Installing Ubuntu Server 18.04 LTS and ROS Melodic with MAVROS on Raspberry Pi 4

Helpful links
https://ubuntu.com/download/raspberry-pi
http://wiki.ros.org/melodic/Installation/Ubuntu

1. Download image and burn to SD card with Etcher

2. The first challenge on boot of Pi is setting up the wireless network. This will require a keyboard and ethernet connection to Pi. I've documented a bit in this gist:
https://gist.github.com/dbaldwin/fa1baac11b0ae2f000092b695c3d0b33

3. After getting the network setup you'll want to SSH into the Pi. At least that's what I did.

4. Now logged into Pi I used the following commands to get ROS Melodic installed:

sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'

sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654

sudo apt update

sudo apt install ros-melodic-ros-base

echo "source /opt/ros/melodic/setup.bash" >> ~/.bashrc

source ~/.bashrc

5. Install MAVROS

sudo apt-get install ros-melodic-mavros ros-melodic-mavros-extras

6. Install Geographic datasets
wget https://raw.githubusercontent.com/mavlink/mavros/master/mavros/scripts/install_geographiclib_datasets.sh
chmod a+x install_geographiclib_datasets.sh
sudo ./install_geographiclib_datasets.sh

7. Connect to Pixhawk
Plug pixhawk serial port into RPi 4 USB

8. Launch MAVROS and see Pixhawk telemetry!
roslaunch mavros px4.launch

9. There may be a permissions issue with the serial port. Make sure the user launching mavros is in the "dialout" group.
sudo usermod -a -G dialout db
(db is the user in this case)

Are you able to autostart this even with serial issues?