I have the M1001 SB. It was running the beta 2.7.78 with WPA enabled. It registers to the AP just fine and finds the network and views the files in my computer. However when I plan some songs or access Internet Radio, the device does either of two things: 1) It reboots 2) It Freezes Up. I decided to boot in safe mode and updated the firmware. It downloaded and upgraded just fine although it seems the latest version is still 2.7.78. I noticed that while connected to the ethernet cable all seems well and the unit does not freeze-up. However, even with the latest upgrade the unit continues to freeze-up while on wireless. At one point I thought it might be the music server and so I changed from MS Windows Media Player to Firefly but it did not help. I have the following configuration:
M1001 (2.7.78)
ACTIONTEC wireless router (Verizon FIOS provided)
802.11 B WPA enabled
Windows XP Professional workstation
Firefly server