diff --git a/net/caif/cfrfml.c b/net/caif/cfrfml.c
index 4b04d25b6a3f..eb1602022ac0 100644
--- a/net/caif/cfrfml.c
+++ b/net/caif/cfrfml.c
@@ -193,7 +193,7 @@ static int cfrfml_receive(struct cflayer *layr, struct cfpkt *pkt)
 
 static int cfrfml_transmit_segment(struct cfrfml *rfml, struct cfpkt *pkt)
 {
-	caif_assert(!cfpkt_getlen(pkt) < rfml->fragment_size);
+	caif_assert(cfpkt_getlen(pkt) >= rfml->fragment_size);
 
 	/* Add info for MUX-layer to route the packet out. */
 	cfpkt_info(pkt)->channel_id = rfml->serv.layer.id;