MP 1,1-5,1 MacPro 5,1 would not turn on

[noonereally7]

So, I had bought MacPro 5,1 recently that came with High Sierra. I used OCLP 1.5 and was able to upgrade it to Monterey without any hiccups. It worked fine. Recently, I got the notification about OCLP 2.0 and I updated it (probably the worst mistake :/). When the system restarted, it loaded High Sierra back (since I did not see a boot picker in the start up (however, this was normal with Monterey using OCLP 1.5), I was not able to select the appropriate boot loader). In panic, I tried to do a fresh install of Monterey with OCLP 2.0.0, and then the system would not turn on. The monitor would only blink (usually it stops blinking when its getting video input). Reading through other people's experience, I tried NVRAM reset, which probably make the issue worse. Now the system would chime on start up and eventually turn off in 2-3 minutes. Someone suggested to perform 4 NVRAM resets. I tried it and for once it turned off but after 3-4 h, I powered it up, and I saw the white screen, apple logo with progress bar and back to High Sierra. Now, to get back to Monterey, I believe I should clean up OCLP throughly and do a fresh install (OCLP 1.5 or 2.0.1). Would that work? and what would be the best way to go about it? Also, what cautions should I take before I do anything else. I also wonder what went wrong that the system worked now? I am also worried about going back to condition where it does not turn on (my major concern!) Would appreciate any help.

Here are system's specs:

Thanks

 

[Macschrauber]

One of the steps is to check firmware / NVRAM

You can use the tool in my signature.

 

[noonereally7]

I was able to start it but it said SIP is enabled. I will see if I can turn it off and then run it? Would there be any other way to test NVRAM and firmware without restarting the system? Cuz, again I am worried about it not turning back on.

 

[noonereally7]

Also, I have so many drives rn. I am not sure if that is a good thing. How do I identify if I want to delete some of them? I have mounted EFI to delete OCLP files.

And this is how it shows up on Disk Utility.

 

[krakman]

first of all I would install Mojave. there were a few boot rom updates for the 5.1 in Mojave.

 

[Macschrauber]

I was able to start it but it said SIP is enabled. I will see if I can turn it off and then run it? Would there be any other way to test NVRAM and firmware without restarting the system? Cuz, again I am worried about it not turning back on.

No, not without restarting.

If you don't want to touch your current installation, you can

a) dump the firmware with Linux, for example booting a thumb drive with Linux is an option.
I like GRML. https://github.com/Ausdauersportler/GRML-FLASH
b) physically dump the rom, this needs soldering the firmware chip, what is very advanced
c) Run an old OS, like Mavericks - what has no SIP features.

d) start High Sierra recovery or createinstallmedia thumb drive and at least allow untrusted kext. What is
csrutil enable --without kext

When it comes to weird nvram / firmware operations, the smc battery is always a thing to look at.
Below 3,0 volts it should be replaced, with same BR2032 type. It can be measured built in, plus is top side, chassis of the Mac is minus.