diff --git a/cores/esp8266/Stream.cpp b/cores/esp8266/Stream.cpp
index a29388b2bf..3d7f5bc23f 100644
--- a/cores/esp8266/Stream.cpp
+++ b/cores/esp8266/Stream.cpp
@@ -33,6 +33,8 @@ int Stream::timedRead() {
         c = read();
         if(c >= 0)
             return c;
+        if(_timeout == 0)
+            return -1;
         yield();
     } while(millis() - _startMillis < _timeout);
     return -1;     // -1 indicates timeout
@@ -46,6 +48,8 @@ int Stream::timedPeek() {
         c = peek();
         if(c >= 0)
             return c;
+        if(_timeout == 0)
+            return -1;
         yield();
     } while(millis() - _startMillis < _timeout);
     return -1;     // -1 indicates timeout
@@ -254,4 +258,3 @@ String Stream::readStringUntil(char terminator) {
     }
     return ret;
 }
-