Unable to connect to Rock PI 4b+ through OTG

#1

I am unable to connect to Rock Pi 4B+ through adb. The device isn’t showing in “adb devices”
I have tried flipping the hardware OTG switch to both sides, seems no effect, netier sides affect the symtom.

OS: Android 9 and Android 11
USB Cable: USB Cable A to A
Host OS: Ubuntu 20.04
ADB Version: 33.0.2-8557947

#2

On host PC, run sudo dmesg -c

On ROCK Pi 4, put the switch in device mode, and then plug the USB A to A cable to PC

run sudo dmesg -c again, is there any output?

#3

no, there isn’t any output

#4

Do you have serial console access? Or maybe you can install a terminal app:

  echo -n "peripheral" | tee /sys/bus/platform/drivers/rockchip-usb2phy/ff770000.syscon\:usb2-phy\@e450/otg_mode

and then connect to PC, check the sudo dmesg -c

If this doesn’t work, maybe you should check your USB2.0 A to A cable. If on PC, don’t use the front USB ports. If on laptop, try the USB ports on the other side.