Each attempt takes 80 ms. That's in hardware. There is a separate retry delay that increases exponentially then tops out at 1 hour per unsuccessful attempt. The

Each attempt takes 80 ms. That's in hardware. There is a separate retry delay that increases exponentially then tops out at 1 hour per unsuccessful attempt. The 10-try limit is the number of consecutive unsuccessful attempts before the device erases its stored encryption keys (effectively wiping itself). It seems that the attempt limit at least is not hardcoded and can be updated, as it has been increased in the past by an iOS update. I would suspect the same is true for the attempt retry delay time. Either way, this is only specifically applicable to devices newer than the 5c, which doesn't have a Secure Element (or "Secure Enclave" in Applespeak). In any case, given a software image made to the FBI's specifications, the time to crack a phone depends on the complexity of the user passcode. If the user had a 4-digit numeric PIN it could be cracked in under 15 minutes. On the other hand, with a sufficiently complex passcode the expected time to brute force the device could be literally in the millions of years.