Although generally reliable in normal macOS and in Recovery, First Aid sometimes runs into problems with external bootable 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.
Created when you update macOS, its Fallback Recovery OS is made from the previous Recovery OS. Here’s how to check whether it’s available on your M1 Mac.
Apple has revealed the hidden Fallback Recovery OS mode available on M1 Macs. How to enter and use it, and why it’s another big plus.
How you might be able to update an external bootable disk, errors you can encounter, and how can you use 1 True Recovery?
Intel Macs have 14 different startup modes and variations, each engaged using different key combinations. One True Recovery replaces those with a single action and GUI with help. It’s a big step forward.
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.