Great, now we will have phone "chop" shops springing up all over the place. If I steal someone's phone, all I need to do is immediately turn it off or pull the battery if possible. Then I disassemble, sell the parts, and profit. The kill code did not have a chance to brick the phone. This helps how?
If they do this properly and thoroughly:
- system-level authentication enumerates all authentication keys during the boot sequence on the CPU, camera DSP, RF ICs, display controller, touch controller, etc.'s secure microcontrollers - each component is factory-programmed with authentication keys for all the components the finished device shipped with
- the authentication set is checked to verify that all components are authorized to work together and if they aren't (unauthorized part/repair), the offending parts simply refuse to complete initialization
- when the device eventually gets a chance to phone home, any remaining parts that have also been reported stolen get disabled
- the 'disabled' state may however let some subsystems like GPS and RF operate in limited mode - just enough to report GPS coordinates to authorities
The screen (which is often fused with the front glass and touch sensor) and main PCB are the most valuable parts of a smartphone or tablet so if both of them and most modular stuff containing microcontrollers are kill-switched, the rest of the phone except for the battery is largely worthless even as parts since manufacturer intervention is required to re-program authentication sets after swapping components.