关于Zynq平台运行SDK程序的错误解决方法 launching, Hardware, running, error, ERROR

按照书上的教程，写了一个流水灯的例子。先Program FPGA，然后Run as -> Launch on Hardware，就报下面错误：
16:22:28 ERROR        : Unexpected error while launching program.
java.lang.RuntimeException: Error while running ps7_init method.
Cannot Read from target
MMU page translation fault
at com.xilinx.sdk.targetmanager.internal.TM.run_ps7_init(TM.java:1069)
at com.xilinx.sdk.debug.core.XilinxAppLaunchConfigurationDelegate.runTargetSetup(XilinxAppLaunchConfigurationDelegate.java:403)
at com.xilinx.sdk.debug.core.XilinxAppLaunchConfigurationDelegate.runApplication(XilinxAppLaunchConfigurationDelegate.java:505)
at com.xilinx.sdk.debug.core.XilinxAppLaunchConfigurationDelegate.launch(XilinxAppLaunchConfigurationDelegate.java:254)
解决方法是：
打开串口助手，Reset板子，启动到u-boot的时候，按任意键，不要让系统进入Linux，只停留在uboot阶段。如下，
U-Boot 2012.04.01-dirty (Jun 24 2013 - 10:59:35)
DRAM: 512 MiB
WARNING: Caches not enabled
MMC: SDHCI: 0
Using default environment
In: serial
Out: serial
Err: serial
Net: zynq_gem