Other Help on Mac Pro 5.1?

[romanof]

How could an NVMe PCI card wreck a Mac Pro 5.1?

Wanted to try a fast NVMe card in my Pro to see if I could tell a difference between it and an ordinary SSD. The answer turned out to be yes, unfortunately.

The Mac saw the card, loaded the OS just fine, but on reboot hung on restart with a chime, loud fans and nothing else. Taking the card out and replacing the SSD did not help. After a couple of hours of troubleshooting with SMC and PRAM restarts, it finally booted up - once.

But... Now on power up it may at random, 1 - do nothing but start the fans, 2 - start the fans and chime and then do nothing, 3 - start the fans and chime and, after many minutes, boot up, or 4 - boot up normally.

It is obvious that the NVMe adapter card changed something, but what?

Even tried it with Linux as a test. Finally got it to recognize the flash drive, loaded a bare copy of Debian just fine, rebooted and stalled with high fans and nothing.

I have very little experience in troubleshooting Cheesegraters - I have never had a failure with one. They just run and run.

Anybody got any ideas?

 

[MacintoshKeyboardHacking]

Maybe something got wiggled, you could try re-seating your other PCIe cards. Also, check the 'diag' button on the motherboard, that's all the status you get sometimes.

The symptoms sound like something I recently went through with my unit (the SPI flash failed, or got corrupt, same difference). Installing the new NVME would have created more, hidden, boot variables in NVRAM, possibly pushing the flash over the edge. You might plan to get a backup of the firmware the next time you get it booted.

EDIT: link to brief diag button overview https://forums.macrumors.com/thread...version-reference-table.2147538/post-26655246

 

[romanof]

Maybe something got wiggled, you could try re-seating your other PCIe cards. Also, check the 'diag' button on the motherboard, that's all the status you get sometimes.

Yeah, I have done that and more. I shucked down the PCI buss to nothing but the video card, and even changed that. Doing an SMC followed immediately by a PRAM sometimes brings it up, and once up it runs forever. Haven't messed with the firmware in a decade or more on any Cheesegrater and can't even remember how its done. Have to do some research.