rockpro 64 does not boot up automatically after software reboot

[rahulsharma]

So not able to decide if it is hardware error or OS error.

Rahul, you still didn't said have you tried to connect an RTC battery?

Hi,
No i didn't use any RTC battery. 
I think this will be just for system clock purpose. Thus it will not be used as power bacup for the whole rockpro.
I am talking about the main power fluctuation. 

Let me clarify on my points above-
Requirement-
Device is needed to be used for 24x7 working for on eof my project.

Issue -
Device stops working after few days of working.

Environmental condition-
Power(12V 5A) is getting from SMPS but sometimes main power goes and comes so power shutdown is there unexpectedly and suddenly. And its frequency is not same such as 1-5 times in a day.

Observtions-
Devices were not booting.

Debugging steps-
Few devices work again after reflashing of same Ubuntu18.04 LXDE image .
Few devices boot but with Android OS not with Linux OS.
Few devices even does not boot at all.

So i was predicting if it happened just because of power or image is no stable or something else. Still not able to find main root cause

Note-
I was also thinking for a module or circuit so that can be used for few mins to graceful shutdown to device when main 12V dc power goes.

Thanks.