I don't know much about this stuff, but It would seem from what I read, the unique information about a unit is in the hardware and that is what is used for subscription. I just bought a 5504 and replaced the drive with a 160G in less than an hour using the RTVPatch_2.4 utility. I did use the original drive for the copy however.
You may have to re-image your drive. There are a couple of places...
2004-12-16 00:44:00 UTC in ReplayPC
