IIRC, didn't the unlock in the San Bernardino case use an exploit(s) specific to the 5C or something? Also IIRC the iPhone 6 has some sort of hardware-level protection against this.
Anything you may have heard is almost certainly speculation. It seems pretty likely that a particular Israeli company supplied the FBI with an exploit, but no one has said anything about that exploit being specific to the 5c.
Even Apple does not seem to know what the exploit was, as they are pursuing legal options (or dropping hints to that effect) to compel the FBI to reveal it to them.
Even Apple does not seem to know what the exploit was, as they are pursuing legal options (or dropping hints to that effect) to compel the FBI to reveal it to them.