diff --git a/os/hal/platforms/STM32/serial_lld.h b/os/hal/platforms/STM32/serial_lld.h
index 011dd865a..128920860 100644
--- a/os/hal/platforms/STM32/serial_lld.h
+++ b/os/hal/platforms/STM32/serial_lld.h
@@ -79,7 +79,7 @@
  * @details If set to @p TRUE the support for UART5 is included.
  * @note    The default is @p FALSE.
  */
-#if !defined(STM32_SERIAL_USE_USART3) || defined(__DOXYGEN__)
+#if !defined(STM32_SERIAL_USE_UART5) || defined(__DOXYGEN__)
 #define STM32_SERIAL_USE_UART5              TRUE
 #endif
 
diff --git a/readme.txt b/readme.txt
index bb0e4e41c..e9d42154e 100644
--- a/readme.txt
+++ b/readme.txt
@@ -62,6 +62,8 @@
 *****************************************************************************
 
 *** 2.1.2 ***
+- FIX: Fixed wrong macro check in STM32 serial support (but 3078891)(backported
+  to 2.0.6).
 - FIX: Fixed non functioning option CH_USE_NESTED_LOCKS (bug 3075544)
   (backported to 2.0.6).
 - FIX: Incorrect AT91SAM7X initialization, thanks Leszek (bug 3075354)