diff --git a/os/hal/include/serial.h b/os/hal/include/serial.h
index 535dffc1f..25e046d6e 100644
--- a/os/hal/include/serial.h
+++ b/os/hal/include/serial.h
@@ -137,7 +137,7 @@ struct SerialDriver {
  *
  * @api
  */
-#define sdPutWouldBlock(sdp) chOQIsFull(&(sdp)->oqueue)
+#define sdPutWouldBlock(sdp) chOQIsFullI(&(sdp)->oqueue)
 
 /**
  * @brief   Direct input check on a @p SerialDriver.
@@ -149,7 +149,7 @@ struct SerialDriver {
  *
  * @api
  */
-#define sdGetWouldBlock(sdp) chIQIsEmpty(&(sdp)->iqueue)
+#define sdGetWouldBlock(sdp) chIQIsEmptyI(&(sdp)->iqueue)
 
 /**
  * @brief   Direct write to a @p SerialDriver.
diff --git a/readme.txt b/readme.txt
index ee93ad91d..5ce5777ad 100644
--- a/readme.txt
+++ b/readme.txt
@@ -69,6 +69,7 @@
 *****************************************************************************
 
 *** 2.3.0 ***
+- FIX: Fixed wrong serial driver macros (bug 3173336)(backported to 2.2.1).
 - NEW: Added experimental generic USB driver, it will certainly change in next
   releases.
 - NEW: Added an experimental USB driver implementation for STM32.