[arayh]

It exploits the bootrom, which is by definition unpatchable.

[uxp100]

I suspect Apple has ways from the factory to fix this. Secure Fuses that can disable code paths, or inject code. But unpatchable in the field.

[xurias]

Future devices can be fixed at the factory. That still leaves tens of millions of vulnerable devices which are, as repeated before, unpatchable.

[saagarjha]

In the factory, Apple can just create new hardware without this flaw.

[uxp100]

That would be in the fab, not the factory, might mean tossing out inventory, and will take longer. I'm guessing they will do both.