upload sketch via USB->UART converter over RX and TX

hello,
does anybody know how can I upload sketch to arduino DUE via RX0, TX0 ports ?

I have usb uart converter connected to pins rx0 and tx1.
As I read when new sketch is being uploaded ide is trying to send touch message via baud 1200 - and I see that in logs but after that I see message no device found.

Forcing reset using 1200bps open/close on port /dev/ttyUSB0
Waiting for the new upload port...
Uploading .pioenvs/dueUSB/firmware.bin
No device found on ttyUSB0

There is a problem when using the RX0 and TX0 pins bypassing the onboard serial-usb converter.
I am trying to find out why:
https://forum.arduino.cc/index.php?topic=474483.0