Factory reset doesn’t delete persistent app data enabled by app developer [paraphrased]
What about Erase All Content and Settings? You seriously can’t fully erase a second-hand phone you bought?! That’s insane
I can’t see what was posted above anymore, but the DeviceCheck API lets app developers store 2 binary digits (that means 4 different states: 00, 01, 10 or 11) per device on Apple’s servers. So, no, these don’t get erased during a Factory Reset as they’re stored on Apple’s servers. But your phone will.
What’s even worse is that Apple is not fully erasing the phones that they refurbish.
What’s worse than that is that Apple isn’t even deleting the photos that you delete.
What’s worse than that is Apple.
They are fully erasing it. But it’s still the same iPhone. With a device ID that is banned.
