I’ve got a 2020 MacBook Air and it crashed when upgrading from Catalina to Big Sur.
I can’t boot in single-user mode
Cant boot from a USB drive
Can’t even change the settings to allow me to boot from external drive
and when I go to the terminal and try to run “rm /var/db/.applesetupdone” it tells me NO SUCH FILE OR DIRECTORY
MacBook Air (2020 or later)
You have enabled the T-2 Security chip. That's preventing you from running as an external startup disk:
You have enabled the T-2 Security chip. That's preventing you from running as an external startup disk:
Hi ShouldersChestPantsShoes,
As mentioned by a brody, T2-equipped Macs deny booting from external media by default.
Have you tried reinstalling macOS without erasing your data? To do so, hold down Option-Command-R at startup to summon the latest version of Recovery from the Internet. Once you're in macOS Recovery, select Reinstall macOS (or Install macOS) and follow the onscreen instructions.
The T2 Security Chip (which always runs) denies external boot by default. The user must consciously choose to permit external boot in advance in Startup Security Utility before they can boot from external drives.
I wrote this for Catalina, but I imagine it is all still the same with Big Sur, but I never tested it
rm /var/db/.applesetupdone no such file or directory
