I'm now having the same problem you described....did you find a solution? I tired upgrading the software but it doesn't find the usb connection.
After switching to the newer available firmware version in the DTV menu, my monitor keeps restarting while in this mode (believe me, the startup/shutdown musical tune quickly gets annoying). The other modes (dvi, analog tv, hdmi) work fine as long as i manage to switch to one of these modes in time before dtv restarts.
Searching the net learns me I am definitely not the only one with this problem, and the most suggested fix method is return to samsung.
Surely a simple software issue should be possible to fix without the need to return my main computer monitor, I already tried to perform factory reset but it didn't solve the problem.
Isn't it possible to get this fixed with a software patch or through one of the options in the service menu? I'd hate to have to go through the procedure of sending the product back without a replacement monitor.