The Nvidia Shield TV started receiving Android 9.0 Pie yesterday, making it the device's fourth major software update. That being said, you may want to hold off on upgrading if you use your Shield TV as a DVR for HDHomeRun, as it seems to have broken this functionality — though a fix is being worked on.

WARNING: Please do not update to Android 9 on your NVIDIA Shield if you are using it as an HDHomeRun DVR. It appears the update causes problems. We'll inform you when we have a fix — Silicondust USA, Inc (@HDHomeRun_US) August 1, 2019

The issue, which has to do with accessing saved videos in the DVR, was first spotted by Silicondust forum members — a Wally McCarthy even demonstrated this in a video. The running theory is that the problem seems to be related to the system resetting the Location Services permission. This doesn't stop the HDHomeRun app from working on Shield TVs though, so as long as you don't need to play recorded videos you should be okay. Alternatively, if you run a Plex server on the Shield TV, you could always use that to record live TV instead, though this does require a Plex Pass.

The good news is Silicondust is being proactive about the issue and says fixing it is a top priority, so you should expect a solution soon.