Hey Everyone,
Just for kicks I put my S2 SA HD (monte 120gb) in a DSR7000. To my surprise, the system boots fine. It even sees the SAT tuners and tries to acquire guide data. It cannot get model id, but shows rcvr id.

The SA has 4.0 with HMO.

It plays recordings! HMO shows de-active, though it is listed in system info and on the SA I have it enabled. Service also shows as inactive but I assume this is because of the 'tivo tier'

USB Ethernet works. Telnet hacks work.

Interesting thing is, could it be that 4.0 has cross-compatibility or something built in for the future? Generally I would think this not to work.

Looks like there are some fun possibilities here...