Favicon not displaying after upgrade to 3.7.7

I recent upgraded a site (ocortholab.com) from v3.6.4 to v3.7.3. After making a few tweaks, I got everything back to where it was, but the favicon is no longer displaying. I was using my own favicon, which I re-uploaded to the /wp-content/themes/atahualpa/images/favicon folder. Wouldn't display that one. Changed the value in the Add a Favicon setting to point to one of the pre-loaded favicons that come with the theme. No dice. Blanked out that field so it would use the default favicon (new-favicon.ico). Still no dice. So it seems the favicon functionality is completely broken. How to fix it? Thanks.