Index: head/sys/dev/bwn/if_bwn.c
===================================================================
--- head/sys/dev/bwn/if_bwn.c
+++ head/sys/dev/bwn/if_bwn.c
@@ -9467,7 +9467,7 @@
 	struct mbuf *mprot;
 	unsigned int len;
 	uint32_t macctl = 0;
-	int protdur, rts_rate, rts_rate_fb, ismcast, isshort, rix, type;
+	int protdur, rts_rate, rts_rate_fb, ismcast, isshort, nrates, type;
 	uint16_t phyctl = 0;
 	uint8_t rate, rate_fb;
 
@@ -9489,11 +9489,12 @@
 	else if (tp->ucastrate != IEEE80211_FIXED_RATE_NONE)
 		rate = rate_fb = tp->ucastrate;
 	else {
-		rix = ieee80211_ratectl_rate(ni, NULL, 0);
+		ieee80211_ratectl_rate(ni, NULL, 0);
+		nrates = ni->ni_rates.rs_nrates;
 		rate = ni->ni_txrate;
 
-		if (rix > 0)
-			rate_fb = ni->ni_rates.rs_rates[rix - 1] &
+		if (nrates > 0)
+			rate_fb = ni->ni_rates.rs_rates[nrates - 1] &
 			    IEEE80211_RATE_VAL;
 		else
 			rate_fb = rate;