diff --git a/tools/sdk/lwip2/builder b/tools/sdk/lwip2/builder
index 6f4189880..11d2224d2 160000
--- a/tools/sdk/lwip2/builder
+++ b/tools/sdk/lwip2/builder
@@ -1 +1 @@
-Subproject commit 6f418988085a7d30eee5ddfcad961de461e4aa60
+Subproject commit 11d2224d2072192a668ea6f9f99f43fdf78b3c90
diff --git a/tools/sdk/lwip2/include/gluedebug.h b/tools/sdk/lwip2/include/gluedebug.h
index 8750d6132..71bc30efc 100644
--- a/tools/sdk/lwip2/include/gluedebug.h
+++ b/tools/sdk/lwip2/include/gluedebug.h
@@ -43,7 +43,7 @@ extern int doprint_allow;
 #define USE_OPTIMIZE_PRINTF	// at least used in arduino/esp8266
 #endif
 // os_printf_plus() missing in osapi.h (fixed in arduino's sdk-2.1):
-extern int os_printf_plus (const char * format, ...) __attribute__ ((format (printf, 1, 2)));
+//extern int os_printf_plus (const char * format, ...) __attribute__ ((format (printf, 1, 2)));
 
 #include <osapi.h> // os_printf* definitions + ICACHE_RODATA_ATTR