Rtc sync issue after boot

General
1

Hi Vicharak team,

I am using a **Vicharak Axon board ** and I added the RTC battery as mentioned in the Axon RTC documentation.

I used a THIS RTC BATTERY. After connecting it, I set the system time and synced it to RTC using:

sudo hwclock --systohc
sudo hwclock --show

The RTC time shows correctly before reboot/power-off. But after rebooting / removing power and booting again after some time, I am not getting the saved RTC time back properly. I have also configured this to update rtc clock periodically. :

sudo hwclock --systohc
sudo hwclock -r
apt install cron
crontab -e

*/5 * * * * hwclock --systohc

Can you please help confirm whether this is a battery issue, RTC configuration issue, or if I am missing any step?

Logs/commands output:


root@kapidhwaj:/home/admin# dmesg | grep -i rtc
[   17.861608] rtc-hym8563 0-0051: rtc information is valid
[   17.868504] rtc-hym8563 0-0051: registered as rtc0
[   17.869502] rtc-hym8563 0-0051: setting system clock to 2000-01-01T00:00:17 UTC (946684817)
[   18.980668] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_disable] Crtc atomic disable vp0
[   19.030557] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_disable] *ERROR* unexpected power on pd6
[   19.030571] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_disable] *ERROR* unexpected power on pd5
[   19.188747] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_disable] wait for vp0 dsp_hold timeout
[   19.197711] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_enable] Update mode to 1368x768p60, type: 11(if:HDMI0, flag:0x0) for vp0 dclk: 85500000
[   19.198268] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_enable] dclk_out0 div: 0 dclk_core0 div: 2
[   19.198645] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_enable] set dclk_vop0 to 85500000, get 85500000
[   26.996363] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_disable] Crtc atomic disable vp0
[   27.016388] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_disable] *ERROR* unexpected power on pd6
[   27.016409] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_disable] *ERROR* unexpected power on pd5
[   27.100666] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_enable] Update mode to 1368x768p60, type: 11(if:HDMI0, flag:0x0) for vp0 dclk: 85500000
[   27.101104] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_enable] dclk_out0 div: 0 dclk_core0 div: 2
[   27.101126] rockchip-vop2 fdd90000.vop: [drm:vop2_crtc_atomic_enable] set dclk_vop0 to 85500000, get 85500000
root@kapidhwaj:/home/admin# dmesg | grep -i 8563
[   17.861608] rtc-hym8563 0-0051: rtc information is valid
[   17.868504] rtc-hym8563 0-0051: registered as rtc0
[   17.869502] rtc-hym8563 0-0051: setting system clock to 2000-01-01T00:00:17 UTC (946684817)
[   18.078563] mpp_rkvdec2 fdc38100.rkvdec-core: [139, 180224]
root@kapidhwaj:/home/admin# sudo hwclock --show
2026-03-13 23:21:53.831018+05:30
root@kapidhwaj:/home/admin# timedatectl
               Local time: Wed 2026-06-03 15:25:43 IST
           Universal time: Wed 2026-06-03 09:55:43 UTC
                 RTC time: Fri 2026-03-13 17:51:59
                Time zone: Asia/Kolkata (IST, +0530)
System clock synchronized: no
              NTP service: n/a
          RTC in local TZ: no
root@kapidhwaj:/home/admin#

Setup Images :
unnamed
unnamed

Thanks.

2

Axon RTC Documentation

Mostly it works fine, as it seem looking at logs.
Try changing cell for surity as well.

4

still same. time is not updating after booting some time. it’s going back to 13 march even though i set it today’s date

5

just to add - i am using 25mah rechargeable Battery.

6
  1. Connect the Axon board to the internet and wait a few moments for the system time to automatically sync with the network.
  2. Run the RTC configuration command to save the synchronized network time directly to the hardware clock. Remove Axon from any internet connectivity.
  3. Power off the board completely, then turn it back on to verify if the correct time persists after booting.
7

Yepp Did Exacly same. but still happened

8

can you please give me any suggestions or guidelines on how to debug this. or possible reasons for this ?

9

Remove the configuration that you have done using crontab.

And follow the same procedure that I have mentioned.

As mentioned It should work, it may have battery issue as well.

Could you give output of below command :

sudo i2cdetect -y 0
10

root@kapidhwaj:/opt/nvr/compose# sudo i2cdetect -y 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – – – – – – – –
10: – – – – – – – – – – – – – – – –
20: – – – – – – – – – – – – – – – –
30: – – – – – – – – – – – – – – – –
40: – – UU UU – – – – – – – – – – – –
50: – UU – – – – – – – – – – – – – –
60: – – – – – – – – – – – – – – – –
70: – – – – – – – –
root@kapidhwaj:/opt/nvr/compose#

11

i2c address is probed through 51 address.
Could you try with another Battery Cell !?