MP 1,1-5,1 Mac pro 5.1

[DPXLambo]

Mac Pro 5,1 - NVRAM writes fail despite healthy Boot ROM/VSS (Boot ROM 144.0.0.0.0)​

Hello everyone,

I'm hoping someone has seen this before.

Machine​

• Mac Pro 4,1 flashed to 5,1
• Dual Xeon X5690
• Radeon RX 580
• Mojave 10.14.6
• Boot ROM 144.0.0.0.0
• SMC 1.39f5

Problem​

The Mac boots and runs perfectly, but EFI/NVRAM writes fail.


Example:
<span>nvram </span><span>TestVariable</span><span>=</span><span>Hello</span>
returns
<span>nvram: Error setting variable - 'TestVariable': (iokit/common) general error</span>
The variable is never created.

Also:

• bless --setBoot cannot set efi-boot-device.
• OpenCore cannot become the default boot option.
• Software Update does not offer newer macOS installers.

Tests already performed​

• Replaced the CR2032 battery (3.2 V measured).
• Tested two completely different Mojave SSDs.
  • One with OpenCore.
  • One completely without OpenCore.
• Same behaviour on both.
• Disabled SIP from Recovery.
• csrutil status correctly reports disabled on the clean Mojave installation.
• nvram TestVariable=Hello still fails even with SIP disabled.

ROM Dump​

Using Macschrauber's ROM Dump:

• Boot ROM dumped successfully.
• Boot ROM version: 144.0.0.0.0
• VSS1 healthy.
• VSS2 healthy.
• CRC checks OK.
• Free VSS space available.
• No corruption reported by scanvss.

Flashrom reports normal SPI protection (FLOCKDN=1), but the ROM dump and analysis complete successfully.

Question​

Has anyone seen a Mac Pro where:

• the Boot ROM is healthy,
• the VSS store is healthy,
• but EFI runtime variable writes fail (nvram, bless, etc.)?

Is this a known firmware/runtime issue, or is there another diagnostic step I should perform before considering a firmware repair?

Thanks in advance.

 

[tsialex]

Replaced the CR2032 battery (3.2 V measured).

CR2032 is the wrong model of RTC battery, Mac Pros, iMacs and Mac minis all use the BR2032 one, since the internal temperature frequently is over the maximum allowed by the CR2032 chemistry formulation.

MacPro4,1/5,1 RTC battery is exactly below the GPU heatsink, with today's hindsight, one of worst places for it to be located.

[*]Software Update does not offer newer macOS installers.

This is unrelated, with Mojave you don't have any more softwareupdates since 2022, but not being capable of installing the downloaded updates is a classic symptom of failed SPI.

Is this a known firmware/runtime issue,

No.

Seems you have a failing SPI, with spent NAND cells.

or is there another diagnostic step I should perform before considering a firmware repair?

If you can't even bless and the RTC Battery is healthy, you have a hardware issue. You can try to run ASD/AHT and see if there are any errors elsewhere.

Seems you gonna need to replace the SPI flash memory, replace the backplane or buy a MATCard.

 

[DPXLambo]

Thank you for the explanation.
Since the ROM dump reports both VSS stores as healthy and CRCs are valid, would you expect a failing SPI chip to behave exactly like this, where reads are successful but all new EFI variable writes fail?
Also, would you recommend replacing the SPI flash chip only, or would you first try reflashing the existing chip externally with a programmer?

 

[tsialex]

Thank you for the explanation.
Since the ROM dump reports both VSS stores as healthy and CRCs are valid,

What this have anything to do with the cells being exhausted? Read is not the problem, but erasing and re-writing. The exhausted cells are inside the NVRAM area.

would you expect a failing SPI chip to behave exactly like this, where reads are successful but all new EFI variable writes fail?

Yep.

Also, would you recommend replacing the SPI flash chip only, or would you first try reflashing the existing chip externally with a programmer?

Re-flashing a failing SPI will most probably accomplish nothing, you will rewrite successfully since the majority of the SPI flash programmer are extremely slow when compared to the backplane and when you install it back, the same issue happens.

Never reinstall a SPI flash memory that is old enough to drive…

 

[DPXLambo]

Thank you very much for taking the time to look through my logs and explain everything so clearly.
I really appreciate your expertise and the detailed explanation. It helped me understand why the ROM dump can look healthy while the SPI flash itself may still be failing due to worn-out cells in the NVRAM area.
I'll follow your advice and replace the SPI flash rather than trying to reflash the existing one.
Thanks again for your time and for sharing your knowledge. It is very much appreciated.

 

[dexxter]

Hello everyone,

I'm hoping someone has seen this before.

• Mac Pro 5,1
• Intel xeon w3530
• Ati HD5770
• High sierra 10.13.6

After upgrading the computer from Sierra to High Sierra, it won't start. When I press the power button, a red light flashes inside the case, and then nothing happens. How should I deal with this?

 

[tsialex]

Hello everyone,

I'm hoping someone has seen this before.

• Mac Pro 5,1
• Intel xeon w3530
• Ati HD5770
• High sierra 10.13.6

After upgrading the computer from Sierra to High Sierra, it won't start. When I press the power button, a red light flashes inside the case, and then nothing happens. How should I deal with this?

Start with the DIAG LEDs, see what is lit or not.

 

[dexxter]

Start with the DIAG LEDs, see what is lit or not.

Thanks for your reply. The moment I plugged it in, the OVTMP light flashed red for a moment and then went out.Press the DIAG LED, only the 5V STBY light turns yellow, it won't light up if i don't press it. Nothing else happens, and the fan doesn't spin either.

 

[tsialex]

Thanks for your reply. The moment I plugged it in, the OVTMP light flashed red for a moment and then went out.Press the DIAG LED, only the 5V STBY light turns yellow, it won't light up if i don't press it. Nothing else happens, and the fan doesn't spin either.

Do you have another Mac Pro to test the PSU and the CPU tray?

You have to check everything, starting from the RTC battery. The most common failure is PSU, then CPU tray and last is the backplane, but with not even EFI_DONE and GPU_OK lit, could be the backplane.

 

[dexxter]

Do you have another Mac Pro to test the PSU and the CPU tray?

You have to check everything, starting from the RTC battery. The most common failure is PSU, then CPU tray and last is the backplane, but with not even EFI_DONE and GPU_OK lit, could be the backplane.

Thank you very much for replay.

 

[dexxter]

I've already replaced the RTC battery and the power supply, but there's still no response. It's probably more likely that the CPU tray is broken, but it could also be the backplane. Can I fix this myself, or do I need to take it in for repair?

 

[tsialex]

You can buy a backplane or CPU tray and replace yourself, take a look at the Apple Technician Guide.

Btw, it’s a lot cheaper to buy a whole Mac Pro of the same year than get each part, easier to diagnose too.

 

[dexxter]

👍

You can buy a backplane or CPU tray and replace yourself, take a look at the Apple Technician Guide.

Btw, it’s a lot cheaper to buy a whole Mac Pro of the same year than get each part, easier to diagnose too.

thank you. I just want to see if I can fix it; if not, then I won't. This old machine probably won't last long even if it's repaired.