FAQs

How to manually switch HDMI 4K resolution

Android System

In addition to adjusting the resolution in Settings -> Display -> HDMI -> Resolution Settings,you can also use the following commands to manually set the 4K resolution, then replug the HDMI cable:

# Set 4k60:
setprop persist.sys.resolution.main 3840x2160@60
# Update sys.display.timeline (add 1 each time) after setting to make the resolution take effect
setprop sys.display.timeline 1

Is there an issue when connecting a national standard headphone to the 3.5mm jack?

Currently, LKD3588 only supports American standard (CTIA) headphones. There is hardware incompatibility with national standard (OMTP) headphones, which may result in the presence of stereo sound in both left and right channels.

What to do if the device is booting abnormally and keeps restarting?

It might be due to insufficient power supply current. Please use a power supply with 12V voltage and 2.5A~3A current.

What are the default username and password?

Ubuntu20.04/Ubuntu22.04 System

  • Username:neardi

  • Password:lindikeji

  • Switch to superuser  sudo -s

Writing tool to write SN, MAC address

Note: If the development board has undergone eMMC erasure, the previously written data will also be cleared.

Windows Method

  • Install RKDevInfoWriteTool

  • In the Settings of RKDevInfoWriteTool, select ”RPMB”

Configure “SN”, “WIFI MAC”, “LAN MAC”, “BT MAC”, etc., in the Settings of RKDevInfoWriteTool as needed

  • Put the development board into loader mode

  • Use RKDevInfoWriteTool for writing or reading operations For specific operations, refer to the 《RKDevInfoWriteTool User Guide》 PDF document in the installation directory of RKDevInfoWriteTool.

In the Ubuntu system, if there is no sound after plugging in headphones, how to deal with it?

Menu -> Multimedia -> PulseAudio VolumeControl -> Configuration -> the working sound card and turn off the other sound card.

How to deal with system lag?

Enable performance mode:

adb shell
su
echo performance | tee $(find /sys/ -name *governor)

Currently, the Linux 4.4 kernel includes the following governors:

  • conservative: Dynamically adjusts frequency based on CPU load, smoothly increasing or decreasing the frequency at a certain ratio.

  • ondemand: Dynamically adjusts frequency based on CPU load, with large frequency adjustment amplitude, can directly adjust to the highest or lowest frequency.

  • interactive: Dynamically adjusts frequency based on CPU load, compared to ondemand, it has a faster response time, more configurable parameters, and is more flexible.

  • userspace: Provides corresponding interfaces for user-space applications to adjust frequency.

  • powersave: Prioritizes power consumption, always sets the frequency to the lowest value.

  • performance: Prioritizes performance, always sets the frequency to the highest value.

How to capture system LOG?

Android System

1、Settings -> About tablet -> Click  Build number 7 times

2、Settings->System->Advanced->Developeroptions -> Android LogSave。After turning on the function, the  /data/vendor/logs  directory will generate a log folder for the corresponding date, which includes system logcat and kernel kmsg.