System updates gets exception even after reboot

Ok. Without any modifications,

chkconfig --list | grep -i dahdi gives the following:

[root@freepbx ~]# chkconfig --list | grep -i dahdi

Note: This output shows SysV services only and does not include native
      systemd services. SysV configuration data might be overridden by native
      systemd configuration.

      If you want to list systemd services use 'systemctl list-unit-files'.
      To see services enabled on particular target use
      'systemctl list-dependencies [target]'.

[root@freepbx ~]#

and chkconfig --list | grep -i wanrouter gives the following:

[root@freepbx ~]# chkconfig --list | grep -i wanrouter

Note: This output shows SysV services only and does not include native
      systemd services. SysV configuration data might be overridden by native
      systemd configuration.

      If you want to list systemd services use 'systemctl list-unit-files'.
      To see services enabled on particular target use
      'systemctl list-dependencies [target]'.

wanrouter       0:off   1:off   2:on    3:on    4:on    5:on    6:off
[root@freepbx ~]#

Does that look right?

Well, that worked! With all the latest drivers installed, DAHDi started up perfectly on reboot.