MP 1,1-5,1 Mac Pro 5,1, sys boot picker not working, WSOD instead

[h8zgray]

Good day all, I am currently running a cMP 5,1 with a MacEFI Radeon Vega, currently running Mojave via onboard SATA. I have a Sonnett MacFive card and two USB 3.0 cards also installed. I have successfully run MACOS Monterrey via OCLP with no problems. I should have stopped while I was ahead as I have been trying to upgrade to MacOS Sonoma with no joy. I use a stock wired keyboard and mouse connected to a nonpowered USB 2.0 hub connected to the native USB 2.0 ports.

In particular, I have lost the ability to invoke the system boot picker / start up volume selector at startup (usually done via holding the Option key) in order to select EFI Boot to bless the OCLP installer for Sonoma. I tried to get to it via stating in recovery, then selecting boot device and holding down option while restarting that did not work.

On boot while holding Option, I an greeted with the white screen of Death and goes no further. I have swapped out the video card for the older Radeon 5700 XT, removed all cards and drives other than the boot USB and have zapped the PROM multiple times with no joy. Wondering if this a BOOT ROM problem, but I would appreciate any assistance anyone is willing to offer, thank you in advance, take care.


-H8zGray

 

[tsialex]

Things that can help you diagnose your hardware:

1. the BR2032 RTC battery voltage is over 3.00V - a spent battery makes the Mac Pro go completely crazy.
2. any Diag LEDs are lit?
3. any CPU tray red LEDs are lit?
4. maybe one of your DIMMs is problematic, try changing the DIMMs, removing all but one and etc.
5. try to run AHT/ASD if you can.

Things that you should know:

1. some PC keyboards do not work with Apple native BootPicker, several MS/Logitech models do not work or work only when cold booting, Microsoft Wired 500/600 series work exactly the latter way.
2. some USB hubs mess up with the Mac Pro POST, try without it.
3. some PCIe cards have OPROMs that block the Apple native BootPicker, maybe is the reason why you don't have it. I remember that someone wrote something about MacFiver having issues with the Apple native BootPicker when combined with other PCIe cards - but since you tried removing all cards and drives and still have the same behaviour, seems you have a different problem, could be something hardware or most probably could be the BootROM.
4. When the NVRAM volume is corrupt and read only, one of the common failure modes is to boot just one disk and nothing else, seems that is the most probable from what you wrote.

If your Mojave disk still boots, try to boot from it and then dump the BootROM, I've sent the instructions by PM.

Another test that you can do - do you have another Mac that you can clean install Mojave from scratch to a spare disk (do not use any disks that still boots with your Mac Pro) and try to see if it boots when all other disks are removed?

 

[h8zgray]

Good afternoon all, I seemingly solved the mysterious loss of system boot picker on my Mac Pro 5,1. Thank you to reader50 and tsialex for their guidance. It turns out that the Sonnet Tech McFiver PCIe NVME SSD card, once installed will apparently disable the system boot picker and if the Option key is held down then you are greeted with a white screen of death (WSOD) instead. Once i removed the card, the boot picker reappeared, though now I will have to find an alternative PCIe SSD card to house my installs. So glad this was finally figured out, best wishes all.