[Q] Has anyone been able to enable WiFi channels 12-14?

Hi,

I've tried the following:

/system/build.prop:
ro.product.locale.region=JP
ro.wifi.channels=14

/data/data/com.android.providers.settings/databases/settings.db (global table):
wifi_country_code='jp'

None of this worked.
I'm on stock rooted KK ROM (ANK4).