I worked at Motorola's cellular division 20 years ago. I recall a "stop ship" incident when a 911 bug was discovered. That is, we halted the factory and shipments until the bug was fixed and a new software image was available.
The phone's callstack takes a lot of special actions when calling 911, including locking onto any tower even if it is not in the preferred roaming list. As with many exceptional conditions, these code paths are often not as well tested.
The phone's callstack takes a lot of special actions when calling 911, including locking onto any tower even if it is not in the preferred roaming list. As with many exceptional conditions, these code paths are often not as well tested.