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macOS Big Sur Does NOT Boot with iMac14,2 System Definition

So if I change my 14,2 configuration to something else, will I have to update my Serial Number too? I seem to remember having to do this in the past and it was rather unpleasant. Also with my processor I am not sure what to change my configuration too. Any suggestions?

Yes, you will have to update your Serial number, other than having to reauthorize software it is not terrible but I do not have a huge amount of software to worry about. 15,1 looks to use a 4th gen CPU.
 
So if I change my 14,2 configuration to something else, will I have to update my Serial Number too? I seem to remember having to do this in the past and it was rather unpleasant. Also with my processor I am not sure what to change my configuration too. Any suggestions?
Logout of iCloud and the Apple Mac App Store. Then, see this Post for the easy way to change your System Definition. :thumbup:
 
That is all fine and well, but when I do this won't I loose my keychain. Is there a way to avoid that?
 
That is all fine and well, but when I do this won't I loose my keychain. Is there a way to avoid that?
Backup your Keychain first to have a second copy.
  • Keychains are usually located in the Keychains folder in the Library folder in your home folder. To locate these files, press and hold the Option key and choose Go > Library, then open the Keychains folder.
  • Select the keychains you want, then press and hold the Option key and drag the selected keychains into another folder to copy them to the folder.
 
Okay, that is good to know. So to restore it after I change my profile, do I just do a keychain import, or do I just overwrite the new keychain file?
 
Hey guys, I'm running the latest Catalina and I have a dual monitor setup using an Nvidia GT-650 graphics card on a Sandy Bridge 2600K on a Gigabyte Z68X board. No other system definition besides 14,2 works with my dual monitor setup.

I've tried the following;

15,1
17,1
19,1
5,1
6,1
13,1
13,2
8,2

If you guys work with dual monitor setups and have a suggestion, I would greatly appreciate it.
Also, I guess this is a clue I need to upgrade my system. lol.
 
If you guys work with dual monitor setups and have a suggestion, I would greatly appreciate it.
Also, I guess this is a clue I need to upgrade my system. lol.
Nothing wrong with staying on Catalina a couple of years and avoiding Big Sur for now. Then build new when you need to upgrade from Catalina. Big Sur is a transitional OS from Intel x86 to Apple Silicon ARM RISC and it's still not ready for everyday use in my opinion.
 
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OK so macOS Big Sur Public Beta is now out, and we just wanted to clarify things a bit regarding system definitions. For years we here at tonymacx86.com have used iMac14,2 as the suggested system definition in MultiBeast- it was a basic trouble free universal default. Starting with macOS Big Sur, Apple has decided to drop support for iMac14,2 systems.

In order to test your system definition, navigate to the upper left corner and choose About This Mac. A window will open showing the booted system definition. If this shows iMac (Late 2013) you will need to change your system definition before installing macOS Big Sur. In fact, you will not be able to download macOS Big Sur until you change it.

Screen Shot 2016-08-30 at 11.05.34 AM.png

This is a pain for real 2013 iMacs, as they now have to trick the OS into supporting their platform. However for CustoMacs running Clover, changing your system definition is very simple.

1. Get the latest version of MultiBeast for Catalina
2. Choose Customise > System Definitions > iMac > iMac19,1
3. Choose Build > Install
4. Reboot system

Please note, OpenCore bootloader has a separate method for adding system definition. You may use a text editor such as ProperTree on config.plist or an app such as OpenCore Configurator.

Hope this helps!
:geek::ugeek::mrgreen:
This is a great bit of info. Thank you Tony. Will an older Z77/87/170 Custom Mac run with these later system definitions?
 
Nothing wrong with staying on Catalina a couple of years and avoiding Big Sur for now. Then build new when you need to upgrade from Catalina. Big Sur is a transitional OS from Intel x86 to Apple Silicon ARM RISC and it's still not ready for everyday use in my opinion.
Yeah, I hear ya! I am experiencing some strange things on Catalina, but not to the point where I just want to go back to Mojave. I just wanted to test it. Eventually, I will want to update my system, but I need to have a dual monitor setup, that's whY I posed the question. Only time will tell. Thanks for the reply.
 
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