2013 iMac (14,1) OCLP from Catalina ---> Sequoia : Can't boot into install USB

[John Stephen]

Hello; I have two iMacs; both 2013 and both happily running Sequoia 15.2. So I have some experience in using the Open Core Legacy Patcher. So recently I offered to do this for a friend, also with a 2013 iMac (14,1). However, despite trying for some DAYS, to create the boot disk, the process fails at the last moment of the verification cycle with an error message. So, I created a boot disk on my iMac 27" (14,2) specifying that it was a 14,1 model. the boot disk created without a problem. HOWEVER, ALT-REBOOT on the Catalina iMac fails to show the boot picker ?!

disk util list shows that the EFI partition has been created (220 MB). 
I simply do not know what else to try and why OCLP is not creating the boot disk on the target (Catalina) iMac. Yes the USBs have been swapped and are all quality SAMSUNG S7 SSDs so, this is no, I think, an issue. 

It is so frustrating because, next to this (to be upgraded) iMac is my own 2013 iMac which migrated (admittedly in many stages over the past 3 years) from Catalina right through to Sequoia 15.2 without a hitch. 

(Yes I have tried creating boot disks for Sonama and Ventura button luck there also_

What am I doing wrong please ? 

 

Thanks

 

John

[Cyberdevs]

Hi @John Stephen

Welcome to InsanelyMac.com

 

In my experience, on some 2013 and 2014 iMacs the picker won't show unless you remove the USB disk, do a PRAM reset once or twice while all the USB disks are disconnected, when the system is about to boot up hold down the option key and when the Apple's original boot screen is shown plug the USB disk and see if the Mac recognizes the USB disk.

 

The best way to create the USB installer for any unsupported Mac is to use the latest version of OpenCore Patcher and run in the native macOS like Catalina then you can use the "Create macOS Installer" button in the OCLP GUI and let it create the USB disk for you which will apply the patches for the unsupported Mac as well.

 

You can read these articles and I hope you find them useful:

https://macmeup.com/easily-use-oclp-to-install-macos-on-your-mac/

and 

https://macmeup.com/how-to-install-macos-on-unsupported-hardware/

 

 If you needed any more assistance just mention me here by using @ and my username.

[cousinsfan]

Hi all - I, too have an iMac 2013 and created the Sequoia installer with my Mac Mini.

In the iMac, I can see the USB but when I choose it, I just get a "NOT" symbol (0 with / in it).

 

Any ideas?

 

Thanks,

John

[Cyberdevs]

On 4/1/2025 at 3:49 AM, cousinsfan said:

Hi all - I, too have an iMac 2013 and created the Sequoia installer with my Mac Mini.

In the iMac, I can see the USB but when I choose it, I just get a "NOT" symbol (0 with / in it).

 

Any ideas?

 

Thanks,

John

You need to spoof the SMBIOS to a supported mac model like iMac19,x or iMac20,x and make sure to use the latest version of OpenCore Patcher they've just released OCLP 2.3.0 for macOS Sequoia 15.4

[Consulmac]

i was able to boot from USB only if my external drive was self powered.

 

I tried with 3 different enclosures and only the one with a wall plug would be available from the picker at boot.