Disk becomes readonly.
From Wiki of WFilter NG Firewall
1 Reason
Disk readonly is because unexpected power off.
2 Solution
Please follow below steps to fix it:
In "Module"->"Utils"->"command line", execute below three command one by one:
- mount -o remount,ro /dev/root
- e2fsck -y /dev/root
- reboot
After these three commands, disk read only will be fixed.