Regulatory domain warnings in system log

Warning messages:

cfg80211: Loading compiled-in X.509 certificates for regulatory database
cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
platform regulatory.0 Direct firmware load for regulatory.db failed with error -2
cfg80211: failed to load regulatory.db

The explanation can be found here: https://wiki.archlinux.org/index.php/Network_configuration/Wireless#Respecting_the_regulatory_domain

Summary of steps to resolve the message:

1. Install crda package
2. Reboot to reload cfg80211 module
3. # iw reg set US (or any country code you want)