Hi @hikaru
I use Tinker2S version 2.0.0-20210413
CONFIG_USB_SERIAL_CH341=y
Actually insert CH340 USBtoUART
linaro@linaro-alip:~$ ls -al /dev/ttyUSB0
crw-rw---- 1 root dialout 188, 0 Dec ?8 04:04 /dev/ttyUSB0
If you have any questions, Please provide dmesg kernel log information.
Thanks