Catalina compatibility...Old guard? Help Please!

[RandomNumber]

Hi Arim713. Thank you for the question, I was hoping to get other folks with these Legacy systems to weigh in on their continued use with Catalina. I will try to answer your question but first I want to mention that I am waiting for a response from Going Bald which might contain a link to a more systematic method for getting Catalina installed and working on X58 systems. As to how I accomplished it, I'm not sure I can answer that with complete assurance. I tried so many methods to try and accomplish it and now that I've succeeded I can't remember for certain which method worked. I think the successful attempt involved:

1. Cloning my existing Mojave to a separate SSD.
2. Boot into that clone using SMBIOS for imac 14,2. (I used my reliable Clover config.plist but just changed from MacPro 5,1 to imac 14,2).
3. Update that Mojave install using software update to Catalina (still with imac 14,2 SMBIOS).
4. Apply the boot argument "-no_compat_check" (without quotes)
5. As I recall once I did this and booted into Catalina with SMBIOS imac 14,2 I next switched back to my original Clover config.plist (added same "-no_compat_check" boot argument in clover) and the system booted.

My hardware is as listed in my signature Build #1. I hope I have remembered correctly and this helps. Maybe Going Bald will add the link he mentioned above and that will further clarify.

 

[Arim713]

by the way I read that when you change from mac pro to imac you reduced the multiplier of the cpu, then you can not overclock in MacOS ?, I thought to try to put the x5675 to 4GHZ to try to scratch some more fps in MacOS games and reduce the times of imovie export, although I don't think an x5675 without overclock is a bad machine

 

[RandomNumber]

by the way I read that when you change from mac pro to imac you reduced the multiplier of the cpu, then you can not overclock in MacOS ?, I thought to try to put the x5675 to 4GHZ to try to scratch some more fps in MacOS games and reduce the times of imovie export, although I don't think an x5675 without overclock is a bad machine

That was my experience and the very reason I wanted to go back to my Mac Pro SMBIOS. I suspect there might be a way to adjust the imac 14,2 SMBIOS to have the higher multiplier needed for a proper overclock but I was stuck with a max 12x top speedstep as indicated by HWMonitor. It was easier for me to use my now functioning Mac Pro 5,1. With Mac Pro 5,1 and my Xeon X5650 I can achieve a stable overclock at 181 bass clock with 22x multiplier for 3.98 Ghz. I can actually get 4.07 Ghz but it is slightly unstable so I settled on a perfectly stable 3.98.

 

[Going Bald]

My hardware is as listed in my signature Build #1. I hope I have remembered correctly and this helps. Maybe Going Bald will add the link he mentioned above and that will further clarify.

Never got an answer if I could link, so I will give you a hint - dosdude1.com. This is a site run by a Mac owner for Mac owners. Click on My Sofware tab - self explanatory for what you see.
Install Clover to installer USB, use Clover Configurator to add NVRAM boot-arg -no_compat_check and you are good to go.

 

[RandomNumber]

Never got an answer if I could link, so I will give you a hint - dosdude1.com. This is a site run by a Mac owner for Mac owners. Click on My Sofware tab - self explanatory for what you see.
Install Clover to installer USB, use Clover Configurator to add NVRAM boot-arg -no_compat_check and you are good to go.

Ahhh yes. I am familiar and in fact it was one of the things I initially tried. I emailed ddude first to ask if it might work and at the time he felt confident it would. As I mentioned above I tried so many things I'm not positive what series of things actually resulted in a working system (not a very scientific approach) . In any event, I appreciate your taking time to guide us.

 

[RandomNumber]

Anyone have any thoughts on updating this Legacy system (running MacPro 5,1 SMBIOS) from 10.15.1 to 10.15.2? Which is the preferred method, stand alone combo update or software update? Anyone know if trying this interim update will render the unit once again "unsupported" causing me to start once again the entire process from the very beginning? Your thoughts or experience is appreciated.

 

[Going Bald]

Anyone have any thoughts on updating this Legacy system (running MacPro 5,1 SMBIOS) from 10.15.1 to 10.15.2? Which is the preferred method, stand alone combo update or software update? Anyone know if trying this interim update will render the unit once again "unsupported" causing me to start once again the entire process from the very beginning? Your thoughts or experience is appreciated.

I used software update and had no problems. Currently running the latest 10.15.2

 

[RandomNumber]

I used software update and had no problems. Currently running the latest 10.15.2

I must have used a different technique to install 10.15 because my 10.15.1 did not get an update to 10.15.2 through software update. In fact trying to use the free standing MacOS 10.15.2 updater I was presented with the message that my machine was unsupported for Catalina. I think I probably originally installed Catalina by using SMBIOS 14,2. I did get the update applied by again booting with 14,2 SMBIOS and completing the update that way. Then I switched back to MacPro 5,1. Seems to work fine so far. At some point I might want to give the patcher method a try though as it allows for updates using software updater and also provides the message that the update is available.

I've been using this rig since 2010 and it has been great! I'm not ready to move on just yet!

 

[Going Bald]

I must have used a different technique to install 10.15 because my 10.15.1 did not get an update to 10.15.2 through software update. In fact trying to use the free standing MacOS 10.15.2 updater I was presented with the message that my machine was unsupported for Catalina. I think I probably originally installed Catalina by using SMBIOS 14,2. I did get the update applied by again booting with 14,2 SMBIOS and completing the update that way. Then I switched back to MacPro 5,1. Seems to work fine so far. At some point I might want to give the patcher method a try though as it allows for updates using software updater and also provides the message that the update is available.

I've been using this rig since 2010 and it has been great! I'm not ready to move on just yet!

In Clover configurator / NVRAM add boot argument -no_compat_check

 

[RandomNumber]

In Clover configurator / NVRAM add boot argument -no_compat_check

View attachment 443047

Even after adding the -no_compat_check boot argument I get the apple message "This software is not supported on your system." Any ideas? Just trying to update to 10.15.3 from 10.15.2. Software update doesn't show any updates and trying combo update results in the software unsupported message. ???