Comodo not allow the IP which allow.

When u set allow a host.in firewall. eg. hostname.no-ip.org
Once this host's ip is change.
Firewall possible will not allow the new IP. it will prompt to user. -_- !!
Suspect we not update the IP in time and firewall got the new IP without any rules. then after u update the host's IP. firewall very persistent , and stick to prompt to user.

Allow Ping

To allow ping at comodo firewall, due to it automatic create some of the rules and blocking the ping.
Due to the rules "black all unmatch" at system process (application part)
just add a rules "allow ICMP echo request" at system process (application part) will do.

miui firmware

Yes, confirmed, there is no OFF button when press the power button. (v4.4.25)
and the import of contact, it only able to import vcard. and after import contact, all the row keep show at notification bar, due to  there is a row (probabbly last contact to import) is not done (well, actually it is imported, as i check)

update miui 4.4.25 already have OFF button. red color.