Hello,
it comes from : Tinker Board 2 & 2S · TinkerBoard/TinkerBoard Wiki · GitHub
this is what I have done: ( it's written in that wiki)
1.On the Tinker Board 2S Debian system, edit the source.list file to add the PPA URL for
Tinker Board 2S as the following
sudo vim /etc/apt/sources.list
deb http://ppa.launchpad.net/asus-iot/test-tb2/ubuntu focal main
2.Using the following commands to update and install the general version. It will install
the latest tinkerboard2S kernel image and headers
sudo apt-get update
sudo apt install uboot-tinkerboard2
sudo apt-get install linux-headers-5.10.198-tinkerboard2
sudo apt-get install linux-image-5.10.198-tinkerboard2
sudo reboot
And so after reboot nothing start.