ISO 3166-1: https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2

Kernel regulatory domain list: https://kernel.googlesource.com/pub/scm/linux/kernel/git/linville/wireless-regdb/+/master/db.txt


====== how to change / create a regulatory domain support list ======

1.Enable “CFG80211_INTERNAL_REGDB” in the Kernel config

  CFG80211 INTERNAL_REGDB=y

2.Copy regulatory database(db.txt)

download from 
<code>
git://git.kernel.org/pub/scm/linux/kernel/git/sforshee/wireless-regdb.git
</code>
to Kernel path "${Kernel}/net/wireless"

<code>
$ cp db.txt ${Kernel}/net/wireless
</code>

3.Rebuild the Kernel