Download and install the FF6_6.6.6.9.201_FCC.apk (thanks for ds2atc) Before that, delete the factory (original) app along with the directories. This app automatically sets a country where FCC power is enabled, so you don't have to do anything.
after connecting you should see channels on the wifi chart that 36,40,44,48 are then probably in FCC.
Look before and after and you can see the change.
