UbuntuMATE 15.10 reset RTC chip date & time during bootup

I have an RPi 2 B device with an RTC chip DS3231 hooked up on its GPIO pins, and am activating the RTC by adding “dtoverlay=i2c-rtc,ds3231" at the end of the “/boot/config.txt” file.

The corresponding “/dev/rtc0” device file gets created properly and I can query the date and time values from the RTC chip using the “hwclock” and “timedatectl” commands.

However, it happens that after the reboot of the device, I’m getting readings from the RTC chip to be of an older date and time if “fake-hwcock” is activated, or am getting 1 Jan 1970 if I have deinstalled the “fake-hwclock”.

It seems that the new release of UbuntuMATE 15.10 is resetting the date and time settings upon a reboot as per above. Using Debian Jessie, everything seems to be working fine.

I have posted this issue at the Raspberry Pi Forum: UbuntuMATE 15.10 keeps the time of last shutdown in RTC chip, however the topic seems more related in the way how “Systemd” is processing RTC date and time during boot up.

Please have a look in my post in the Raspberry Pi forums first, and I can take the discussions further within this forum.


OK, seems that I did not get any feedback on my original post :frowning:

So I went ahead and came up myself with an approach and solution as descibed in my post in the Raspberry Pi forum.

Please have a look there, and hope this helps to overcome the same challanges I have had :wink:

For those, who cannot read the posts in the Raspberry Pi forum, I’m posting the same little turorial on how to setup the mechanism to correctly read the date and time from an RTC chip hooked up on the GPIO pins of your RPi device and keep it syncronised with NTP.

I’ve tested this on Debian Jessie and UbuntuMATE 15.10 and seems to be working fine on my devices.

1st approach:

If sticking to the classical “services” start-up mechanism as it comes today preinstalled, then the file “/lib/udev/hwclock-set” can be modified with the following contents:


File: /lib/udev/hwclock-set

Called by: /lib/udev/rules.d/85-hwclock.rules

Reset the System Clock to UTC if the hardware clock from which it

was copied by the kernel was in localtime.


if [ -e /run/udev/hwclock-set ]; then
exit 0

if [ -f /etc/default/rcS ] ; then
. /etc/default/rcS

These defaults are user-overridable in /etc/default/hwclock


if [ -f /etc/default/hwclock ] ; then
. /etc/default/hwclock

check if RTC chip is already discovered with “dtoverlay=i2c-rtc,ds3231” in /boot/config.txt

if [ ! “cat /proc/modules | grep rtc | grep -i live” ]; then

remove module from “blacklist.conf” if existant

[ -f /etc/modprobe.d/$BLACKLIST ] && sed -n -i ‘s/blacklist i2c-bcm2708/#blacklist i2c-bcm2708/’ /etc/modprobe.d/$BLACKLIST

load i2c kernel modules if not already loaded with “dtparam=i2c” in /boot/config.txt

[ “cat /proc/modules | grep i2c_bcm2708 | grep -i live” ] || modprobe -q i2c-bcm2708

iterate over every i2c bus as we’re supporting Raspberry Pi rev. 1 and 2 (different I2C busses on GPIO header!)

[ “cat /proc/modules | grep i2c_bcm2708 | grep -i live” ] && for i in ls -1 /sys/class/i2c-adapter; do
if [ $i ]; then
[ -w /sys/class/i2c-adapter/$i/new_device ] && echo ds3231 0x68 >> /sys/class/i2c-adapter/$i/new_device

wait at least 1 second time (1 clock tick) to ensure device file creation

sleep 1
if [ -e /dev/$HCTOSYS_DEVICE ]; then

 if [ yes = "$BADYEAR" ]; then
   /sbin/hwclock --rtc=$dev --hctosys --badyear
   /sbin/hwclock --rtc=$dev --hctosys

[ -w /sys/class/i2c-adapter/$i/delete_device ] && echo 0x68 >> /sys/class/i2c-adapter/$i/delete_device

Note ‘touch’ may not be available in initramfs


See the Debian Bug Report # 764552 on further details why the contents of the file “/lib/udev/hwclock-set” needs to be modified.

2nd approach:

If you like to take another approach using the “systemd” mechanism, then follow these steps:

Edit the file “/boot/config.txt” and add a similar line like “dtoverlay=i2c-rtc,ds3231” to instruct the kernel to create the device file for the RTC chip DS3231.

On the shell prompt and with “root” privileges, type the following commands:

systemctl stop hwclock.sh fake-hwclock ntp systemctl disable hwclock.sh fake-hwclock ntp systemctl mask hwclock.sh fake-hwclock ntp
Create a file “/etc/systemd/system/hwclock-sync.service” with the following contents:

Description=Time Synchronization from RTC Source

ExecStart=/sbin/hwclock -s

Edit the file “/etc/rc.local” and add the following line:

[ ! -e /var/lib/systemd/clock -a "`systemctl is-active systemd-timesyncd | grep -i active`" ] && timedatectl set-ntp 1 > /dev/null 2>&1

Create or edit the file “/etc/systemd/timesyncd.conf” with the following contents:

[Time] NTP=0.europe.pool.ntp.org 1.europe.pool.ntp.org 2.europe.pool.ntp.org 3.europe.pool.ntp.org FallbackNTP=0.europe.pool.ntp.org 1.europe.pool.ntp.org 2.europe.pool.ntp.org 3.europe.pool.ntp.org
Back at the shell prompt, type the following command to enable the automatic start-up during boot of the services for the time synchronisation from the RTC chip and also from an NTP source if connected to the Internet:

systemctl enable hwclock-sync systemd-timesyncd

The following command will manually startup the described services from the shell prompt:

systemctl start hwclock-sync systemd-timesyncd

With this approach, we leave it up to “systemd” to start up the relevant services for date and time synchronisation from an RTC source and from an NTP source, the “timesyncd” service will take care to synchronise the RTC chip with the date and time settings obtained from NTP.

You can verify this by executing the following command on the shell prompt:


The output from this command shall be similar to the following:

Local time: Wed 2015-11-18 09:44:46 CET Universal time: Wed 2015-11-18 08:44:46 UTC RTC time: Wed 2015-11-18 08:44:46 Time zone: … (CET, +0100) Network time on: yes NTP synchronized: yes RTC in local TZ: no
The legacy services “fake-hwclock” and “ntp” can be deinstalled, since no longer required :wink:

Hope this helps :blush:


@carriba Thank you for your detailed post :smiley:
We will have a look at this issue and take these steps into consideration…

Just flashed a new RPi 2 B device with UbuntuMATE 15.10.1, have applied the sames changes as described under section “2nd approach” above and can confirm to be working just fine with a RTC chip DS3231 hooked up on the GPIO pins.

The 2nd above described approach also works without an RTC chip hooked up on the GPIO pins. Using only the “timesyncd” daemon, system time can be synchronised from Internet time sources.