I understand that this problem is not related to armbian.

I tries asking NexDock but they don't know how to make it.

So, I just wonder anybody knows how to let armbian on Rock PI4B work with NexDock 360's keyboard ?
I know when using Raspberry PI, I can add a line 

dtoverlay=dwc2,dr_mode=host

to /boot/config.txt. But when using armbian, there is no config.txt in /boot.

Thanks.

Your issue report is not a valid bug report per the Armbian bug reporting instructions (https://www.armbian.com/bugs).  With limited resources the Armbian project is only able to spend time on issues where all the requested information has been provided and for only the boards/images/software that are supported.  Your report is invalid for one or more of the following reasons (non-exhaustive list):

 

• it is for an unsupported board or image (CSC/EOS/WIP/edge)
• it is for software that is not supported (such as userspace modules installed on top of the core operating system)
• it has been logged in the wrong forum (for example requests for help that are not actual bug reports)
• it lacks requested data (armbianmonitor output)
• it could have been easily solved by a quick search and/or reading documentation

 

Please review what you have submitted and the bug logging instructions (https://www.armbian.com/bugs) and either add the required information or open a new topic in the correct forum (such as Common issues / peer to peer technical support or General chit chat)