Permitting root logins
The default login program for HVC terminal devices, /bin/login, restricts root logins.
Root logins are allowed only on devices that are listed in /etc/securetty.
To permit root logins on an HVC terminal device add a separate
line that specifies the device node for the device, omitting the leading /dev/.
For example, to include /dev/hvc0 specify hvc0.
For more information, see the securetty man page. For other login programs, see the respective documentation.