Sorry, I'm not sure I understand - can you explain more? How does the OS making it unmountable when it's locked stop the FBI from physically removing the internal storage and looking at its contents via another device? I can see how it might require specialized forensics equipment depending on how obscure/proprietary the internal storage hardware is, but that seems like something the FBI would have access to or be able to obtain...
I would imagine that busting a pimp isn't exactly high up there on the FBI's list of priorities, at least not high enough to desolder a NAND chip (possibly destroying evidence) and reverse-engineer its raw access protocol. Far simpler to just make Google give them the password.
