OpenCore Legacy Patcher boot from External Drive?

[odedia]

I've seen some discussions about this here and there but nothing concrete:
In newer versions of macOS, it seems like Apple is blocking the ability to boot unsigned OSes from external drives (like those created by OpenCore Legacy Patcher).
I've been able to install Catalina on an external SD card on my 2012 Mac Mini since it's the last supported OS, but no later OS appears to be able to boot.
Is there a guide on how to enable external booting with OpenCore legacy patcher? is it even possible anymore?
My internal drive is as slow as hell.

 

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This article is related:

Help! My clone won't boot! | Bombich Software

bombich.com

No Mac will ever boot from an OS that is older than what it shipped with​

 

[odedia]

I got it working eventually - Seems like the only thing that may work is using Apple's own Disk Utility to perform the restore to the external disk, then apply the OpenCore Legacy Patch again.