Nvidia has released firmware version 1.3 for its Shield Android TV set-top box. The update is meant to fix issues with Wi-Fi connectivity and connectivity with the Shield wireless controller. It also adds support for newly released apps and games, including Half-Life 2: Episode 2.
Still missing from this update is a workaround to allow read and write access to microSD cards. According to a post by Nvidia support on the Shield forums, Android TV is missing a component that allows applications to have read and write access to the entire card, and that bug is slated to be fixed in a firmware update at some point. I've attempted to write to a card using firmware 1.3 on my personal Shield Android TV box, and the issue doesn't appear to be resolved this time around.
Update 8:05PM: Nvidia has informed us that the SD card issue will be fixed with the next over-the-air (OTA) update.