diff --git a/os/hal/platforms/STM32F2xx/hal_lld.h b/os/hal/platforms/STM32F2xx/hal_lld.h
index 4d63324ce..736853605 100644
--- a/os/hal/platforms/STM32F2xx/hal_lld.h
+++ b/os/hal/platforms/STM32F2xx/hal_lld.h
@@ -341,7 +341,7 @@
 
 /* RTC attributes.*/
 #define STM32_HAS_RTC           TRUE
-#define STM32_RTC_HAS_SUBSECONDS TRUE
+#define STM32_RTC_HAS_SUBSECONDS FALSE
 #define STM32_RTC_IS_CALENDAR   TRUE
 
 /* SDIO attributes.*/
diff --git a/readme.txt b/readme.txt
index 9207188e7..5fdacd8af 100644
--- a/readme.txt
+++ b/readme.txt
@@ -81,6 +81,7 @@
 *****************************************************************************
 
 *** 2.5.0 ***
+- FIX: Fixed STM32F2 RTC subseconds (bug 3533414)(backported to 2.4.2).
 - FIX: Fixed problem with arm-v6m and state checker (bug 3532591)(backported
   to 2.4.2).
 - FIX: Fixed wrong MAC divider setting in STM32 MAC driver (bug 3531290)