diff --git a/src/core/ipv4/ip4_frag.c b/src/core/ipv4/ip4_frag.c
index 50edd121..8f65b736 100644
--- a/src/core/ipv4/ip4_frag.c
+++ b/src/core/ipv4/ip4_frag.c
@@ -160,7 +160,7 @@ static int
 ip_reass_free_complete_datagram(struct ip_reassdata *ipr, struct ip_reassdata *prev)
 {
   u16_t pbufs_freed = 0;
-  u8_t clen;
+  u16_t clen;
   struct pbuf *p;
   struct ip_reass_helper *iprh;
 
@@ -487,8 +487,7 @@ ip4_reass(struct pbuf *p)
   struct ip_hdr *fraghdr;
   struct ip_reassdata *ipr;
   struct ip_reass_helper *iprh;
-  u16_t offset, len;
-  u8_t clen;
+  u16_t offset, len, clen;
 
   IPFRAG_STATS_INC(ip_frag.recv);
   MIB2_STATS_INC(mib2.ipreasmreqds);
diff --git a/src/core/ipv6/ip6_frag.c b/src/core/ipv6/ip6_frag.c
index f41d167f..a7e88e4f 100644
--- a/src/core/ipv6/ip6_frag.c
+++ b/src/core/ipv6/ip6_frag.c
@@ -147,7 +147,7 @@ ip6_reass_free_complete_datagram(struct ip6_reassdata *ipr)
 {
   struct ip6_reassdata *prev;
   u16_t pbufs_freed = 0;
-  u8_t clen;
+  u16_t clen;
   struct pbuf *p;
   struct ip6_reass_helper *iprh;
 
@@ -262,7 +262,8 @@ ip6_reass(struct pbuf *p)
   struct ip6_reass_helper *iprh, *iprh_tmp, *iprh_prev=NULL;
   struct ip6_frag_hdr *frag_hdr;
   u16_t offset, len;
-  u8_t clen, valid = 1;
+  u16_t clen;
+  u8_t valid = 1;
   struct pbuf *q;
 
   IP6_FRAG_STATS_INC(ip6_frag.recv);
diff --git a/src/core/netif.c b/src/core/netif.c
index 3f074813..9bbd8246 100644
--- a/src/core/netif.c
+++ b/src/core/netif.c
@@ -791,7 +791,7 @@ netif_loop_output(struct netif *netif, struct pbuf *p)
   err_t err;
   struct pbuf *last;
 #if LWIP_LOOPBACK_MAX_PBUFS
-  u8_t clen = 0;
+  u16_t clen = 0;
 #endif /* LWIP_LOOPBACK_MAX_PBUFS */
   /* If we have a loopif, SNMP counters are adjusted for it,
    * if not they are adjusted for 'netif'. */
diff --git a/src/core/pbuf.c b/src/core/pbuf.c
index a145dffc..b45ea8c9 100644
--- a/src/core/pbuf.c
+++ b/src/core/pbuf.c
@@ -779,10 +779,10 @@ pbuf_free(struct pbuf *p)
  * @param p first pbuf of chain
  * @return the number of pbufs in a chain
  */
-u8_t
+u16_t
 pbuf_clen(struct pbuf *p)
 {
-  u8_t len;
+  u16_t len;
 
   len = 0;
   while (p != NULL) {
diff --git a/src/include/lwip/pbuf.h b/src/include/lwip/pbuf.h
index bc7296e0..d79d1717 100644
--- a/src/include/lwip/pbuf.h
+++ b/src/include/lwip/pbuf.h
@@ -231,7 +231,7 @@ u8_t pbuf_header(struct pbuf *p, s16_t header_size);
 u8_t pbuf_header_force(struct pbuf *p, s16_t header_size);
 void pbuf_ref(struct pbuf *p);
 u8_t pbuf_free(struct pbuf *p);
-u8_t pbuf_clen(struct pbuf *p);
+u16_t pbuf_clen(struct pbuf *p);
 void pbuf_cat(struct pbuf *head, struct pbuf *tail);
 void pbuf_chain(struct pbuf *head, struct pbuf *tail);
 struct pbuf *pbuf_dechain(struct pbuf *p);