新做的imx6核心板一开始能烧系统成功，过一段时间后再烧系统就卡在clear u-boot这一步，但之前烧录的系统和程序还能正常运行，这是什么原因?
which i.MX6 chip are you using?
which tool are you using to program the board?
is there any error message?
