I have done 50 units of production with my custom hardware and some of the boards are working really well and some are not (10 are working out of 50, others are getting kernel crash). And also previously we did 50 units of production with the same design and out of them 30 boards worked really well. So now we need to isolate the problem for this random issue and need to identify whether it is manufacturing issue or another design issue before we go for mass production.
Processor - iMAX6Q
Presently I'm using NXP tools stress test, Stress app test and VTOS (KOZIO) memory verification and stress test tools for memory fault isolation process. But I couldn't identify any issue in memory layout by using those tools. All the tests passed. I have done DDR memory calibration for my imx6q custom hardware design using NXP stress tester version 2.9 and got proper and reliable read,write,dqs gating values for DDR memory. And I updated u-boot configs according to those values.
1) Could you please go through with the attached files of NXP calibration results ? Can you identify any problem with those calibrations ?
2) According to your experience what could be the reason for some boards are working and some are not in same production batch ?