Hi igorpadykov,
Thanks for your reponse, I don't think that casues by power supplies. because it works well with sd card boot. and if I use vi to open a file, then input something to the file, and then input "wq" to save and exit, the target will hang too without inserting any cables.
btw, if replace kernel with linux-imx-4.1.15-r0, can not find the issue, so I think may by it's a bug with linux-imx-4.9.88-r0. But I don't know how to debug this.
Thank you!