【求助】请问为什么我的开发板每次上电的时候要在终端下选择重启系统才可以运行？

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如题，我用的是TQ2440开发板，把光盘里面的内核移植到开发板上面去之后，每次给开发板上电都没有反映，只有打开超级终端并且复位开发板之后才会在终端下面出现一些引导信息如：
[1] Download u-boot or STEPLDR.nb1 or other bootloader to Nand Flash
[2] Download Eboot (eboot.nb0) to Nand Flash
[3] Download Linux Kernel (zImage.bin) to Nand Flash
[5] Download CRAMFS image to Nand Flash
[6] Download YAFFS image (root.bin) to Nand Flash
[7] Download Program (uCOS-II or TQ2440_Test) to SDRAM and Run it
[8] Boot the system
[9] Format the Nand Flash
[0] Set the boot parameters
[a] Download User Program (eg: uCOS-II or TQ2440_Test)
[b] Download LOGO Picture (.bin) to Nand  Flash
[l] Set LCD Parameters
[n] Enter TFTP download mode menu
[o] Download u-boot to Nor Flash
[r] Reboot u-boot
[t] Test Linux Image (zImage)
[q] quit from menu
Enter your selection: 8
然后选择8 重启系统开发板才会运行系统。
我想问下，为什么会这样？怎样才能使开发板一上电就自动运行呢？