Thx for your reply. I have read the Upgrade Guide,but now I can only enter the u-boot not the switch system.
Hit any key to stop autoboot: 0
u-boot>
u-boot> printenv
baudrate=9600
bootImg=Minions_UBOOT_1.1.1.bin
bootargs=console=ttyS0,9600n8 maxcpus=1 mem=496M mtdparts=brcmnand.0:256m(nrootfs),256m(ntest),-(reserve) quiet
bootcmd=run nand2boot
bootdelay=3
cpldImg=minion_syscpld_rev0307.jbc
dhcp2boot=dhcp ${fileaddr} ${diagImg}; bootm ${fileaddr};
diagImg=Minions_DIAG_1.1.4.img
et0phyaddr=1
ethact=bcm_xgs_gmac-0
ethprime=bcm_xgs_gmac-0
fdt_high=0xffffffff
fileaddr=64000000
filesize=1799904
ipaddr=172.18.60.233
loadaddr=0x64000000
mtdids=nand0=brcmnand.0
mtdparts=mtdparts=brcmnand.0:256m(nrootfs),256m(ntest),-(reserve)
nand2boot=nand read ${fileaddr} 0x0 0x5000000; bootm ${fileaddr}
serverip=172.18.60.99
stderr=serial
stdin=serial
stdout=serial
tftp2boot=tftp ${fileaddr} ${diagImg}; bootm ${fileaddr};
ubifsImg=Minions_DIAG_1.1.0_rootfs.ubifs
usb2boot=usb start; fatload usb 0:1 ${fileaddr} ${diagImg}; bootm ${fileaddr};
ver=U-Boot 2016.01-Broadcom XLDK-3.8.1-svn20090 (Oct 04 2016 - 07:22:19 +0800)
Environment size: 1029/65532 bytes
u-boot>