I find it hard to believe that the FBI cannot crack an iPhone. After ten attempts the phone might wipe itself, which is what the FBI is afraid might happen. Maybe they do not use Macs in the FBI, but with Xcode, a tool from Apple to create code for OS X and the i devices, it is possible to emulate Apple devices. So how could an iPhone be emulated? Easy! Dump the memory from the phone. I used to do this with Atari 2600 cartridges in the 1970s. While the method is different today, the basics are the same. Afterwards, import the image to a Mac and try until cracked. Copying the ROMS and flash should work on any device. It may take longer without the ten try limit as the emulated image might wipe itself, but it gives the FBI a chance to crack the phone. They could have multiple instances running at different points to try to crack it. Given the proper resource, it should take less than one hour to break. Does the FBI pay well?