We have custom board based on imx6ul evk which has rtc. The problem we are facing is that system clock is slowing down over a time very fast(board is running during this period) even thought rtc clock is running fine. I updated time in yocto to current time using date command and then updated hardware clock to match system clock using hwclock -w command. Now as the board is running for next 2 minutes we found that system clock slows down and falls behind but hardware clock is working fine. We found that for every 10 seconds system clock updates only about 2-3 seconds. What can be the reason for this? We found no such problem in imxul evk board.