案例题目： HZ49A65 卡在开机画面然后重启
关联产品： HZ49A65
机芯方案： Hi3751V5510
故障现象： 卡在开机画面然后重启
故障原因分析： 卡在开机画面重启，首先测量电源管理电路DC-DC,LDO有无异常，如果无异常下一步通过打印信息进行故障判断，
检修过程： 卡在开机画面重启，首先测量电源管理电路DC-DC,LDO未发现异常，连接工装部分打印信息如下：
[ 1.857896] init: couldn’t write 1632 to /dev/cpuset/foreground/tasks: No such file or directory
[ 2.054082] init: couldn’t write 1606 to /sys/fs/cgroup/stune/foreground/tasks: No such file or directory
[ 2.072091] init: couldn’t write 1612 to /sys/fs/cgroup/stune/foreground/tasks: No such file or directory
[ 2.086197] init: couldn’t write 1610 to /dev/cpuset/system-background/tasks: No such file or directory
[ 3.748736] init: Service toltech does not have a SELinux domain defined.
[ 5.721492] pgd = ffffffc073728000
[ 5.724883] [0000009c] *pgd=0000000000000000, *pud=0000000000000000
[ 8.811371] init: couldn’t write 1991 to /sys/fs/cgroup/stune/foreground/tasks: No such file or directory
[ 8.814189] init: couldn’t write 1992 to /dev/stune/foreground/tasks: No such file or directory
[ 8.839500] init: cannot find ‘/system/bin/teecd’ (No such file or directory), disabling ‘teecd’
[ 8.908066] init: cannot setexeccon(‘u:r:logwrapper:s0’): Invalid argument
<IAMREADY>
更换N60的DDR K4A8G165WB-BCRC 后故障排除。
故障板号： RSAG7.820.7941
故障元件： K4A8G165WB-BCRC