MP 1,1-5,1 Mac Pro won't POST or boot.

[tcprado]

I have a Mac Pro that I bought as 5,1, the logic board is a 820-2337-A which i understand is a 2009 4,1 board.

All was well and I flashed a R9 270 GPU EFI to work with it and it did, booted and everything. After that boot, I turned it off, closed the lid and boom! Won't boot anymore. In fact it won't POST. Both CPU red LEDs come on, no fan spin, and it turns off. I have tried removing every accessory and nothing happens. I have not yet replaced the CPUs.

Video of issue

I think I need to reflash the EFI. Any advice?

 

[Macschrauber]

pull the gpu and listen if it chimes, maybe the gpu gone south

 

[mattspace]

RealTime Clock reset is a good first stop for boot problems. Little button is up near the motherboard battery.

 

[tcprado]

I've been away for a few days. I've tried both without success.
I've tried a new CR2032 battery and a different GPU (RX 580 that I was using and the stock GT 120). Problem persists.

 

[tcprado]

So, I've tried both suggestions already. No success. Any other insights?

 

[tcprado]

RealTime Clock reset is a good first stop for boot problems. Little button is up near the motherboard battery.

I tired that without success. I have the same as yours: 4,1 -> 5,1 with sapphire RX 580. I also tried a new CR2032. Any other ideas?

 

[mattspace]

I tired that without success. I have the same as yours: 4,1 -> 5,1 with sapphire RX 580. I also tried a new CR2032. Any other ideas?

Do you have the service manual, and have you followed its processes? That's probably your best bet for isolating where the problem is.

 

[tcprado]

Do you have the service manual, and have you followed its processes? That's probably your best bet for isolating where the problem is.

I did, I'm at the point of removing the CPUs now to see if there is something wrong. The only thing is that when I follow the barebones procedure, as soon as I get to the point where the fans were supposed to spin, they don't.

 

[tcprado]

Do you have the service manual, and have you followed its processes? That's probably your best bet for isolating where the problem is.

OK, I removed the CPUs and the fans spin as they're supposed to. When I reinsert the CPU (even just CPU A) it gets to the same behavior. With no CPU the white LED comes on in the front panel, the fans spin as they should. I'll have to replace the CPUs.

 

[Macschrauber]

In this case I vote for the CPU board.

 

[tcprado]

I bought a new CPU tray. Let's see how it performs.

 

[tcprado]

It's been a while. I bought a new Mac Pro 5,1 (2010) and the CPU tray from the old one (faulty one) works flawlessly on the new (to me) Mac Pro. The CPU tray from the new one still causes the same issue on the old one. Any insights?

That happened right after I successfully installed OpenCore and flashed a R9 270 2GB (also successfully). One or two reboots later, this happened. I'm wondering if it could be something related to the BOOT ROM, perhaps?

 

[Macschrauber]

if you want to exclude the boot rom backup you rom with romTool,

Dump the rom from the good one and flash it to the other one.

Dont ever do this without a backup, the boot rom contains data like serial number, board ids and so on.

it's just for a test, don't run two machines with the same serial number / identity. If the rom is the culprit than it needs reconstruction with its own machine datas.

 

[tsialex]

It's been a while. I bought a new Mac Pro 5,1 (2010) and the CPU tray from the old one (faulty one) works flawlessly on the new (to me) Mac Pro. The CPU tray from the new one still causes the same issue on the old one. Any insights?

That happened right after I successfully installed OpenCore and flashed a R9 270 2GB (also successfully). One or two reboots later, this happened. I'm wondering if it could be something related to the BOOT ROM, perhaps?

CPU trays don't have any firmware that you can flash, no BootROM and no user replaceable components.

It's the backplane that have BootROM, if the new CPU tray makes your old Mac Pro to work, the old one is defective.

If the new CPU tray don't, then you could have a defective backplane or even a defective PSU. Time to test both components with your working Mac Pro.

 

[tcprado]

CPU trays don't have any firmware that you can flash, no BootROM and no user replaceable components.

It's the backplane that have BootROM, if the new CPU tray makes your old Mac Pro to work, the old one is defective.

If the new CPU tray don't, then you could have a defective backplane or even a defective PSU. Time to test both components with your working Mac Pro.

Thanks, I know the tray doesn't have BootROM, I was wondering if the backpane BootROM got messed up. If it did, how can I repair it if it doesn't turn on at all? I'll try the PSU first as it's easier

 

[tcprado]

if you want to exclude the boot rom backup you rom with romTool,

Dump the rom from the good one and flash it to the other one.

Dont ever do this without a backup, the boot rom contains data like serial number, board ids and so on.

it's just for a test, don't run two machines with the same serial number / identity. If the rom is the culprit than it needs reconstruction with its own machine datas.

Thanks, how would I do that? How do I backup the boot ROM if it won't power on?

I have a BIOS programmer that I successfully used to restore an HP computer, could I use that?

 

[tsialex]

Thanks, how would I do that? How do I backup the boot ROM if it won't power on?

You have to desolder the SPI flash memory, U8700, and dump/program it externally.

I have a BIOS programmer that I successfully used to restore an HP computer, could I use that?

You have to use a SPI flash programmer, not a all EEPROM/EPROM programmers can program SPI flash memories.

Read the "What to do if during the upgrade process your Mac Pro bricked:" part of the first post of the thread below:

MP5,1: What you have to do to upgrade to Mojave (BootROM upgrade instructions thread)

Please fully read this first post, you will probably find that you have one or more problems described into the various notes below. Mojave will only install if you have upgraded your BootROM to the current release and your Mac Pro have a Metal capable GPU*. If you are trying to install Mojave...

forums.macrumors.com

 

[tcprado]

You have to desolder the SPI flash memory, U8700, and dump/program it externally.

You have to use a SPI flash programmer, not a all EEPROM/EPROM programmers can program SPI flash memories.

Read the "What to do if during the upgrade process your Mac Pro bricked:" part of the first post of the thread below:

MP5,1: What you have to do to upgrade to Mojave (BootROM upgrade instructions thread)

Please fully read this first post, you will probably find that you have one or more problems described into the various notes below. Mojave will only install if you have upgraded your BootROM to the current release and your Mac Pro have a Metal capable GPU*. If you are trying to install Mojave...

forums.macrumors.com

BIG THANKS!

So, mine was already on 144.0.0.0.0 working fine and I had already flashed an R9 270 2GB which was also working with graphics acceleration. After a couple of boots this way it crashed. Let me know if you have any ideas around that.