root@odroid:~# systemctl enable hwrtc
    root@odroid:~# reboot
    .
    .
    root@odroid:~# systemctl status hwrtc
     ● hwrtc.service - Synchronise System clock to hardware RTC
     Loaded: loaded (/lib/systemd/system/hwrtc.service; enabled; vendor preset: enabled)
     Active: active (exited) since Fri 2021-01-15 11:23:08 KST; 12min ago
     Main PID: 2116 (code=exited, status=0/SUCCESS)
     Tasks: 0 (limit: 3839)
     Memory: 0B
     CGroup: /system.slice/hwrtc.service
     Jan 15 11:23:08 odroid hwclock[2116]: ioctl(4, RTC_UIE_ON, 0): Invalid argument
     Jan 15 11:23:08 odroid hwclock[2116]: Waiting in loop for time from /dev/rtc0 to change
     Jan 15 11:23:08 odroid hwclock[2116]: ...got clock tick
     Jan 15 11:23:08 odroid hwclock[2116]: Time read from Hardware Clock: 2021/01/15 02:23:08
     Jan 15 11:23:08 odroid hwclock[2116]: Hw clock time : 2021/01/15 02:23:08 = 1610677388 seconds since 1969
     Jan 15 11:23:08 odroid hwclock[2116]: Time since last adjustment is 1610677388 seconds
     Jan 15 11:23:08 odroid hwclock[2116]: Calculated Hardware Clock drift is 0.000000 seconds
     Jan 15 11:23:08 odroid hwclock[2116]: Calling settimeofday(NULL, 0) to lock the warp_clock function.
     Jan 15 11:23:08 odroid hwclock[2116]: Calling settimeofday(NULL, -540) to set the kernel timezone.
     Jan 15 11:23:08 odroid hwclock[2116]: Calling settimeofday(1610677388.000000, NULL) to set the System time.