diff --git a/src/core/init.c b/src/core/init.c
index bf5c79da..513434ee 100644
--- a/src/core/init.c
+++ b/src/core/init.c
@@ -56,6 +56,7 @@
 #include "lwip/dns.h"
 #include "lwip/timers.h"
 #include "netif/etharp.h"
+#include "lwip/api.h"
 
 /* Compile-time sanity checks for configuration errors.
  * These can be done independently of LWIP_DEBUG, without penalty.
@@ -187,6 +188,32 @@
 #if IP_FRAG && IP_FRAG_USES_STATIC_BUF && LWIP_NETIF_TX_SINGLE_PBUF
   #error "LWIP_NETIF_TX_SINGLE_PBUF does not work with IP_FRAG_USES_STATIC_BUF==1 as that creates pbuf queues"
 #endif
+#if LWIP_NETCONN && LWIP_TCP
+#if NETCONN_COPY != TCP_WRITE_FLAG_COPY
+  #error "NETCONN_COPY != TCP_WRITE_FLAG_COPY"
+#endif
+#if NETCONN_MORE != TCP_WRITE_FLAG_MORE
+  #error "NETCONN_MORE != TCP_WRITE_FLAG_MORE"
+#endif
+#endif /* LWIP_NETCONN && LWIP_TCP */ 
+#if LWIP_SOCKET
+/* Check that the SO_* socket options and SOF_* lwIP-internal flags match */
+#if SO_ACCEPTCONN != SOF_ACCEPTCONN
+  #error "SO_ACCEPTCONN != SOF_ACCEPTCONN"
+#endif
+#if SO_REUSEADDR != SOF_REUSEADDR
+  #error "WARNING: SO_REUSEADDR != SOF_REUSEADDR"
+#endif
+#if SO_KEEPALIVE != SOF_KEEPALIVE
+  #error "WARNING: SO_KEEPALIVE != SOF_KEEPALIVE"
+#endif
+#if SO_BROADCAST != SOF_BROADCAST
+  #error "WARNING: SO_BROADCAST != SOF_BROADCAST"
+#endif
+#if SO_LINGER != SOF_LINGER
+  #error "WARNING: SO_LINGER != SOF_LINGER"
+#endif
+#endif /* LWIP_SOCKET */
 
 
 /* Compile-time checks for deprecated options.
@@ -235,19 +262,6 @@ lwip_sanity_check(void)
   if (TCP_WND < TCP_MSS)
     LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: TCP_WND is smaller than MSS\n"));
 #endif /* LWIP_TCP */
-#if LWIP_SOCKET
-  /* Check that the SO_* socket options and SOF_* lwIP-internal flags match */
-  if (SO_ACCEPTCONN != SOF_ACCEPTCONN)
-    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_ACCEPTCONN != SOF_ACCEPTCONN\n"));
-  if (SO_REUSEADDR != SOF_REUSEADDR)
-    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_REUSEADDR != SOF_REUSEADDR\n"));
-  if (SO_KEEPALIVE != SOF_KEEPALIVE)
-    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_KEEPALIVE != SOF_KEEPALIVE\n"));
-  if (SO_BROADCAST != SOF_BROADCAST)
-    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_BROADCAST != SOF_BROADCAST\n"));
-  if (SO_LINGER != SOF_LINGER)
-    LWIP_PLATFORM_DIAG(("lwip_sanity_check: WARNING: SO_LINGER != SOF_LINGER\n"));
-#endif /* LWIP_SOCKET */
 }
 #else  /* LWIP_DEBUG */
 #define lwip_sanity_check()
diff --git a/src/include/ipv4/lwip/ip.h b/src/include/ipv4/lwip/ip.h
index 74f501d1..2c000e4b 100644
--- a/src/include/ipv4/lwip/ip.h
+++ b/src/include/ipv4/lwip/ip.h
@@ -94,16 +94,16 @@ struct ip_pcb {
 /*
  * Option flags per-socket. These are the same like SO_XXX.
  */
-/*#define SOF_DEBUG       (u8_t)0x01U     Unimplemented: turn on debugging info recording */
-#define SOF_ACCEPTCONN    (u8_t)0x02U  /* socket has had listen() */
-#define SOF_REUSEADDR     (u8_t)0x04U  /* allow local address reuse */
-#define SOF_KEEPALIVE     (u8_t)0x08U  /* keep connections alive */
-/*#define SOF_DONTROUTE   (u8_t)0x10U     Unimplemented: just use interface addresses */
-#define SOF_BROADCAST     (u8_t)0x20U  /* permit to send and to receive broadcast messages (see IP_SOF_BROADCAST option) */
-/*#define SOF_USELOOPBACK (u8_t)0x40U     Unimplemented: bypass hardware when possible */
-#define SOF_LINGER        (u8_t)0x80U  /* linger on close if data present */
-/*#define SOF_OOBINLINE   (u16_t)0x0100U     Unimplemented: leave received OOB data in line */
-/*#define SOF_REUSEPORT   (u16_t)0x0200U     Unimplemented: allow local address & port reuse */
+/*#define SOF_DEBUG       0x01U     Unimplemented: turn on debugging info recording */
+#define SOF_ACCEPTCONN    0x02U  /* socket has had listen() */
+#define SOF_REUSEADDR     0x04U  /* allow local address reuse */
+#define SOF_KEEPALIVE     0x08U  /* keep connections alive */
+/*#define SOF_DONTROUTE   0x10U     Unimplemented: just use interface addresses */
+#define SOF_BROADCAST     0x20U  /* permit to send and to receive broadcast messages (see IP_SOF_BROADCAST option) */
+/*#define SOF_USELOOPBACK 0x40U     Unimplemented: bypass hardware when possible */
+#define SOF_LINGER        0x80U  /* linger on close if data present */
+/*#define SOF_OOBINLINE   0x0100U   Unimplemented: leave received OOB data in line */
+/*#define SOF_REUSEPORT   0x0200U   Unimplemented: allow local address & port reuse */
 
 /* These flags are inherited (e.g. from a listen-pcb to a connection-pcb): */
 #define SOF_INHERITED   (SOF_REUSEADDR|SOF_KEEPALIVE|SOF_LINGER/*|SOF_DEBUG|SOF_DONTROUTE|SOF_OOBINLINE*/)