Inability to boot exclusively off an external hard drive for one. https://eclecticlight.co/2021/02/10/external-boot-disks-still-dont-work-properly-with-m1-macs

Inability to boot exclusively off an external hard drive for one. https://eclecticlight.co/2021/02/10/external-boot-disks-still-dont-work-properly-with-m1-macs/ https://eclecticlight.co/2021/02/10/external-boot-disks-stil... , https://tidbits.com/2021/05/27/an-m1-mac-cant-boot-from-an-external-drive-if-its-internal-drive-is-dead/ https://tidbits.com/2021/05/27/an-m1-mac-cant-boot-from-an-e... This is a very common thing that all PCs can do and you'd expect a top end ($$$$) laptop to be able to do. But because of proprietary choices in the boot process M1 consoles can't.