I'm looking into converting my cisco 675 to a 678. I took the 675 apart, but have not got a chance to take a 678 apart. I know of the differences between the two, but can't remember what it is call exactly. I'm not sure if it is a hardware or software issue. My guest is, if it is a software issue, it would have to be the bios chip upgrade. But according to Cisco's website that chip cannot be upgrade nor could the 675 to a 678. I hope Cisco is just pulling our leg to make a buc. Have anyone out there attempt to make the conversion? If so, successful or not, what did u do and how u did it?