been planning on getting one of these old 2009/2012 cheese grater Mac Pros, but I finally decided to make an account. I bought a few 2009 Mac Pros in a lot a few months ago and now I've finally gotten the opportunity to try and begin the upgrade/restoration process. I have ben trying to use the netkas firmware upgrade tool on a fresh install of El Capitan, but after trying a different boot drive, older version of Mac OS, DVI Apple Cinema display, PRAM reset, different CPU tray(s), different power button holding technique, blah blah blah, and nothing. I've probably seen the boot logo like 50 times at this point, the super drive doesn't eject, just back into the OS. I will say I'm impressed by the boot time given the age of everything-- anyways. I was told that there is an individual that goes by the name of @tsialex that may be able to help with a firmware upgrade. I don't know if rumors are true, but I've seen some posts on Reddit implying that the netkas tool is no longer functional. Nonetheless, I have a backup of my bootrom which is version B07.

If I could get a hand in getting my bootrom fixed and/or upgraded for 5, 1 so I can upgrade the CPUs, OCLP, graphics card etc, I would be eternally grateful.

Thanks!

 

[tsialex]

Hello everyone! I've been hovering around these forums as I've been planning on getting one of these old 2009/2012 cheese grater Mac Pros, but I finally decided to make an account. I bought a few 2009 Mac Pros in a lot a few months ago and now I've finally gotten the opportunity to try and begin the upgrade/restoration process. I have ben trying to use the netkas firmware upgrade tool on a fresh install of El Capitan, but after trying a different boot drive, older version of Mac OS, DVI Apple Cinema display, PRAM reset, different CPU tray(s), different power button holding technique, blah blah blah, and nothing. I've probably seen the boot logo like 50 times at this point, the super drive doesn't eject, just back into the OS.

This is nuts, why you tried 50 times for something that doesn't work for years already?

The only solution is the BootROM reconstruction service.

I will say I'm impressed by the boot time given the age of everything-- anyways. I was told that there is an individual that goes by the name of @tsialex that may be able to help with a firmware upgrade. I don't know if rumors are true, but I've seen some posts on Reddit implying that the netkas tool is no longer functional. Nonetheless, I have a backup of my bootrom which is version B07.

If I could get a hand in getting my bootrom fixed and/or upgraded for 5, 1 so I can upgrade the CPUs, OCLP, graphics card etc, I would be eternally grateful.

Thanks!

I'll send you a PM with all the info, required files, service fee and turnaround time.

 

[JeffsTech]

This is nuts, why you tried 50 times for something that doesn't work for years already?

The only solution is the BootROM reconstruction service.



I'll send you a PM with all the info, required files, service fee and turnaround time.

Okay, maybe I'm milking it, at most I did it like 20 times, but nonetheless I'll check your PM and hopefully we can get something figured out!

 

[48k Productions]

Hello @tsialex

I was sent here by MacSoundSolutions via youtube. I'm unfortunately having issues with my Mac Pro 5,1. After maxing out ram, upgrading GPU and installing Mojave, i no longer get a start up chime after attempting a PRAM reset. When I did the initial PRAM reset it only chimed once, after holding down the proper keys for at least ten minutes, I decided to power down and try again, which now the MP 5,1 won't do anything besides power on. MacSoundSolutions thinks it might be a bootrom issue. Thank you in advance!

 

[tsialex]

Hello @tsialex

Hi!

I'm unfortunately having issues with my Mac Pro 5,1. After maxing out ram, upgrading GPU and installing Mojave, i no longer get a start up chime after attempting a PRAM reset. When I did the initial PRAM reset it only chimed once, after holding down the proper keys for at least ten minutes, I decided to power down and try again, which now the MP 5,1 won't do anything besides power on. MacSoundSolutions thinks it might be a bootrom issue. Thank you in advance!

Did you still have EFI_DONE LED lit when you press the DIAG button? Please check it.

 

[48k Productions]

Hi!



Did you still have EFI_DONE LED lit when you press the DIAG button? Please check it.

It only flashes on momentarily as if it's cycling, the led below it turns on momentarily as well, right after the EFI_DONE LED lights up. The top most LED in that group stays lit as long as I hold DIAG

 

[tsialex]

It only flashes on momentarily as if it's cycling, the led below it turns on momentarily as well, right after the EFI_DONE LED lights up. The top most LED in that group stays lit as long as I hold DIAG

Seems you have a failed SPI flash memory or at least a hard brick.

The only thing that you can try now is to test with Firmware Fail-Safe mode:

• power off the Mac Pro.
• disconnect the PSU power cable.
• make the minimum configuration required for boot: remove all PCIe cards but the GPU, all PCIe disks, disconnect the cable from the DVD(s), disconnect all USB/firewire devices, all DIMMs but DIMM #1. Just keep 1 DIMM, the GPU (an AppleOEM GPU works best for this test), the disk with Mojave and the wired keyboard/mouse, uninstall/disconnect everything else.
• after a minute powered off, with the utmost care to not break the positive terminal, remove the RTC battery from the holder, keep it outside in a safe place, do not let it contact with anything conductive or it will discharge - also a good time to measure the voltage. Should be over 3.00V, below that it will require a replacement BR2032.
• wait a minute after uninstalling the RTC BR2032 battery and with the battery still removed from the RTC battery holder, connect the PSU power cable and press the Mac Pro power button as you do normally.

See if you get it to boot or at least to show something on the screen.

If you can get it to boot/show something on the screen (AppleOEM GPU practically a requirement for this), will be possible to repair the BootROM via BootROM reconstruction service.

If not, you will need to replace the SPI flash memory/install a MATT card/replace the backplane/etc.

 

[48k Productions]

Seems you have a failed SPI flash memory or at least a hard brick.

The only thing that you can try now is to test with Firmware Fail-Safe mode:

• power off the Mac Pro.
• disconnect the PSU power cable.
• make the minimum configuration required for boot: remove all PCIe cards but the GPU, all PCIe disks, disconnect the cable from the DVD(s), disconnect all USB/firewire devices, all DIMMs but DIMM #1. Just keep 1 DIMM, the GPU (an AppleOEM GPU works best for this test), the disk with Mojave and the wired keyboard/mouse, uninstall/disconnect everything else.
• after a minute powered off, with the utmost care to not break the positive terminal, remove the RTC battery from the holder, keep it outside in a safe place, do not let it contact with anything conductive or it will discharge - also a good time to measure the voltage. Should be over 3.00V, below that it will require a replacement BR2032.
• wait a minute after uninstalling the RTC BR2032 battery and with the battery still removed from the RTC battery holder, connect the PSU power cable and press the Mac Pro power button as you do normally.

See if you get it to boot or at least to show something on the screen.

If you can get it to boot/show something on the screen (AppleOEM GPU practically a requirement for this), will be possible to repair the BootROM via BootROM reconstruction service.

If not, you will need to replace the SPI flash memory/install a MATT card/replace the backplane/etc.

Thank you so much for the information. Unfortunately it looks like I'll be needing to replace the backplane (I saw your other thread about the three options when facing a corrupt bootrom, and replacing the backplane seems like the best option for me) I'm handy with soldering, but not when it comes to stuff like this

do you have any recommendations for reputable/reliable dealers for old Mac parts?

 

[tsialex]

Thank you so much for the information. Unfortunately it looks like I'll be needing to replace the backplane (I saw your other thread about the three options when facing a corrupt bootrom, and replacing the backplane seems like the best option for me) I'm handy with soldering, but not when it comes to stuff like this

Did you tried the Firmware Fail-Safe mode? Nothing on the screen? Is an early-2009 Mac Pro?

do you have any recommendations for reputable/reliable dealers for old Mac parts?

Unfortunately anything that I can recommend will be useless for people outside this side of globe. Said that, DV Warehouse seems to have decent parts for people in the USA, but the last time I've shopped from them was at least 4 years ago:

early-2009:

https://www.dvwarehouse.com/apple/661-5444-apple-backplane-board-version-2-for-mac-pro-early-2009.html

mid-2010/mid-2012:

https://www.dvwarehouse.com/apple/661-5706-apple-backplane-board-for-mac-pro-5-1-mid-2010-mid-2012-820-2337-a.html

Buy the correct one for the CPU tray you have. An early-2009 CPU tray only works with an early-2009 backplane.

Btw, once burned and to avoid a future brick, the BootROM reconstruction service is something that you should think about, even more so with a 2nd hand backplane that you know nothing about the history of it.

 

[crjackson2134]

Did you tried the Firmware Fail-Safe mode? Nothing on the screen?

I for one, would like to hear the answer to this as well. The backplane may indeed be fine, and snapping in a MATT card with a reconstructed Firmware would be much easier (At least for me).

As you know, I’ve had 3 backplanes in my MP51 (counting the original), and I’ve installed a MATT card (as a preventative to SPI failure) also. With my modest skill set & abilities, I’d rather install a MATT card w/reconstructed Firmeware than replacing a backplane. It was far simpler in my case.

 

[48k Productions]

Did you tried the Firmware Fail-Safe mode? Nothing on the screen? Is an early-2009 Mac Pro?



Unfortunately anything that I can recommend will be useless for people outside this side of globe. Said that, DV Warehouse seems to have decent parts for people in the USA, but the last time I've shopped from them was at least 4 years ago:

early-2009:

https://www.dvwarehouse.com/apple/661-5444-apple-backplane-board-version-2-for-mac-pro-early-2009.html

mid-2010/mid-2012:

https://www.dvwarehouse.com/apple/661-5706-apple-backplane-board-for-mac-pro-5-1-mid-2010-mid-2012-820-2337-a.html

Buy the correct one for the CPU tray you have. An early-2009 CPU tray only works with an early-2009 backplane.

Btw, once burned and to avoid a future brick, the BootROM reconstruction service is something that you should think about, even more so with a 2nd hand backplane that you know nothing about the history of it.

Ha! That’s the distributor that I have bookmarked for that same 2010 2012 listing. Currently waiting to hear back on what “refurbished” means in this context.

Much appreciated for the advice and your time. Is the BootROM reconstruction service something you offer/sell? I definitely don’t want to be regularly replacing backplanes lol

 

[48k Productions]

Did you tried the Firmware Fail-Safe mode? Nothing on the screen? Is an early-2009 Mac Pro?



Unfortunately anything that I can recommend will be useless for people outside this side of globe. Said that, DV Warehouse seems to have decent parts for people in the USA, but the last time I've shopped from them was at least 4 years ago:

early-2009:

https://www.dvwarehouse.com/apple/661-5444-apple-backplane-board-version-2-for-mac-pro-early-2009.html

mid-2010/mid-2012:

https://www.dvwarehouse.com/apple/661-5706-apple-backplane-board-for-mac-pro-5-1-mid-2010-mid-2012-820-2337-a.html

Buy the correct one for the CPU tray you have. An early-2009 CPU tray only works with an early-2009 backplane.

Btw, once burned and to avoid a future brick, the BootROM reconstruction service is something that you should think about, even more so with a 2nd hand backplane that you know nothing about the history of it.

Sorry, I missed the question about fail-safe mode, yes, I followed your instructions and unfortunately nothing came up on screen and no chime. The fan of the GPU would just go back and forth between slightly different speeds (which when holding the DIAG button down seemed to cycle speeds with the leds you asked about earlier.

and lastly, it’s a mid 2012

 

[48k Productions]

I for one, would like to hear the answer to this as well. The backplane may indeed be fine, and snapping in a MATT card with a reconstructed Firmware would be much easier (At least for me).

As you know, I’ve had 3 backplanes in my MP51 (counting the original), and I’ve installed a MATT card (as a preventative to SPI failure) also. With my modest skill set & abilities, I’d rather install a MATT card w/reconstructed Firmeware. It was far simpler in my case.

From what I read though, the MATT doesn’t allow iCloud/message functionality (if I’m remembering correctly)

 

[crjackson2134]

From what I read though, the MATT doesn’t allow iCloud/message functionality (if I’m remembering correctly)

Incorrect (provided you flash it with your own reconstructed Firmware).

As shipped, you will have that issue if you don’t complete the task of updating the firmware.

Doing the repair properly involves flashing the MATT card with the firmware for YOUR machine. The copy on the chip only gets you booting. From there, reflash YOUR machines firmware (reconstructed) to the MATT card, and it’s like the whole problem never existed.

 

[tsialex]

I for one, would like to hear the answer to this as well. The backplane may indeed be fine, and snapping in a MATT card with a reconstructed Firmware would be much easier if this is the case.

Maybe not important for him, but people that have software licenses that validate/locked to the hardware, the replacement backplane will be a headache.

Some people even replace the Ethernet SPI flashes with the ones from the failed backplane just to avoid all the headache with re-licencing, keeping the same MAC addresses with the replacement backplane.

There are licenses that are not possible to re-license today.

Is the BootROM reconstruction service something you offer/sell? I definitely don’t want to be regularly replacing backplanes lol

Yes, I'll send you a PM with all the info.

From what I read though, the MATT doesn’t allow iCloud/message functionality (if I’m remembering correctly)

You just have to flash back the reconstructed BootROM to the MATT card. It's possible to dump the factory SPI after you get it booting again and then repair it.

See what is easier/cheaper for you.

 

[48k Productions]

Incorrect (provided you flash it with your own reconstructed Firmware).

As shipped, you will have that issue if you don’t complete the task of updating the firmware.

Doing the repair properly involves flashing the MATT card with the firmware for YOUR machine. The copy on the chip only gets you booting. From there, reflash YOUR machines firmware (reconstructed) to the MATT card, and it’s like the whole problem never existed.

Ohhhhhh, awesome, thanks for clarifying! Sorry for the ignorance, but the MATT card is something i buy to be able to successfully boot, then I do the firmware update via OSX/terminal?

Super appreciate the input. I left the Mac world quite a while ago due to Apple’s poor choices, but got this Mac Pro 5,1 for free and didn’t even realize how many OSX’s have released since then. Not ONE application that I use for work is supported on Mojave, so I was pleased to learn about opencore options, otherwise I’d be stuck installing windows 10 on it if I even wanted to use it lol

 

[tsialex]

Ohhhhhh, awesome, thanks for clarifying! Sorry for the ignorance, but the MATT card is something i buy to be able to successfully boot, then I do the firmware update via OSX/terminal?

MATT card is a SPI flash replacement board from cmizapper, from factory it already have a mid-2010 BootROM image, that you need to replace with your own later.

Once installed and your Mac Pro is booting again correctly, you flash it via flashrom/ROMTool/etc.

 

[48k Productions]

MATT card is a SPI flash replacement board from cmizapper, from factory it already have a mid-2010 BootROM image, that you need to replace with your own later.

Once installed and your Mac Pro is booting again correctly, you flash it via flashrom/ROMTool/etc.

It seems like getting the MATT card would be a good thing to have on hand regardless of what approach I decide to take, no? Only downside I see is that if it didn’t work for whatever reason, it would’ve been cheaper to replace the backplane 😅

 

[tsialex]

It seems like getting the MATT card would be a good thing to have on hand regardless of what approach I decide to take, no? Only downside I see is that if it didn’t work for whatever reason, it would’ve been cheaper to replace the backplane 😅

MATT card is very useful for diagnostics, a must for someone that have more than one Mac Pro.

Maybe the cost of a MATT card + BootROM reconstruction service + the possibility of having to replace the backplane doesn't make much economical sense to you, since you seem to do not have software licenses to care.