M1 Macs are different, as they always start booting from their internal SSD. Basic configurations are simple, reliable with well-established disaster recovery methods.
Startup Disk
Full macOS installers come in different presentations according to how they’re obtained. Explained here are what’s in an installer app, and how a bootable installer disk works.
One command in Terminal which instantly disables any support, and why you can’t (yet) boot your M1 Mac in Linux.
My M1 Mac mini was stuck trying to start up. Its power light was on, but there was no video output, and to all intents it was dead.
How boot security has changed in the M1 Mac. What it allows you to do, and how it restores flexibility and versatility of external boot disks.
You may encounter this when trying to boot into Fallback Recovery Mode. Currently it doesn’t appear to be fully functional, and doesn’t help.
Unlike Intel Macs, M1 models always start booting from internal SSD, and can only offer full Recovery from there too. This has benefits, and some drawbacks too.
Detailed account of disk, volume and folder layouts on Big Sur’s boot disks, complete with roadmaps which are downloadable as PDFs.
Diagrams of the layout of volumes on boot disks for macOS 10.13 to 11, covering both Intel and M1 models.
A complete guide to the structure and layout of APFS startup disks from High Sierra to Big Sur (Intel), together with tear-out PDF charts.
The Eclectic Light Company 