What is TrustZone being used for in practice?
If it's present, this is used by apps like 'Google Authenticator' and 'Symantec Vip access' to store credentials in such a way that they can't be copied off the device or backed up.
When this technology works perfectly, the idea is if you have a short passcode and someone steals your phone, they can't extract the encrypted data and brute-force the passcode without an electron microscope and a team of engineers.
Unfortunately, it can also be used for user-hostile applications like providing DRM and preventing backups and rooting.
I was wrong about Google Authenticator. I assumed it was the same as Symantec because of all the people online complaining about being unable to back up their credentials.
iPhones don't use it. They don't use Qualcomm SOC's.
(But yes, he is a troll and this whole case has nothing to do with Apple).
nah
TrustZone is an ARM thing, and the iPhone Secure Enclave is indeed built on TrustZone.
Apple do not use Qualcomm and this a Qualcomm-specific bug. But Apple do use their own modded TrustZone.
Despite widespread rumour to the contrary, the secure enclave on iPhones is a separate core, not just TrustZone on the main CPU.