diff --git a/os/common/ports/ARMCMx/devices/STM32F4xx/cmparams.h b/os/common/ports/ARMCMx/devices/STM32F4xx/cmparams.h
index 43277ee96..e742a7e66 100644
--- a/os/common/ports/ARMCMx/devices/STM32F4xx/cmparams.h
+++ b/os/common/ports/ARMCMx/devices/STM32F4xx/cmparams.h
@@ -57,7 +57,7 @@
  * @note    This number does not include the 16 system vectors and must be
  *          rounded to a multiple of 8.
  */
-#define CORTEX_NUM_VECTORS      88
+#define CORTEX_NUM_VECTORS      96
 
 /* The following code is not processed when the file is included from an
    asm module.*/
@@ -66,7 +66,8 @@
 /* If the device type is not externally defined, for example from the Makefile,
    then a file named board.h is included. This file must contain a device
    definition compatible with the vendor include file.*/
-#if !defined(STM32F40XX) && !defined(STM32F427X)
+#if !defined(STM32F40_41xxx) && !defined(STM32F427_437xx) &&                \
+    !defined(STM32F429_439xx) && !defined(STM32F401xx)
 #include "board.h"
 #endif
 
diff --git a/os/rt/include/chsys.h b/os/rt/include/chsys.h
index 9a74788ae..1b80bba65 100644
--- a/os/rt/include/chsys.h
+++ b/os/rt/include/chsys.h
@@ -145,35 +145,38 @@
 /**
  * @brief   Realtime counter cycles to seconds.
  * @details Converts from realtime counter cycles number to seconds.
+ * @note    The result is rounded up to the next second boundary.
  *
  * @param[in] n         number of cycles
  * @return              The number of seconds.
  *
  * @api
  */
-#define RTC2S(n) (rtcnt_t)(CH_CFG_RTC_FREQUENCY / (freq))
+#define RTC2S(n) ((((n) - 1UL) / CH_CFG_RTC_FREQUENCY) + 1UL)
 
 /**
  * @brief   Realtime counter cycles to milliseconds.
  * @details Converts from realtime counter cycles number to milliseconds.
+ * @note    The result is rounded up to the next millisecond boundary.
  *
  * @param[in] n         number of cycles
  * @return              The number of milliseconds.
  *
  * @api
  */
-#define RTC2MS(n) ((n) / (CH_CFG_RTC_FREQUENCY / 1000UL))
+#define RTC2MS(n) ((((n) - 1UL) / (CH_CFG_RTC_FREQUENCY / 1000UL)) + 1UL)
 
 /**
  * @brief   Realtime counter cycles to microseconds.
  * @details Converts from realtime counter cycles number to microseconds.
+ * @note    The result is rounded up to the next microsecond boundary.
  *
  * @param[in] n         number of cycles
  * @return              The number of microseconds.
  *
  * @api
  */
-#define RTC2US(n) ((n) / (CH_CFG_RTC_FREQUENCY / 1000000UL))
+#define RTC2US(n) ((((n) - 1UL) / (CH_CFG_RTC_FREQUENCY / 1000000UL)) + 1UL)
 /** @} */
 
 /**
diff --git a/os/rt/include/chvt.h b/os/rt/include/chvt.h
index ea84df9fd..35d9986c0 100644
--- a/os/rt/include/chvt.h
+++ b/os/rt/include/chvt.h
@@ -160,6 +160,42 @@ struct virtual_timer {
 #define US2ST(usec)                                                         \
   ((systime_t)(((((uint32_t)(usec)) *                                       \
                  ((uint32_t)CH_CFG_ST_FREQUENCY) - 1UL) / 1000000UL) + 1UL))
+
+/**
+ * @brief   System ticks to seconds.
+ * @details Converts from system ticks number to seconds.
+ * @note    The result is rounded up to the next second boundary.
+ *
+ * @param[in] n         number of system ticks
+ * @return              The number of seconds.
+ *
+ * @api
+ */
+#define ST2S(n) ((((n) - 1UL) / CH_CFG_ST_FREQUENCY) + 1UL)
+
+/**
+ * @brief   System ticks to milliseconds.
+ * @details Converts from system ticks number to milliseconds.
+ * @note    The result is rounded up to the next millisecond boundary.
+ *
+ * @param[in] n         number of system ticks
+ * @return              The number of milliseconds.
+ *
+ * @api
+ */
+#define ST2MS(n) ((((n) - 1UL) / (CH_CFG_ST_FREQUENCY / 1000UL)) + 1UL)
+
+/**
+ * @brief   System ticks to microseconds.
+ * @details Converts from system ticks number to microseconds.
+ * @note    The result is rounded up to the next microsecond boundary.
+ *
+ * @param[in] n         number of system ticks
+ * @return              The number of microseconds.
+ *
+ * @api
+ */
+#define ST2US(n) ((((n) - 1UL) / (CH_CFG_ST_FREQUENCY / 1000000UL)) + 1UL)
 /** @} */
 
 /*===========================================================================*/