After the FBI received help from a private party in unlocking the iPhone 5c used by a San Bernardino shooter, Apple sought an answer to what method had been used to break open the iPhone. Earlier, before the battle between the FBI and Apple came to a standstill, several analysts had suggested that the methods that may be used to unlock iPhone 5c would possibly not work with latest iPhones that have the Secure Enclave.

FBI's director James Comey has now confirmed to the CNN that the "tool" indeed doesn't work with the latest iPhones.
The FBI director also said the purchased tool worked only on a “narrow slice of phones” that does not include the newest Apple models, or the 5S.
As speculations ran amok about the private party that has helped the agency in unlocking the iPhone, Comey said he has "a high degree of confidence that they are very good at protecting it, and their motivations align with" the FBI.
When asked if the agency will share the details of the loophole that was used to break open the iPhone 5c, Comey said that the government was considering whether to tell Apple.
"We tell Apple, then they're going to fix it, then we're back where we started from," he said. "We may end up there, we just haven't decided yet."
While the director didn't share the details of the hack that was used to open the iPhone 5c, it did say that the method only works with a "narrow slice" of iPhones. This lends some confirmation to earlier reports where Edward Snowden and other analysts had said that the FBI could use the mirroring technique to bypass the lockscreen restrictions. In this method, auto-erase function that erases the contents of an iPhone after a few login attempts can be bypassed by resetting the counter and repeatedly copying the contents of the flash memory. This method, however, doesn't work with the phones that have the Secure Enclave as SE also registers login attempts, making over-writing the flash memory useless.
A legislation is still in consideration that would force tech companies to cooperate with the law enforcement agencies to bypass encryption. Apple, several other tech companies, and privacy activists have vocally fought against the idea of any such legislation that compels the tech leaders into creating loopholes in their own services and products, opening them to misuse by criminal hackers and authoritarian regimes.