diff --git a/SerialPort.h b/SerialPort.h
index ebe3dff..7c08b8d 100644
--- a/SerialPort.h
+++ b/SerialPort.h
@@ -285,7 +285,7 @@ public:
     void writeDump(const uint8_t* data, uint16_t length);
 
 private:
-    uint8_t m_buffer[256U];
+    uint8_t m_buffer[518U];
     uint8_t m_ptr;
     uint16_t m_len;
     bool m_dblFrame;