It implies that the FBI wants Apple to do that.

Tim Cook doesn't offer an opinion about how possible that might be. As a matter of principle, he doesn't believe that Apple should be forced to make the attempt.

That doesn't stop anyone else from doing so, however. And I suppose that the FBI could seek discovery on all requisite information, take depositions, etc, etc. However, I vaguely recall that discovery can't compel production of new work product. But maybe that's just a limitation in civil litigation.

That's a good point. I guess I figured if they simply can't do it why not say "it's impossible by design," rather than argue the principle?

It seems like their stand would be better saved for when a compromise is requested that is actually possible for them implement.

* I guess I figured if they simply can't do it why not say "it's impossible by design," rather than argue the principle?*

Because the larger principle is what's really at play here. Whether Apple can do what the FBI asks, or not, is irrelevant. What is relevant is that what the FBI asks is bad. Even if Apple can unlock this phone because of shortcomings of the 5C (versus later model), it sets a bad precedent for later, especially if Apple truly cannot unlock the 6s and beyond ("you could do it on the 5, why not an iPhone 7?").

I'm no lawyer, but I'm of the opinion that this is a legal crowbar for later cases, and the Feds are using a tragic incident to drum up support ("you don't support terrorists, do you?")

Maybe it's impossible by design in current iPhones. But this is an older one, not so secure.

As Tim Cook says, it would be a bad precedent. And obviously bad PR for Apple to admit vulnerability.

It is, of course, possible; any iPhone can be forced to enter the restore mode or the DFU mode (don't remember which one) and be erased/reflashed via iTunes.

It won't get unlocked by that, because as soon as the new iOS takes over, it will detect the activation lock and require the Apple ID password to be provided. Also, going through iTunes erases all the data.

But presumably a custom DFU update can only replace the OS without replacing the data. The iPhone doesn't try to protect against valid updates, and will happily run anything signed by Apple; the locked/unlocked state is only about the encrypted user data on the device.

Thanks. I was thinking in FDE terms. So maybe what the FBI wants is doable.

This is my question, too. Can iOS updates be applied to a locked phone? Seems like it should be a simple yes/no answer (and I thought the answer was 'no') but I can't find any clarity here or elsewhere.

If you physically have the phone, de-soldering and moving the flash memory to a custom board for modification is an option.

Well, looks like the ask is for a custom DFU tool:

https://www.theiphonewiki.com/wiki/DFU_Mode

The owner is alive, the phone is owned by the government and always has been.