Miracle wrote

I am from Vietnam, I reflash EU firmware but can not use channel 12, 13 on EAP 225.

A Federal Communications Commission (FCC) document clarifies that only channel 14 is forbidden and that low-power transmitters with low-gain antennas may operate legally in channels 12 and 13. Channels 12 and 13, however, are not normally used in order to avoid any potential interference in the adjacent restricted frequency band, 2,483.5–2,500 MHz, which is subject to strict emission limits set out in 47 CFR § 15.205.