--- a/sys/dev/netif/iwm/if_iwm.c	2026-09-15 10:51:39.216775004 +0000
+++ b/sys/dev/netif/iwm/if_iwm.c	2026-09-15 10:51:59.600513253 +0000
@@ -5707,7 +5707,7 @@
 		wreg = IWM_FH_RSCSR_CHNL0_WPTR;
 	}
 
-	hw = le16toh(sc->rxq.stat->closed_rb_num) & 0xfff;
+	hw = le16toh(sc->rxq.stat->closed_rb_num) & (count - 1);
 
 	/*
 	 * Process responses