Dear sir,
in my designed application IMX6ULL-521MB SOM is using.
In one particular PCB board SOM is not booting completely .
My observations in booting log file 
1.booting stuck at the last line is [ 2.612278] —[ end trace 94071b8f4540425d ]— while initializing below
[ 2.432063] WARNING: CPU: 0 PID: 7 at drivers/clk/clk.c:816 clk_core_unprepare+0xec/0x148
[ 2.440312] sai2 already unprepared
[ 2.443820] Modules linked in:
[ 2.446904] CPU: 0 PID: 7 Comm: kworker/u2:0 Tainted: G W 5.4.115-5.1.0-devel+git.a08f3c7add53 #1
2.Before the above point end trace is coming for below
[ 2.243318] WARNING: CPU: 0 PID: 7 at drivers/clk/clk.c:958 clk_core_disable+0xc4/0xcc
[ 2.251267] sai2 already disabled
[ 2.254599] Modules linked in:
[ 2.257683] CPU: 0 PID: 7 Comm: kworker/u2:0 Not tainted 5.4.115-5.1.0-devel+git.a08f3c7add53 #1
at this time also line as [ 2.422606] —[ end trace 94071b8f4540425c ]—