diff --git a/os/hal/ports/STM32/LLD/RTCv1/hal_rtc_lld.c b/os/hal/ports/STM32/LLD/RTCv1/hal_rtc_lld.c
index 030918c2d..502ee5b31 100644
--- a/os/hal/ports/STM32/LLD/RTCv1/hal_rtc_lld.c
+++ b/os/hal/ports/STM32/LLD/RTCv1/hal_rtc_lld.c
@@ -130,14 +130,15 @@ static void rtc_decode(uint32_t tv_sec,
                        RTCDateTime *timespec) {
   struct tm tim;
   struct tm *t;
+  const time_t time = tv_sec;	/* Copy with implicit type conversion.*/
 
   /* If the conversion is successful the function returns a pointer
      to the object the result was written into.*/
 #if defined(__GNUC__) || defined(__CC_ARM)
-  t = localtime_r((time_t *)&(tv_sec), &tim);
+  t = localtime_r(&time, &tim);
   osalDbgAssert(t != NULL, "conversion failed");
 #else
-  t = localtime(&tv_sec);
+  t = localtime(&time);
   memcpy(&tim, t, sizeof(struct tm));
 #endif
 
diff --git a/readme.txt b/readme.txt
index ae5bbe5c5..4f504905e 100644
--- a/readme.txt
+++ b/readme.txt
@@ -141,6 +141,8 @@
 - EX:  Updated LIS302DL to 1.1.0 (backported to 18.2.1).
 - EX:  Updated LPS25H to 1.1.0 (backported to 18.2.1).
 - EX:  Updated LSM303DLHC to 1.1.0 (backported to 18.2.1).
+- HAL: Fixed problem with STM32 RTCv1 and GCC7 compiler (bug #964)(backported
+       to 18.2.2 and 17.6.5).
 - HAL: Fixed invalid timeout calculation in hal_buffers (bug #963)(backported
        to 18.2.2 and 17.6.5).
 - RT:  Fixed invalid parameter in CH_CFG_SYSTEM_INIT_HOOK hook macro