openwrt/package/hostapd/patches/450-reload_freq_change.patch

--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -137,6 +137,10 @@ int hostapd_reload_config(struct hostapd
 	oldconf = hapd->iconf;
 	iface->conf = newconf;
 
+	iface->freq = hostapd_hw_get_freq(hapd, hapd->iconf->channel);
+	if (iface->current_mode)
+		hostapd_prepare_rates(iface, iface->current_mode);
+
 	for (j = 0; j < iface->num_bss; j++) {
 		hapd = iface->bss[j];
 		hapd->iconf = newconf;