diff --git a/cpu/sam3x8e/syscalls.c b/cpu/sam3x8e/syscalls.c
index f060896592..3daae2d462 100644
--- a/cpu/sam3x8e/syscalls.c
+++ b/cpu/sam3x8e/syscalls.c
@@ -156,7 +156,8 @@ pid_t _getpid(void)
  *
  * @return      TODO
  */
-int _kill_r(struct _reent *r, pid_t pid, int sig)
+__attribute__ ((weak))
+int _kill_r(struct _reent *r, int pid, int sig)
 {
     r->_errno = ESRCH;                      /* not implemented yet */
     return -1;
@@ -323,3 +324,18 @@ int _unlink_r(struct _reent *r, char* path)
     r->_errno = ENODEV;                     /* not implemented yet */
     return -1;
 }
+
+/**
+ * @brief Send a signal to a thread
+ *
+ * @param[in] pid the pid to send to
+ * @param[in] sig the signal to send
+ *
+ * @return TODO
+ */
+__attribute__ ((weak))
+int _kill(int pid, int sig)
+{
+    errno = ESRCH;                         /* not implemented yet */
+    return -1;
+}