To boot from an external disk, Apple silicon Macs need them to have an Owner. Here’s how to investigate ownership, and how it works.
Ownership
Assigning ownership to an external bootable disk doesn’t always work in Recovery mode on an M1 Mac. But there’s an easy workaround.
Memory, support for multiple external displays, bootable external disks, macOS updates, kernel panics, more ports, and more choice of macOS to install are on my list.
M1 Macs have an elaborate system of keys and certificates which allow the installation of second operating systems, as well as the primary OS, based on Ownership.
The primary admin account on an M1 Mac is its Owner, responsible for authorising the installation and use of second operating systems. Here’s what can go wrong with Ownership.