How do I enable autologin on TTY running on the Controllers serial port [Raspbian Buster/Bullseye]?
To enable auto logins on the TTY running on any serial port on the Controller log in and run the following commands and reboot.
sudo mkdir -p /etc/systemd/system/serial-getty@ttyS0.service.d/
sudo bash -c "cat > /etc/systemd/system/serial-getty@ttyS0.service.d/autologin.conf << EOF
[Service]
ExecStart=
ExecStart=-/sbin/agetty --autologin pi --noclear %I \$TERM
EOF"
And to disable it run the following command and reboot.
sudo rm -rf /etc/systemd/system/serial-getty@ttyS0.service.d/
When enabling this all users with access to the Controller Pi serial port will be able to log in without any authentication.