MAV> link 1 down


Hi, I am trying to run mavproxy whilst SSH into the raspberry pi 4 and keep getting the following error:
Connect /dev/ttyAMA0 source_system=255
Log Directory:
Telemetry log: mav.tlog
Waiting for heartbeat from /dev/ttyAMA0
MAV> link 1 down
I am calling “ --master=/dev/ttyAMA0” command. I have checked multiple times and the connection between the raspberry pi and pixhawk via the GPIO pins are correct but I am unsure if I was meant to change any settings in mission planner before trying to run this command. Any help would be appreciated. Thanks


This is a common problem with newcomers.

Try --master=/dev/ttyAMA0,57600

[note you typed ‘’]

Also try searching the forum for ‘link 1 down’.


Hi, I tried the suggested command and still get the same problem. What causes this problem and are there any settings that I have to adjust on the RPi or Pixhawk that may resolve this issue? Thanks


Hi, I managed to get it to work using the correct baudrate set in mission planner instead of 57600. Thanks


Stef Good to hear. So you used SERIALx_BAUD to set this rate and then connect with the RPi regardless if you connect to MP?

And what baud rate were you using to connect in the first place to MP? I had assumed these radios only work at 57600.


I used 912600, this is from the ardupilot documentation. I am not using any sort or radio transmitter, only command line in my laptop to control the drone.

I am getting a “Need 3D fix” message when I try to arm throttle in the guided mode. Do you have any idea how to resolve this?


I get this whenever the vehicle GPS is blocked by an obstruction. Once it has a clear view after a few minutes it will normally resolve.


Okay thank you, I’ll give it a try.


BTW, you mentioned only using a laptop. What is your plan if you lose connection after the vehicle is in the air and it becomes unstable or a flyaway?


The python script that will be sent to the drone does not need to be connected to the computer to run the code and the script will land the drone after completing the flight or if the battery level is low.


How do you run the script w/o a computer? A phone?


Agreed with @jax200, having multiple methods of controlling the drone is crucial for flyaway failsafes.

10 points @jax200

closed #13