MP 1,1-5,1 MacPro 3.1 patched to run Mojave, now want back to Snow Leopard

[jngphoto]

I patched my MacPro 3.1 to run Mojave. Now I want to “downgrade” it back to run Snow Leopard.

I have a bootable Snow Leopard drive but it won’t boot into it.

I have a Snow Leopard install flash drive, but installer would not boot.

How to I unpatched or undo my current computer back to stock.

Oh, I remember upgrading the video card from stock.

 

[reader50]

You should be able to boot into Snow Leopard without issue. I suspect the video card is the issue.

What model video card are you using? Snow Leopard requires an Apple-ROM video card. The ability to use PC video cards didn't happen until midway into Mavericks. Also, Mojave wants a Metal-compatible card, and Snow Leopard only has drivers for non-metal cards.

 

[jngphoto]

You should be able to boot into Snow Leopard without issue. I suspect the video card is the issue.

What model video card are you using? Snow Leopard requires an Apple-ROM video card. The ability to use PC video cards didn't happen until midway into Mavericks. Also, Mojave wants a Metal-compatible card, and Snow Leopard only has drivers for non-metal cards.

I think I upgraded to Metal-compatible card. I guess I would need to replaced the original card. Is this my only option?

 

[reader50]

It depends on the details. What exactly are the two video cards? Original and current.

 

[Apple Fan 2008]

I've gotten my 5,1 to run both Monterey and Snow Leopard on different drives, I just had to switch GPUs to get acceleration.

 

[jngphoto]

It depends on the details. What exactly are the two video cards? Original and current.

The original was the one that came with the machine. The current one is metal-compatible that was highly recommended to run Mohave. I don’t have the machine currently in front of me, but I can check tomorrow.