diff --git a/os/hal/platforms/STM32/GPIOv2/pal_lld.h b/os/hal/platforms/STM32/GPIOv2/pal_lld.h
index 6c799c14c..a73f80c7a 100644
--- a/os/hal/platforms/STM32/GPIOv2/pal_lld.h
+++ b/os/hal/platforms/STM32/GPIOv2/pal_lld.h
@@ -135,13 +135,7 @@ typedef struct {
   volatile uint32_t     PUPDR;
   volatile uint32_t     IDR;
   volatile uint32_t     ODR;
-  volatile union {
-    uint32_t            W;
-    struct {
-      uint16_t          set;
-      uint16_t          clear;
-    } H;
-  } BSRR;
+  volatile uint32_t     BSRR;
   volatile uint32_t     LCKR;
   volatile uint32_t     AFRL;
   volatile uint32_t     AFRH;
@@ -375,7 +369,7 @@ typedef GPIO_TypeDef * ioportid_t;
  *
  * @notapi
  */
-#define pal_lld_setport(port, bits) ((port)->BSRR.H.set = (uint16_t)(bits))
+#define pal_lld_setport(port, bits) ((port)->BSRR = (uint32_t)(bits))
 
 /**
  * @brief   Clears a bits mask on a I/O port.
@@ -392,7 +386,7 @@ typedef GPIO_TypeDef * ioportid_t;
  *
  * @notapi
  */
-#define pal_lld_clearport(port, bits) ((port)->BSRR.H.clear = (uint16_t)(bits))
+#define pal_lld_clearport(port, bits) ((port)->BSRR = (uint32_t)(bits) << 16)
 
 /**
  * @brief   Writes a group of bits.
@@ -413,8 +407,8 @@ typedef GPIO_TypeDef * ioportid_t;
  * @notapi
  */
 #define pal_lld_writegroup(port, mask, offset, bits)                        \
-  ((port)->BSRR.W = ((~(bits) & (mask)) << (16 + (offset))) |               \
-                     (((bits) & (mask)) << (offset)))
+  ((port)->BSRR = ((~(bits) & (mask)) << (16 + (offset))) |                 \
+                   (((bits) & (mask)) << (offset)))
 
 /**
  * @brief   Pads group mode setup.
diff --git a/testhal/STM32F1xx/GPT/main.c b/testhal/STM32F1xx/GPT/main.c
index 09b3ba9b3..e3e0797f8 100644
--- a/testhal/STM32F1xx/GPT/main.c
+++ b/testhal/STM32F1xx/GPT/main.c
@@ -86,8 +86,10 @@ int main(void) {
    * five seconds.
    */
   while (TRUE) {
+    gptStopTimer(&GPTD1);
     gptStartContinuous(&GPTD1, 5000);
     chThdSleepMilliseconds(5000);
+    gptStopTimer(&GPTD1);
     gptStartContinuous(&GPTD1, 2500);
     chThdSleepMilliseconds(5000);
   }
diff --git a/testhal/STM32L1xx/GPT/Makefile b/testhal/STM32L1xx/GPT/Makefile
index 9209b441d..10a6ed0e8 100644
--- a/testhal/STM32L1xx/GPT/Makefile
+++ b/testhal/STM32L1xx/GPT/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16
+  USE_OPT = -O0 -ggdb -fomit-frame-pointer -falign-functions=16
 endif
 
 # C++ specific options here (added to USE_OPT).
diff --git a/testhal/STM32L1xx/GPT/main.c b/testhal/STM32L1xx/GPT/main.c
index 90e06879a..49247bac6 100644
--- a/testhal/STM32L1xx/GPT/main.c
+++ b/testhal/STM32L1xx/GPT/main.c
@@ -86,8 +86,12 @@ int main(void) {
    * five seconds.
    */
   while (TRUE) {
+    palSetPad(GPIOB, GPIOB_LED3);
+    gptStopTimer(&GPTD2);
     gptStartContinuous(&GPTD2, 5000);
     chThdSleepMilliseconds(5000);
+    palClearPad(GPIOB, GPIOB_LED3);
+    gptStopTimer(&GPTD2);
     gptStartContinuous(&GPTD2, 2500);
     chThdSleepMilliseconds(5000);
   }