Nvidia Shield play with the X-Arcade

The Nvidia Shield is an Android based console with its own store of streaming games, and it also offers Steam game streaming. But it's also a popular emulation device which can be loaded with RetroArch to play all of the classic arcade and console games that RetroArch emulates, which is a lot!
The X-Arcade works as a keyboard in mode 1 for games that support keyboards for play, but most games will expect an Xinput device. X-Arcades with our Tri-Mode PCB works on the Nvidia Shield in mode 4 (Xinput mode), and the menus and games will mostly expect the X-Arcade to be in Analog 1 mode.
Tri-Mode PCB notes (not original Arcade2TV-XR mode instructions):
- Your Shield must have firmware 7.2.3 or higher.
- X-Arcade must be in mode 4 (Xinput mode).
- Use Analog 1 mode (PM + Y) to navigate RetroArch menus and play most games.
- Mode 3 works in menus only, not in games.

Source article: <https://support.xgaming.com/support/solutions/articles/12000055737-nvidia-shield-play-with-the-x-arcade>
Original Arcade2TV-XR: use its own XInput profile
Support explicitly confirmed that the original Arcade2TV-XR can work with NVIDIA Shield TV when set to XInput. This is a staff product clarification; the source customer did not report a completed connection or gameplay test. It does not establish every game's controls, trackball support, an adapter requirement or a specific wireless path.
The Mode 4 and PM + Y instructions above describe a legacy controller fitted with a Tri-Mode PCB. Do not transfer those mode numbers or button combinations to original XR, XR MAX or another board. Identify the exact controller, select its documented XInput profile, test joystick/buttons at the host, then assign them in the intended Shield game or emulator. A working menu is not proof that every game function works. If input is missing, send support the controller/dongle identification, actual connection, mode and host-versus-game results before buying adapters or changing firmware.