[knappster]

Yesterday at the same time started having this issue - low resolution - on all my devices (Sony TV, Shield Pro 19, Shield Cube). Checked ESN and there were a bunch of numbers missing from the end. Filled out the number missing numbers and now all my devices are back 4k DV. Worth checking.

Thanks for the hint. My shield was also missing a large part of the esn. I added it back from the Android app and it's working great again!

How many characters did you have to add? My Firestick 4K has 64 characters at the end that are missing; do I have to write them ALL at the end?

Adding all of the characters through the Netflix addon ESN editor worked for me, too. I found that the full ESN was stored in the settings.xml file, so for my shield I used a mobile phone with the Android X-plore app to open the xml file and copy the string and the Kore app to paste it into the addon ESN editor. That saved me the aggravation of trying to enter it with a remote.