--- a/usr/src/uts/common/io/urtw/urtw.c	Mon Sep 21 21:41:02 2009 -0600
+++ b/usr/src/uts/common/io/urtw/urtw.c	Tue Sep 22 12:05:08 2009 +0800
@@ -3539,7 +3539,7 @@
 	if ((type & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_DATA) {
 		buf[3] = urtw_rate2rtl(MAX(2, urtw_get_rate(ic)));
 	} else
-		buf[3] = sc->sc_currate;
+		buf[3] = 0;
 
 	if (sc->sc_hwrev & URTW_HWREV_8187) {
 		buf[8] = 3;		/* CW minimum  */