I discovered that the Tablo app does not respond to the typical "Back" command on the Shield TV. The "Back" button on the Shield's remote does nothing though the "B" button on the Shield game controller does work. Instead of responding to the Android Key Code "KEYCODE_BUTTON_B" the Tablo should respond to "KEYCODE_BACK" which equates to "ESC" on a keyboard or HID code 0x07 0x0029. I've notified the Tablo company but does anyone have a workaround in the meantime? The family is not keen on having to use a game controller to watch television.
I should have mentioned... In addition to the Shield's remote I am using a Flirc with a Harmony 650 but have yet to find the proper Flirc code to represent the "KEYCODE_BUTTON_B".