diff --git a/wled00/src/dependencies/dmx/SparkFunDMX.cpp b/wled00/src/dependencies/dmx/SparkFunDMX.cpp
index d862f2b8..1241dba6 100644
--- a/wled00/src/dependencies/dmx/SparkFunDMX.cpp
+++ b/wled00/src/dependencies/dmx/SparkFunDMX.cpp
@@ -153,7 +153,7 @@ void SparkFunDMX::update() {
     
     //Send DMX data
     DMXSerial.begin(DMXSPEED, DMXFORMAT, rxPin, txPin);//Begin the Serial port
-    DMXSerial.write(dmxData, min(dmxMaxChannel, chanSize));
+    DMXSerial.write(dmxData, min(dmxMaxChannel+1, chanSize)); // send max 513 bytes = start byte + 512 channels
     DMXSerial.flush();
     DMXSerial.end();//clear our DMX array, end the Hardware Serial port
   }