How do you write it if it’s readonly? Whether or not the system partition is mou... | Hacker News

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		dcow on Dec 4, 2023 \| parent \| context \| favorite \| on: macOS Sonoma is setting records for update size How do you write it if it’s readonly? Whether or not the system partition is mounted readonly for daily use doesn't have anything to do with the update size.

NikkiA on Dec 4, 2023 [–]

It's protected by T2, the reboot disables the system security protection (SSP) temporarily in the T2, which then allows the OS partition to be written to, then it re-enables SSP and reboots. Only 'special' signed code can enable the update mode.

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