For the reComputer Industrial J4012 there is already an RTC installed on the board, together with JetPack 6.0 this should work without any extra configuration. However, sometimes after a reboot (especially if the power cable was disconnected) synchronization with the RTC fails:
$ sudo hwclock -v
hwclock from util-linux 2.37.2
System Time: 1751974806.521236
Trying to open: /dev/rtc0
Using the rtc interface to the clock.
Last drift adjustment done at 1751904326 seconds after 1969
Last calibration done at 1751904326 seconds after 1969
Hardware clock is on UTC time
Assuming hardware clock is kept in UTC time.
Waiting for clock tick...
hwclock: select() to /dev/rtc0 to wait for clock tick timed out
...synchronization failed
This persists even after waiting for five minutes. What could be the cause of this and can this be fixed? The battery seems to be properly installed and this issue does not always occur.
So Captain obvious here, LOL, what about the battery, is it fresh?
I have seen this Power question thing on here before too. Give it a good visual inspection, be sure no loose mobo screws also, Maybe reseat the battery. I think the grounding needs to be solid too.
Thank you for your reply @PJ_Glasso battery is definitely fresh. We have this issue occur with pretty much all the j4012 devices here. Battery seems pretty tightly in its place, also reseating the battery for each device we get in is sadly unfeasible.
We’ve now realized that the RTC in general seems to reset back to 1970, or rather, the counter goes back to zero. Turning of the NTP service thus results in our devices consistently resetting.
Thanks for that , Sounds like an “undocumented enhancement” or otherwise known as a BUG…
Great job sleuthing it out , even if it’s luck, well bad anyway.
“C’mon man” is what I’m thinking to the seeedeneer in charge of this Device image… RTC really ?I know some folks are on summer holiday there, so send an e-mail to support , so it’s on the radar.
We attempted to use RTC for automatic clock synchronization under JP6.1. The video is as follows:
Step 1: Open a terminal window, and execute the below command to check the hardware clock time
sudo hwclock
Step 2: Change the hardware clock time to the current system clock time by entering the below command
sudo hwclock --systohc
Step 3: Remove any Ethernet cables connected to make sure it will not grab the time from the internet and reboot the board
sudo reboot
Finally, the date/time remains unchanged even after the device was powered off.
Since the reComputer industrial requires specific driver files to operate peripherals properly, you must use the image file we provide for it to function correctly. Maybe you can try the RTC functionality again using the image we provided.
Hi @Seeed_Seraphina thank you for checking. Would you mind trying again, but leaving the device without power for a couple of hours? If I reboot the device relatively fast, there is no issue, however, if there is no power supply attached for a longer period of time, the RTC seems to reset:
Local time: do 2025-08-28 09:15:57 UTC
Universal time: do 2025-08-28 09:15:57 UTC
RTC time: do 1970-01-01 00:00:45
Time zone: Etc/UTC (UTC, +0000)
System clock synchronized: no
NTP service: active
RTC in local TZ: no
The software clock jumps back to the last time there was a sync over NTP.
PJ 
?I know some folks are on summer holiday there, so send an e-mail to support , so it’s on the radar.
