Home Forums FineTunedMac Community Lounge First Look At Big Sur

What is already an issue for developers of kernel extensions, is some of the APIs they used were deprecated a couple of years or more back and are totally removed from MacOS 11. Still others, who have relied on embedding their kernel extensions deep in the bowels of the OS, have found installing their extensions breaks the seal on the boot snapshot rendering it un-bootable and they are having to figure a new way to do their job without taking a major performance hit.

artie: Is the system volume actually MORE untouchable in Big Sur than it is in Catalina...?

Mike: Yes, it's cryptographically sealed and then a snapshot is taken. On startup, the snapshot is mounted and that's what the system boots from – the original System volume isn't even mounted. If you mount the System volume and make changes to it, that renders the system non-bootable. You can learn more about it here:

https://developer.apple.com/news/?id=3xpv8r2m

There is actually a mode in which you could modify the system and create your own snapshots, but that's geared towards kernel extension developers.