The 8.1 update killed the 2016 Ultra's ability to output DD 5.1 over HDMI.  Here's a link to the thread where Roku acknowledges the bug:
https://forums.roku.com/viewtopic.php?f=28&t=116363

In my setup, I'm still able to transcode to DD 5.1 over optical, but I have no such luck over HDMI.

I've discovered I'm able to get DD 5.1 output when I connect my Ultra 4640 via optical to my Yamaha RX-V371 receiver.  Unfortunately, now I've run into another bug where menu/system sounds are silenced once I've opened an app and started an audio/video feed (Update: It looks like this doesn't happen...

I just encountered this bug when connecting my Roku Ultra 4640R via HDMI to my TV (which only does DD 5.1 passthrough over HDMI to my AV receiver).  I previously had my Ultra connected via HDMI to the AV receiver which caused me to experience the 8.1 sleep bug .  Guess I'll have to live with the sle...

I've found that my Roku Ultra will sleep as expected if I connect the Ultra via HDMI to my TV with the TV then connected via HDMI to my AV receiver.  It wasn't sleeping correctly when I had it connected via HDMI to the AV receiver.  I have a Sony KDL-40NX711 TV and Yamaha RX-V371 receiver. So connec...

This is affecting me too.  Since the 8.1 update, my Roku Ultra 4640R will not remain in sleep mode when the TV is turned off.  However, it does seem to stay in sleep mode as long as the TV's on.

After power cycling, the Ultra is still exhibiting the scrambled graphics and the problem has even spread beyond the app boxes with garbled graphics flashing in all areas of the screen.  I'm guessing the graphics chip is failing so I'm packing it up for return.

What could be causing the home screen app boxes to be scrambled as seen in this photo ?  This started happening the past couple of days.  If I navigate away from the home screen and then go back everything displays ok for a while until the next time it happens.  Nothing outside of the app boxes is a...

I've also experienced the remote disconnecting from my wired Ultra (4640R) overnight for the past three nights.  I have to power cycle the Ultra so the remote will repair.  I did a factory reset today to see if that might help.  Even if the reset seems to help, I'd be afraid the problem would reoccu...