diff --git a/os/various/syscalls.c b/os/various/syscalls.c
index 7467b63ce..e52931845 100644
--- a/os/various/syscalls.c
+++ b/os/various/syscalls.c
@@ -140,6 +140,7 @@ int _close_r(struct _reent *r, int file)
 
 caddr_t _sbrk_r(struct _reent *r, int incr)
 {
+#if CH_USE_MEMCORE
   void *p;
 
   chDbgCheck(incr > 0, "_sbrk_r");
@@ -151,6 +152,10 @@ caddr_t _sbrk_r(struct _reent *r, int incr)
     return (caddr_t)-1;
   }
   return (caddr_t)p;
+#else
+  __errno_r(r) = ENOMEM;
+  return (caddr_t)-1;
+#endif
 }
 
 /***************************************************************************/
diff --git a/readme.txt b/readme.txt
index 0a143552b..17527f211 100644
--- a/readme.txt
+++ b/readme.txt
@@ -79,6 +79,7 @@
 *****************************************************************************
 
 *** 2.4.3 ***
+- FIX: Fixed compilation issue in syscalls.c (bug 3575657).
 - FIX: Fixed superfluous pack #defines cause nasty warning (bug 3575662).
 - FIX: Fixed mac.c won't compile due to misplaced declarations (bug 3575657).
 - FIX: Fixed STM32F4 ADC prescaler incorrectly initialized (bug 3575297).