No communication on linux UPDI with attiny 1616

[skorakora]

Completely no communication
I have tried to eliminate everything.
There is only short LOW pulse sent that lasts arround 90us
It repeats 3 times.
My command is: "pymcuprog ping -d attiny1616 -t uart -u /dev/ttyUSB0"
response is:
"
Connecting to SerialUPDI
pymcuprog.pymcuprog - ERROR - Operation failed with PymcuprogError: UPDI initialisation failed
"

Problem is definitely on side of library, I read trough documentation, and this impulse will never initiate communication. uC is waiting for special sync character. This pulse is not even close to the sync character labeled in datasheet.