diff --git a/library.json b/library.json
index ef4b0b2..c50131f 100644
--- a/library.json
+++ b/library.json
@@ -1,6 +1,6 @@
 {
     "name": "EspSoftwareSerial",
-    "version": "5.3.3",
+    "version": "5.3.4",
     "keywords": [
       "serial", "io", "softwareserial"
     ],
diff --git a/library.properties b/library.properties
index b04b486..b0ad23d 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=EspSoftwareSerial
-version=5.3.3
+version=5.3.4
 author=Peter Lerup, Dirk Kaar
 maintainer=Peter Lerup <peter@lerup.com>
 sentence=Implementation of the Arduino software serial for ESP8266/ESP32.
diff --git a/src/SoftwareSerial.cpp b/src/SoftwareSerial.cpp
index 34474bd..eb09944 100644
--- a/src/SoftwareSerial.cpp
+++ b/src/SoftwareSerial.cpp
@@ -274,6 +274,7 @@ size_t ICACHE_RAM_ATTR SoftwareSerial::write(const uint8_t * buffer, size_t size
 }
 
 void SoftwareSerial::flush() {
+    if (!m_rxValid) { return; }
     m_buffer->flush();
 }