My original 6416 FIOS HD DVR settop box has been replaced with a newer 6416-2 HD DVR. I have noticed watching Formula 1 on Speed (Non-HD) that the 4:3 SD picture is now overscanned on my 4:3 Sony HD capable TV -- the lap counter at the top of the picture is now cut off, so is info at the sides and bottom. The overscan is consistent on all sides.

I spoke with FIOS but even their 2nd level tech did not know how to access the diagnostic menu or service menu on this unit. They have apparently made a change where the previous method just puts the box in standby mode.

SD Override and Video Format are now available from the user menu but no combination of these settings solves the problem.

Any ideas? Or pehaps a solution for accessing the other service menu options on a 6416-2?

Thanks!

STB's do not overscan their outputs. Most HDTVs normally overscan their inputs over Component or DVI/HDMI, only the latest models have an option to disable the overscan. I have a 6416-2 and there is no setting avaialble that I am aware of to underscan the output.
Have you tried using the VGA output from your 6416-2 if your TV supports a VGA input?