The finger print sensor would become untrusted in two ways: a. A nefarious foreign government tries to hack into your phone.
The sensor does not make the entry decision. It's just a sensor.
More importantly, Apple has a tool to revalidate a replacement sensor. And if their stores have such a tool, I guarantee you that governments have the same tool

, so if they did come up with a way to get their secret sensor into someone's phone (sounds like an IMF job) they could also revalidate it.
b. A clumsy screen repair. I'd assume case b outnumbers case a by 10,000 to one or more. However, the security guy deciding to brick the phone probably was focused on preventing attacks against the phone's security and never thought of the screen repair case. So the bricking was done intentionally without considering that it was a bad mistake.
Apple says otherwise. They say it was only meant to be a validation check at the factory.
The screen merely relays input while Touch ID directly interacts with the secure enclave in a specialized manner - for all we know, having that route of access with a rogue sensor may allow injection to the SE that allow for some sort of authentication.
On the contrary, we actually know quite a lot about how Touch Id works. Apple detailed it in their public security guide.
The sensor sends the fingerprint info over a serial line to the main processor, which then gives it to the secure enclave to match against stored fingerprint data. There is no "direct interaction" between the sensor and the secure enclave.
Right, but they're suing for killing the phones, not throwing up a warning/error box saying "your phone may be insecure".
They're suing Apple for misleading consumers about their rights, by originally refusing to help anyone who had a third party repair, especially of screens. Here's the Australian press release:
https://www.accc.gov.au/media-relea...misleading-consumer-guarantee-representations
And they already offer a workaround online to reactivate your phone - so it's not an issue anymore.
That's like someone saying they're sorry they stole something, and they won't do it again, so their original theft is not an issue any more. Sorry, but they can still get punished for breaking the law in the first place.
Totally agree! Especially since they've recently updated their repair policy detailing they will in fact fix devices under warranty if third party repairs haven't caused the warranty claim in the first place.
See previous. Most likely Apple will have to man up and pay, with a lesson learned.
While I do agree that's a good thing in general I feel I'm missing something. Are they trying to say all phones should be bug-free from bugs that could render the phone useless even though this get fixed?
They're saying that consumers have certain rights in Australia when something does go wrong.
TL;DR - the Australian lawsuit is not over bricking, but over Apple's initial response to it.