Didn't we learn that not to be the case since presumably the device can still flash a new apple-signed firmware that would override this ?
Anyway, a hypothetical alternative firmware couldn't just magically bypass the encryption. What it could have done, and I think this may only apply to older iPhone models as it's now handled by the Secure Enclave(?), is make it easier to brute-force the pincode (no lockout, less delay).
It also doesn't really matter whether the compromise is a direct key extraction or just defeating the anti-bruteforce protections, the root flaw here is with the phone accepting new privileged software while locked and still retaining its state.
No, but it could presumably brute force the pin (unless the rate limiting is hardware controlled?) or wait until the user enters it, then decrypt everything.
I think this is the case on newer iPhones. But it might be flawed somehow given how Cellebrite were still able to brute-force?
I'm talking about having device data preserved and made accessible, while the device is screen-locked, without having any credentials or the passcode - pick all three.
Local backup key strength depends on the key. iCloud depends on the law.
But if you lose the passcode to your screen-locked or unpowered device any way of getting data (that has not been backed up) out of it, while it's locked or turned off implies a security flaw even if done via a firmware signed by Apple.