Someone has probably suggested this at this point, but would it be possible for Apple to just unlock the phone themselves without releasing the tools they use to do so?
That's what the FBI is asking, a device to insert an update so that the phone can be hacked by brute force, it's only a 9 number combination. But if they do that then China, Russia, Saudi Arabia, Turkey, India, Pakistan etc kan ask the same and Apple can't say no to that.
This is in effect a backdoor, at first only in the hands of Apple but the same court can then demand that the FBI get's this ability. If Apple creates this there is no way to stop the FBI from getting it.