DId you reboot? I had an issue with one Mini after the update. For some reason it got stuck in pcm mode and would not send DD audio. So for me I was gettting TiVo sounds when normally I should never hear TiVos sounds when watching content on FiOS. Since every channel on FiOS uses Dolby Digital. Once I rebooted it was fine.
TiVo Mini x4
Roamio Basic OTA
53TB unRAID2--36TB unRAID3--32TB unRAID1a