diff --git a/os/hal/src/rtc.c b/os/hal/src/rtc.c
index 785b07721..b062184e6 100644
--- a/os/hal/src/rtc.c
+++ b/os/hal/src/rtc.c
@@ -226,6 +226,7 @@ void rtcConvertDateTimeToStructTm(const RTCDateTime *timespec,
   timp->tm_mon   = (int)timespec->month - 1;
   timp->tm_mday  = (int)timespec->day;
   timp->tm_isdst = (int)timespec->dstflag;
+  timp->tm_wday  = (int)timespec->dayofweek - 1;
 
   sec = (int)timespec->millisecond / 1000;
   timp->tm_hour = sec / 3600;
diff --git a/readme.txt b/readme.txt
index 215858285..2606224d1 100644
--- a/readme.txt
+++ b/readme.txt
@@ -133,6 +133,8 @@
        STM32F098xx devices.
 - HAL: Fixed differences in STM32F3 ADC macro definitions (bug #665)
        (backported to 3.0.3).
+- HAL: Fixed RTC module loses day of week when converting (bug #664)
+       (backported to 3.0.3).
 - HAL: Fixed invalid class type for sdPutWouldBlock() and sdGetWouldBlock()
        functions (bug #659)(backported to 3.0.3 and 2.6.10).
 - HAL: Fixed STM32F0xx HAL missing MCOPRE support (bug #658).