diff --git a/components/newlib/time.c b/components/newlib/time.c
index a021d15eee..4a0bfb01da 100644
--- a/components/newlib/time.c
+++ b/components/newlib/time.c
@@ -137,6 +137,7 @@ int adjtime(const struct timeval *delta, struct timeval *outdelta)
         int64_t sec  = delta->tv_sec;
         int64_t usec = delta->tv_usec;
         if(llabs(sec) > ((INT_MAX / 1000000L) - 1L)) {
+            errno = EINVAL;
             return -1;
         }
         /*
@@ -153,6 +154,7 @@ int adjtime(const struct timeval *delta, struct timeval *outdelta)
     }
     return 0;
 #else
+    errno = ENOSYS;
     return -1;
 #endif
 }