When my 2010 Mini arrived, I cloned my boot disk from my '09 Mini, and started from that. Everything worked perfectly, except the Ethernet. Network prefs wouldn't even detect the cable plugged in, when it worked perfectly on my '09, and my G3 Powerbook. I found a thread on the support.apple forums that the 2010 Mini ships with a specific build of OS X that is the only way to have the ethernet function. I re-installed SL from the '10's factory restore disk, and the Ethernet worked. Using Apps/Utilities/Migration Assistant after the fact was as thorough and smooth as I was always afraid it wouldn't. Just thought I'd share, because I spent many hours doing every reset, every standard troubleshoot, before discovering the answer.