x86: Ubuntu 16.04/Ubuntu 18.04

Use the vi editor to open the /etc/default/grub file and add the following information after the GRUB_CMDLINE_LINUX field:
```
consoleblank=600 console=tty0 console=ttyS0,115200
```
Run the following commands to update the configuration:
- Run the stty -F /dev/ttyS0 speed 115200 command to change the baud speed to 115200.
- Run the stty -F /dev/ttyS0 -a command to check whether the baud speed is 115200.
- Run the grub-mkconfig -o /boot/grub/grub.cfg command.
Use the vi editor to open the /etc/rc.local file and add the following content to the file:
```
systemctl stop getty@ttyS0
```
To enable user root to log in to the BMS through a serial port, add ttyS0 to the end of the security configuration file /etc/securetty.
Run the systemctl is-enabled serial-getty@ttyS0 command to check whether serial-getty@ttyS0 is set to automatically start upon system startup.