diff --git a/os/kernel/include/chvt.h b/os/kernel/include/chvt.h
index 63ff3c4b3..97a04d81e 100644
--- a/os/kernel/include/chvt.h
+++ b/os/kernel/include/chvt.h
@@ -43,7 +43,8 @@
  *
  * @api
  */
-#define S2ST(sec)   ((systime_t)((sec) * CH_FREQUENCY))
+#define S2ST(sec)                                                           \
+  ((systime_t)((sec) * CH_FREQUENCY))
 
 /**
  * @brief   Milliseconds to system ticks.
@@ -55,8 +56,8 @@
  *
  * @api
  */
-#define MS2ST(msec) ((systime_t)(((((msec) - 1L) * CH_FREQUENCY) /          \
-                                   1000L) + 1L))
+#define MS2ST(msec)                                                         \
+  ((systime_t)((((msec) * CH_FREQUENCY - 1L) / 1000L) + 1L))
 
 /**
  * @brief   Microseconds to system ticks.
@@ -68,8 +69,8 @@
  *
  * @api
  */
-#define US2ST(usec) ((systime_t)(((((usec) - 1L) * CH_FREQUENCY) /          \
-                                  1000000L) + 1L))
+#define US2ST(usec)                                                         \
+  ((systime_t)((((usec) * CH_FREQUENCY - 1L) / 1000000L) + 1L))
 /** @} */
 
 /**
diff --git a/readme.txt b/readme.txt
index 953b51cec..adf5773f2 100644
--- a/readme.txt
+++ b/readme.txt
@@ -89,6 +89,8 @@
 *****************************************************************************
 
 *** 2.5.2 ***
+- FIX: Fixed  MS2ST() and US2ST() macros error (bug #415)(backported to 2.4.4,
+  2.2.10, NilRTOS).
 - FIX: Fixed lwipthread.h should explicitly include lwip/opts.h (bug #414).
 - FIX: Fixed STM32_PLLI2SCLKOUT miscalculated (bug #413)(backported to 2.4.4).
 - FIX: Fixed wrong RTC vector name in STM32F1/F4/L1 EXT drivers (bug #412).
diff --git a/testhal/SPC563Mxx/SPI/main.c b/testhal/SPC563Mxx/SPI/main.c
index 25b67546b..46378a5f8 100644
--- a/testhal/SPC563Mxx/SPI/main.c
+++ b/testhal/SPC563Mxx/SPI/main.c
@@ -152,6 +152,7 @@ int main(void) {
    */
   while (TRUE) {
     chThdSleepMilliseconds(500);
+    palTogglePad(PORT11, P11_LED2);
   }
   return 0;
 }