MAV> link 1 down

Hi, i’ve been trying to connect a pixhawk cube black to a RPI4B . i did all the steps on mavling documentation already 3 times as i am really fresh on raspberry .
changed the serial port as said, added the line droverlay=disable-bt on boot config. after the MAV> link 1 down i can switch flighht modes but have no return. rebuilt the cable 2 times already…
Any sollutions?

trac@raspberrypi:~ $ mavproxy.py --master=/dev/ttyAMA0
WARNING: You should uninstall ModemManager as it conflicts with APM and Pixhawk
Connect /dev/ttyAMA0 source_system=255
Log Directory:
Telemetry log: mav.tlog
Waiting for heartbeat from /dev/ttyAMA0
MAV> link 1 down
MANUAL

Cheers

EDIT
i “purged” modemmanager as shown on the message above. now;
Connect /dev/serial0 source_system=255
Log Directory:
Telemetry log: mav.tlog
Waiting for heartbeat from /dev/serial0
MAV> link 1 down

Hi there, have you been able to solve the problem? Because I am having the same problem.

hi there. yes, i think i damaged the uart port on the raspberry pi so i changed the connection to usb.
simply connect the 2 usbs’s ans switch the ttyAMA0 to ttyUSB0( i am not sure of this port, but you can get the list of tty’s forget about the tty(nr) and try the ones that are not numbers… if i have time tomorrow i will connect the system to my pc again and sort it out.