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Original poster
Mar 17, 2021
I have an older mac pro desktop that I gave to my son. I think its a 2012 model that I did the OS hack upgrade to I think EL Capitan.

My son was on it and hit the upgrade button not knowing it was a hack and now I just get a black screen of death on it.

It also has an upgraded graphics card so you cant see the boot up screen to start in safe mode. Any help is appreciated.


macrumors regular
Jun 23, 2022
Have you still got an older Mac-compatible graphics card that you can install, to see the boot options?

Might start with that.


macrumors regular
Jun 23, 2022
Yeah, that would work. Are they the same generation of Mac Pro (5,1)?

If not, I was going to suggest using the second Mac to create a USB bootable Mac OS install version with the dosdude1 patch for your hardware. (Search "dosdude1 patch" on this forum.)

You could then remove the drive from the Mac Pro (I think) temporarily and boot to the USB stick. If the USB is the only thing attached, the Mac would automatically default and boot from it.

I think that will allow you to at least get into a recovery mode.

If somebody else is reading this and has a better idea, please chime in!


macrumors P6
Apr 3, 2014
Hong Kong
yes I have another mac pro, i guess I could drop the HD in there and diagnose.
1) Remove the HDD from your son's cMP.

2) Insert that HDD into your own cMP.

3) Install El Capitan (or whatever OS that GPU can work) onto that HDD.

4) re-insert that HDD back into your son's cMP.


macrumors 68020
Dec 27, 2015
If it has a hack to run El Cap it is a MP1.1 or 2.1 about 2006/2007.

guess the update installed a Kernel what has commands in for a newer Xeon generation.

so downgrade the Kernel from your backup, you can do it by mounting the disk in another Mac Pro.
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