MP 1,1-5,1 GTX 680 boots into black screen on MacOS and MacOS Installer USB

[cheeseisgreater]

I have a Mac Pro 3,1 on which I have recently upgraded to an eVGA GTX 680. My old card was a Radeon HD 5770.
Currently, I have a partition for Windows 10 and another for Catalina. The 5770 was able to load both operating systems without any issues. Before I tried booting in MacOS with the card, I followed dosdude1's guide on flashing my card to obtain the boot screen as per this video:

My card is the EVGA 02G-P4-2682-KR, which is confirmed flashable.

With this flash, I am able to see the boot screen as expected (Apple logo with loading bar), however, immediately after it finishes loading, my monitor goes black as if the computer is in sleep mode. I tried restoring the original vBIOS which only results in a black screen. I can access the bootable drives menu by holding down the option key. I tried booting into the Catalina installer USB and the same problem arrises: Apple logo, then black screen (I tried leaving it for an hour in case it was just slow, but to now avail).

After trying all this, I put back my HD 5770, which continues to boot Windows and Mac normally as it always did. It also boots the USB installer correctly.

The only way I was able to boot in something Mac with my GTX 680 was when I made a High Sierra installer USB (I did not install the OS, however).

In short:

GTX 680: Boots Windows normally, doesn't boot Mac or Mac installer USB.

HD 5770: Boots Windows, Mac and in installer USB normally.

 

[tsialex]

Test your GTX 680 with a clean install of El Capitan, your problem with Catalina it's probably related to the non-METAL GPU patches.

You will find more useful help asking directly on this thread:

macOS 10.15 Catalina on Unsupported Macs

How to update Catalina Machine Support Video Card Support Pre-Metal AMD video cards (Radeon HD 6xxx series and older without acceleration, Radeon HD 4xxx series and older with acceleration.) Pre-Metal Nvidia video cards (GeForce 5xx series and older without acceleration, GeForce 3xx...

forums.macrumors.com

Most people here use unpatched installs with our Mac Pros. Take a look at the Open Core thread and the MP3,1 variants like this one from @Dayo:

MyBootMgr: RefindPlus|OpenCore

section and follow the steps one after the otherThis is a guide to using OpenCore and RefindPlus, to multiboot Classic MacPros (3,1 to 5,1) as well as equivalent Xserve (2,1 and 3,1). It involves booting Mac OS from one or more OpenCore instances chain-loaded from RefindPlus and booting other OS...

forums.macrumors.com

[automerge]1588887481[/automerge]

OpenCore on the Mac Pro

This guide explains how to use the excellent OpenCore boot loader to install, run, and update the latest version of macOS on the MacPro5,1, resulting in a clean, unaltered operating system just like on a supported Mac.

forums.macrumors.com

 

[cheeseisgreater]

Test your GTX 680 with a clean install of El Capitan, your problem with Catalina it's probably related to the non-METAL GPU patches.

You will find more useful help asking directly on this thread:

macOS 10.15 Catalina on Unsupported Macs

How to update Catalina Machine Support Video Card Support Pre-Metal AMD video cards (Radeon HD 6xxx series and older without acceleration, Radeon HD 4xxx series and older with acceleration.) Pre-Metal Nvidia video cards (GeForce 5xx series and older without acceleration, GeForce 3xx...

forums.macrumors.com

Most people here use unpatched installs with our Mac Pros. Take a look at the Open Core thread and the MP3,1 variants like this one from @Dayo:

MyBootMgr: RefindPlus|OpenCore

section and follow the steps one after the otherThis is a guide to using OpenCore and RefindPlus, to multiboot Classic MacPros (3,1 to 5,1) as well as equivalent Xserve (2,1 and 3,1). It involves booting Mac OS from one or more OpenCore instances chain-loaded from RefindPlus and booting other OS...

forums.macrumors.com

[automerge]1588887481[/automerge]

OpenCore on the Mac Pro

This guide explains how to use the excellent OpenCore boot loader to install, run, and update the latest version of macOS on the MacPro5,1, resulting in a clean, unaltered operating system just like on a supported Mac.

forums.macrumors.com

I'm not sure I have the technical knowledge to do this. I followed @Dayo's steps very carefully and I was able to get Refind working, but I have no idea how this helps me.

I installed a copy of Mojave (patched by dosdude) and used my HD 5770 to perform all of Dayo's steps.

Now all I have is a drive with a patched Mojave installation and an empty APFS partition on my SSD where I cannot install unpatched Catalina (it tells me I require a firmware update).

 

[tsialex]

I'm not sure I have the technical knowledge to do this. I followed @Dayo's steps very carefully and I was able to get Refind working, but I have no idea how this helps me.

Now you can boot Legacy/CSM Windows with OpenCore.

I installed a copy of Mojave (patched by dosdude) and used my HD 5770 to perform all of Dayo's steps.

Now all I have is a drive with a patched Mojave installation and an empty APFS partition on my SSD where I cannot install unpatched Catalina (it tells me I require a firmware update).

Learning OpenCore is a little bit overwhelming, sometimes don't make sense at all when we are studying it, but in the end we can get un-patched/un-modified Catalina installs with MP5,1 and almost un-patched/un-modified with MP3,1.

Takes some time to get it going, but it's so easy maintain and have fully working native Software Updates.

Right now you can install High Sierra un-patched and have Software Updates working without changing anything. Mojave and Catalina need adjusts with MP3,1.