Jetson nano reboot suddenly enter APX mode, no access the ubuntu

Hi, nivida
My carrier board is equipped with EMMC Nano,the system in ssd. When I reboot my board, the nx suddenly enert APX mode, it is look like my system is died,and the debug serial is no output.I try a lot of different way to make my system run,but it is not work.The Nano still in APX mode .
could you help to check which the problem may be?

There is no update from you for a period, assuming this is not an issue any more.
Hence we are closing this topic. If need further support, please open a new one.

Maybe you should read your comment first. First you file topic in Nano forum, you said you are using nano. And later you said NX enter APX mode, what is the exact platofrm?

Also, are you sure your debug serial ever dumping a log before? If so, could you share that so that I can make sure that is really a uart serial log?