diff --git a/os/hal/platforms/STM32/icu_lld.c b/os/hal/platforms/STM32/icu_lld.c
index 0f8bc4bc7..f9305d786 100644
--- a/os/hal/platforms/STM32/icu_lld.c
+++ b/os/hal/platforms/STM32/icu_lld.c
@@ -106,8 +106,9 @@ ICUDriver ICUD8;
 static void icu_lld_serve_interrupt(ICUDriver *icup) {
   uint16_t sr;
 
-  sr = icup->tim->SR & icup->tim->DIER;
-  icup->tim->SR = 0;
+  sr  = icup->tim->SR;
+  sr &= icup->tim->DIER;
+  icup->tim->SR = ~sr;
   if ((sr & TIM_SR_CC1IF) != 0)
     _icu_isr_invoke_period_cb(icup);
   if ((sr & TIM_SR_CC2IF) != 0)
diff --git a/readme.txt b/readme.txt
index 22cbcefcd..27e4f5866 100644
--- a/readme.txt
+++ b/readme.txt
@@ -79,6 +79,7 @@
 *****************************************************************************
 
 *** 2.4.3 ***
+- FIX: Fixed warning in STM32 ICU driver using IAR compiler (bug 3598177).
 - FIX: Fixed typo in chOQGetEmptyI() macro (bug 3595910).
 - FIX: Fixed possible false detect of loaded prescaler in RTCv1 driver (bug 
   3595489).