boot/config.txt
#RTC config
dtparam=i2c_arm=on
dtoverlay=i2c-rtc,ds3231
apt-get purge fake-hwclock // optional
Comment out
/lib/udev/hwclock-set
#if [ -e /run/systemd/system ] ; then
# exit 0
#fi
boot/config.txt
#RTC config
dtparam=i2c_arm=on
dtoverlay=i2c-rtc,ds3231
apt-get purge fake-hwclock // optional
Comment out
/lib/udev/hwclock-set
#if [ -e /run/systemd/system ] ; then
# exit 0
#fi