diff --git a/tools/sdk/lib/liblwip2.a b/tools/sdk/lib/liblwip2.a
index 223ee7cb7..abdcd7d43 100644
Binary files a/tools/sdk/lib/liblwip2.a and b/tools/sdk/lib/liblwip2.a differ
diff --git a/tools/sdk/lib/liblwip2_1460.a b/tools/sdk/lib/liblwip2_1460.a
index f0307b182..a2d8d0cf3 100644
Binary files a/tools/sdk/lib/liblwip2_1460.a and b/tools/sdk/lib/liblwip2_1460.a differ
diff --git a/tools/sdk/lwip2/builder b/tools/sdk/lwip2/builder
index bdd68addc..4c1f9e77c 160000
--- a/tools/sdk/lwip2/builder
+++ b/tools/sdk/lwip2/builder
@@ -1 +1 @@
-Subproject commit bdd68addcfed8f2e3b484b465369dac0407d3f5e
+Subproject commit 4c1f9e77c59a5ab97fb650fe0f2a9c46fcc7483c
diff --git a/tools/sdk/lwip2/include/gluedebug.h b/tools/sdk/lwip2/include/gluedebug.h
index 03c9a1781..55d0e8d74 100644
--- a/tools/sdk/lwip2/include/gluedebug.h
+++ b/tools/sdk/lwip2/include/gluedebug.h
@@ -17,7 +17,7 @@
 #define ULWIPDEBUG	0	// 0 or 1 (trigger lwip debug)
 #define ULWIPASSERT	0	// 0 or 1 (trigger lwip self-check, 0 saves flash)
 
-#define STRING_IN_FLASH 0	// *print("fmt is stored in flash")
+#define STRING_IN_FLASH 1	// *print("fmt is stored in flash")
 
 #define ROTBUFLEN_BIT	11	// (UDEBUGSTORE=1) doprint()'s buffer: 11=2048B
 
@@ -82,10 +82,7 @@ int doprint_minus (const char* format, ...) __attribute__ ((format (printf, 1, 2
 #define uprint(x...)		do { (void)0; } while (0)
 #endif
 
-#if UNDEBUG
-#define uassert(assertion...)   do { (void)0; } while (0)
-#else // !defined(UNDEBUG)
-#define uassert(assertion...)	\
+#define udoassert(assertion...)	\
 do { if ((assertion) == 0) { \
 		static const char assrt[] ICACHE_RODATA_ATTR STORE_ATTR = #assertion " wrong@"; \
 		os_printf_plus(assrt); \
@@ -95,8 +92,15 @@ do { if ((assertion) == 0) { \
 		os_printf_plus(assrt_line, __LINE__); \
 		uhalt(); \
 } } while (0)
+
+#if UNDEBUG
+#define uassert(assertion...)	do { (void)0; } while (0)
+#else // !defined(UNDEBUG)
+#define uassert(assertion...)	udoassert(assertion)
 #endif // !defined(UNDEBUG)
 
+#define ualwaysassert(assertion...)	udoassert(assertion)
+
 #define uerror(x...)		do { doprint(x); } while (0)
 #define uhalt() 		do { *((int*)0) = 0; /* this triggers gdb */ } while (0)
 #define nl()			do { uprint("\n"); } while (0)
diff --git a/tools/sdk/lwip2/include/lwip-git-hash.h b/tools/sdk/lwip2/include/lwip-git-hash.h
index 587ff5854..c4b8143ef 100644
--- a/tools/sdk/lwip2/include/lwip-git-hash.h
+++ b/tools/sdk/lwip2/include/lwip-git-hash.h
@@ -1,6 +1,5 @@
 // generated by makefiles/make-lwip2-hash
 #ifndef LWIP_HASH_H
 #define LWIP_HASH_H
-#define LWIP_HASH 0x92f23d6
-#define LWIP_HASH_STR "92f23d6(tag:STABLE-2_0_3_RELEASE)"
+#define LWIP_HASH_STR "STABLE-2_0_3_RELEASE/glue:arduino-2.4.0-7-g7c20da9"
 #endif // LWIP_HASH_H