diff --git a/features/lwipstack/lwip-sys/arch/cc.h b/features/lwipstack/lwip-sys/arch/cc.h
index 2510a11cfc..5d68b8e780 100644
--- a/features/lwipstack/lwip-sys/arch/cc.h
+++ b/features/lwipstack/lwip-sys/arch/cc.h
@@ -110,7 +110,7 @@ MBED_NORETURN void lwip_mbed_assert_fail(const char *msg, const char *func, cons
 #else // MBED_CONF_LWIP_USE_MBED_TRACE
 #include <stdio.h>
 
-MBED_NORETURN void assert_printf(char *msg, int line, char *file);
+MBED_NORETURN void assert_printf(const char *msg, int line, const char *file);
 
 /* Plaform specific diagnostic output */
 #define LWIP_PLATFORM_DIAG(vars) printf vars
diff --git a/features/lwipstack/lwip-sys/arch/lwip_sys_arch.c b/features/lwipstack/lwip-sys/arch/lwip_sys_arch.c
index 93e7128af5..552f622a68 100644
--- a/features/lwipstack/lwip-sys/arch/lwip_sys_arch.c
+++ b/features/lwipstack/lwip-sys/arch/lwip_sys_arch.c
@@ -611,7 +611,7 @@ MBED_NORETURN void lwip_mbed_assert_fail(const char *msg, const char *func, cons
     \param[in]    line  Line number in file with error
     \param[in]    file  Filename with error
  */
-MBED_NORETURN void assert_printf(char *msg, int line, char *file) {
+MBED_NORETURN void assert_printf(const char *msg, int line, const char *file) {
     if (msg)
         error("%s:%d in file %s\n", msg, line, file);
     else