Did you spot the change that didn’t take place as expected in the 15.2 update this week? It marks the end of the Intel era for Macs.
iBoot
How Intel Macs without a T2 chip boot, and how Secure Boot works in those with T2 or Apple silicon chips. How the latter can still enjoy Secure Boot when starting up from an external disk.
Full details of firmware installed by macOS Sequoia on supported Macs, including on remaining Intel model without a T2 chip, T2 and Apple silicon Macs.
This article lists the firmware versions of Macs that have been successfully upgraded to run macOS 14.8.4 Sonoma. […]
Is your Mac likely to receive firmware updates in future? How can you check whether its firmware is up to date? What happens in Sonoma?
Why do macOS updates keep updating firmware? Is it full of bugs or what? And just what does firmware do?
The rules of firmware updating explained, and their consequences for each type of Mac. How to refresh firmware on a T2, and how to downgrade it in an Apple silicon Mac.
Once the kernel takes over from iBoot, there’s a lot of hardware to get running before the SSV can be properly validation, and kernel extensions loaded.
Sometimes known as iBoot1 and iBoot2, they start work with the LocalPolicy for the intended boot volume, validating its vital components.
Understanding each of the four stages in the Secure Booting of an M1 Mac. These are summarised in diagram available here.
The Eclectic Light Company 