If your Raspberry Pi does not fill up your entire monitor screen on NexDock, you may need to disable overscan.

Open a terminal and enter the code below:

sudo raspi-config

When raspi-config loads, choose Advanced Options > Overscan

After that, choose NO when raspi-config ask whether you want to enable compensation for display with overscan.

Choose Ok than Finish to complete your configuration changes.

Reboot your Raspbian to see if your Raspberry Pi fill entire screen of NexDock

NexDock would not work with Pi4 cases that requires power.

If you still get a “low voltage detected” warning without using any case, issue could be related to USB 3.1 cable. To resolve this you can use a 30cm (1 feet) or shorter USB 2.0 cable.

NexDock goes to sleep mode when HDMI signal is not detected. To prevent Pi powering off, you can switch the screensaver to “noblank” mode or switching it off entirely.

Open a terminal and enter the code below:

sudo raspi-config

When raspi-config loads, choose Advanced Options > Audio

Now you are presented with the two modes  as an alternative to the default Auto option. Select a mode, press Enter and press the right arrow key to exit the options list, then select Finish to exit the configuration tool.

Reboot your Raspbian to see if sound works.

In some rare cases, it is necessary to edit config.txt to force HDMI mode. To do that open a terminal and enter the code below:

sudo nano /boot/config.txt

Erase # on the line you see #hdmi_drive=2 and click ctrl+O to save the file and ctrl+X to exit the terminal. Reboot your Raspbian to see if sound works.

If Raspberry Pi 4 is connected to NexDock you can check the battery charge level at anytime by pressing function key and battery icon on the keyboard.

If it’s not  connected, NexDock goes to sleep mode in 300 seconds.

Please note that the new battery is only able to achieve best performance after two or three full charge and discharge cycles.