Downloaded it today, the links were not working, so Sony online tech support gave me the following link:
http://esupport.sony.com/US/perl/swu...mdl=KDL52V5100
CoolOwl's link also works. Maybe they got the download links fixed.
The 4/20/2011 update is for the 52V5100. This is the correct one.
Not sure why they have a second firmware update listed dated 4/22/2011. This is for a 55" set.
Just be sure to follow the instructions posted on the Sony support site to reset HDMI input sources.
Had the TV running all day and not one audio drop out. Finally, looks like Sony stepped up and corrected this issue!!