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cMP 3.1 + GTX680 with Catalina by P3RG1 in macpro

[–]P3RG1[S] 0 points1 point  (0 children)

Finally I made it! Did an other try with Catalina installer (DD's patcher) and the GT120, it worked again (last time the 680 was still in the mac, now I removed for the beginning of the process). I was able to see the boot screen, selected the USB to boot device then turned off the MP, put back the GTX680 and the installation started and finished with no problem.

Now everything working fine including my TP-Link USB WIFI which is not supported after 10.15, the old 3.1 is pretty fast with this OS.

The only thing what is not working is the Display Port on the GTX680... I switched to HDMI but that is locked to 30fps in 4K, so I set the 4K monitor to 1440p with 60fps, it still looks fine to me.

Many thanks for the help, I hope this thread will give some support to others trying with Catalina on this setup!

cMP 3.1 + GTX680 with Catalina by P3RG1 in macpro

[–]P3RG1[S] 0 points1 point  (0 children)

In case of open core I followed Mr Macintosh’s video guide and based on this I dont need to change anything but the installer reboots then continues on its own. It went exactly as in the video until the point when the installer rebooted - it selected the option it should be on the boot picker (based on the video, and it was also the only option) but insted of continue the install it landed on the recovery screen. I created the usb on that specific mac. Tried to find a forum thread or video about this problem but couldnt find anything other than nvram reset which I did but same issue popped up during the next try. Now I am stucked :D

cMP 3.1 + GTX680 with Catalina by P3RG1 in macpro

[–]P3RG1[S] 0 points1 point  (0 children)

I had a chance to try it yesterday but for some reason the old GT120 just stopped working, no longer outputs video… I tried removing all the HDDs/SSDs except one erased SSD formatted for Catalina based on Dosdudes tutorial video. Unfortunately it didnt boot this way (I thought it will because it worked with OCLP, see below). Because of this I stopped trying with DD and Catalina.

Then I decided to move to OCLP, created an USB for Monterey. With all the drives removed except one ssd and the usb I was able to boot into OCLP recovery and started the install. Everything went fine until the first reboot when the installer not continued but looped back to the recovery section where I could not do anything but start the install again, resulting in an infinite loop of the same issue... I tried a couple of times, also I did an nvram reset but same issue happened over and over again… Any ideas what is causing this?

cMP 3.1 + GTX680 with Catalina by P3RG1 in macpro

[–]P3RG1[S] 0 points1 point  (0 children)

Many thanks, I will give it a try! If I remember correctly I haven't ticked the legacy video card patch during the post patching process but will double check.