Enable multi-display support for Raspberry Pi 4B (RPi4)

In this article, we will guide you on how to enable multi-display support on Android 14 for Raspberry Pi 4.

Steps to enable multi-display support:

  1. Activate Developer options
  2. Enable multi-display support
  3. Reboot device

Multi-Display Mode in Android works differently compared to our regular computer. Android is not designed for several external monitors, so each input device is mapped to a specific monitor without the ability to switch to a different monitor.

To be able to control two displays, we added a USB Port to HDMI port HID/Touch event routing. This means:

  • USB Port 3 is routed to HDMI Port 0, and
  • USB Port 4 is routed to HDMI Port 1.

Warning: The routing also applies to single display usage. Which means, if a HID is connected to USB Port 3 and a single display is connected to HDMI Port 1, instead of HDMI Port 0, all HID events will be dropped. 

Raspberry Pi 4B USB Port placement

Step 1 - How to activate Developer options

To access Developer options on your Android 14 device, follow these steps:

  1. Access the App Drawer on your device by simply swiping up from the bottom of the home screen.
  2. Open Settings.
    emteria Android OS Settings app in App Drawer
  3. Scroll down and select About tablet.
    Select About tablet in Android Settings app
  4. Search for Build number and tap it repeatedly until you see a message confirming that you are now a developer.
    Enable Developer options by tapping Build number
    Enabled Developer options

Once you have enabled Developer options, you can proceed with enabling multi-display support.

Step 2 - How to enable multi-display support

  1. Go into Settings and choose System.
    Go to Systems via Android Settings app
  2. Scroll down and find Developer options.
    Choose Developer options in System
  3. Continue scrolling down until you locate Force desktop mode and toggle it on to activate multi-display support.
    Enable multi-display support via Force desktop mode setting
  4. Enable freeform windows (optional) to open apps in separate windows instead of full-screen mode. This feature is similar to how it works on a PC, giving the flexibility to move the windows around and resize them to a preferred size.
    Enable freeform windows to open apps in windows instead of fullscreen

Note: The changes will be implemented after a device reboot. Reboot the device via the Shutdown app on the device, or send a Group Command via MDM.