I have set up the external RTC as per instructions.
As the system comes up with no net connection initially (takes time for the mobile modem to connect), I would expect the system clock to get set from RTC as documented (by systemd.timedatectl), but it does not:
ubuntu@tegra-ubuntu:~$ date
Sat Jan 1 02:12:44 IST 2000
ubuntu@tegra-ubuntu:~$ sudo timedatectl
[sudo] password for ubuntu:
Local time: Sat 2000-01-01 02:12:50 IST
Universal time: Sat 2000-01-01 00:12:50 UTC
RTC time: Thu 2017-12-21 15:02:18
Timezone: Asia/Jerusalem (IST, +0200)
NTP enabled: yes
NTP synchronized: yes
RTC in local TZ: no
DST active: no
Last DST change: DST ended at
Fri 1999-09-03 01:59:59 IDT
Fri 1999-09-03 01:00:00 IST
Next DST change: DST begins (the clock jumps one hour forward) at
Fri 2000-04-14 01:59:59 IST
Fri 2000-04-14 03:00:00 IDT
ubuntu@tegra-ubuntu:~$ dmesg | grep -i rtc
[ 0.516409] +V1.05_RTC: 1000 mV at 150 mA
[ 4.673638] as3722-rtc as3722-rtc.1: rtc core: registered as3722 as rtc0
[ 4.673647] as3722-rtc as3722-rtc.1: RTC interrupt 449
[ 4.748028] rtc-ds1307 0-0068: rtc core: registered m41t0 as rtc1
[ 4.748499] tegra_rtc tegra_rtc: rtc core: registered tegra_rtc as rtc2
[ 4.748536] tegra_rtc tegra_rtc: Tegra internal Real Time Clock
[ 7.668157] as3722-rtc as3722-rtc.1: setting system clock to 2000-01-01 00:10:01 UTC (946685401)
ubuntu@tegra-ubuntu:~$ cat /etc/udev/rules.d/99-rtc1.rules
KERNEL=="rtc1", SUBSYSTEM=="rtc", DRIVER=="", ATTR{name}=="m41t0", SYMLINK="rtc", MODE="0666"
ubuntu@tegra-ubuntu:~$
How can I get the system date to update from the RTC at start up?