diff --git a/include/linux/ieee802154.h b/include/linux/ieee802154.h
index 40b0ab9..8872ca1 100644
--- a/include/linux/ieee802154.h
+++ b/include/linux/ieee802154.h
@@ -30,6 +30,7 @@
 #define IEEE802154_MTU			127
 #define IEEE802154_ACK_PSDU_LEN		5
 #define IEEE802154_MIN_PSDU_LEN		9
+#define IEEE802154_FCS_LEN		2
 
 #define IEEE802154_PAN_ID_BROADCAST	0xffff
 #define IEEE802154_ADDR_SHORT_BROADCAST	0xffff
@@ -39,6 +40,7 @@
 
 #define IEEE802154_LIFS_PERIOD		40
 #define IEEE802154_SIFS_PERIOD		12
+#define IEEE802154_MAX_SIFS_FRAME_SIZE	18
 
 #define IEEE802154_MAX_CHANNEL		26
 #define IEEE802154_MAX_PAGE		31
diff --git a/net/mac802154/util.c b/net/mac802154/util.c
index 5fc9790..150bf80 100644
--- a/net/mac802154/util.c
+++ b/net/mac802154/util.c
@@ -65,8 +65,19 @@
 {
 	if (ifs_handling) {
 		struct ieee802154_local *local = hw_to_local(hw);
+		u8 max_sifs_size;
 
-		if (skb->len > 18)
+		/* If transceiver sets CRC on his own we need to use lifs
+		 * threshold len above 16 otherwise 18, because it's not
+		 * part of skb->len.
+		 */
+		if (hw->flags & IEEE802154_HW_TX_OMIT_CKSUM)
+			max_sifs_size = IEEE802154_MAX_SIFS_FRAME_SIZE -
+					IEEE802154_FCS_LEN;
+		else
+			max_sifs_size = IEEE802154_MAX_SIFS_FRAME_SIZE;
+
+		if (skb->len > max_sifs_size)
 			hrtimer_start(&local->ifs_timer,
 				      ktime_set(0, hw->phy->lifs_period * NSEC_PER_USEC),
 				      HRTIMER_MODE_REL);