diff --git a/sys/dev/bwi/if_bwivar.h b/sys/dev/bwi/if_bwivar.h
--- a/sys/dev/bwi/if_bwivar.h
+++ b/sys/dev/bwi/if_bwivar.h
@@ -305,7 +305,7 @@
 	union {
 		uint32_t	val32;
 		uint16_t	val16;
-	} 			iv_val;
+	} __packed		iv_val;
 } __packed;
 
 #define BWI_FW_IV_OFS_MASK	__BITS(14, 0)