The 79 is different to the rest of the Hitachi drives, basically because it has a bit removed. That 'bit' is the hardware required to dump/flash the drive.
The passkey is basically that bit, with the commands for flashing the drive. Meaning without the passkey installed (which is not an easy thing to do at all), you ain't getting shit from it
If you look hard enough you'll be able to find people that do it. But there aren't hundreds that advertise....