Apple has released phones with major vulnerabilities hard-coded in the silicon. When the checkra1n jailbreak was released, the only fix was to buy a new phone because it exploited flaws in the bootrom & secure enclave silicon.
(That was in 2020, as of iOS 13 IIRC. It’d be interesting how much of that works against the current iOS 17, and whether Zerodium simply had cashflow issues at the time.)
https://en.wikipedia.org/wiki/IOS_jailbreaking