After connecting the controller to the Shield via Bluetooth, I am able to navigate the menus with the D-pad. For some reason I wasn’t able to use the controller to use the on-screen keyboard when searching, either using the D-pad or the right touchpad as a mouse. Maybe I am missing something there. I installed the Steam Link app and steam recognizes it as the Steam controller with all the functionality you would expect.

The right trackpad will show a mouse on the screen and clicking the pad will function as selecting what you are hovering over. Left trackpad can scroll. This is with the puck plugged into the shield. I can do some more testing in a few hours.