diff --git a/os/hal/include/serial.h b/os/hal/include/serial.h
index e321d5585..de2572f39 100644
--- a/os/hal/include/serial.h
+++ b/os/hal/include/serial.h
@@ -60,7 +60,7 @@
  * @details Configuration parameter, this is the baud rate selected for the
  *          default configuration.
  */
-#if !defined(DEFAULT_USART_BITRATE) || defined(__DOXYGEN__)
+#if !defined(SERIAL_DEFAULT_BITRATE) || defined(__DOXYGEN__)
 #define SERIAL_DEFAULT_BITRATE      38400
 #endif
 
diff --git a/readme.txt b/readme.txt
index 564898d1a..74624039d 100644
--- a/readme.txt
+++ b/readme.txt
@@ -57,6 +57,7 @@
 *****************************************************************************
 
 *** 1.5.6 ***
+- FIX: Fixed wrong macro check in serial.h (bug 2989459)(backported in 1.4.3).
 - Various documentation fixes.
 
 *** 1.5.5 ***