笔者一不小心把板子的环境变量清空了，按照之前的方法配置，NFS挂载一直失败报错：
把网上的几种经典报错找遍了也没找到问题。
VFS: Unable to mount root fs via NFS, trying floppy. VFS: Cannot open root device "nfs" or unknown-block(2,0): error -6 Please append a correct "root=" boot option; here are the available partitions: 0100 65536 ram0 (driver?) 0101 65536 ram1 (driver?) 0102 65536 ram2 (driver?) 0103 65536 ram3 (driver?) 0104 65536 ram4 (driver?) 0105 65536 ram5 (driver?) 0106 65536 ram6 (driver?) 0107 65536 ram7 (driver?) 0108 65536 ram8 (driver?) 0109 65536 ram9 (driver?) 010a 65536 ram10 (driver?) 010b 65536 ram11 (driver?) 010c 65536 ram12 (driver?) 010d 65536 ram13 (driver?) 010e 65536 ram14 (driver?) 010f 65536 ram15 (driver?) b300 31166976 mmcblk0 driver: mmcblk b301 31162880 mmcblk0p1 05406bd3-01 b310 7634944 mmcblk1 driver: mmcblk b311 131072 mmcblk1p1 9bbe6eee-01 b312 7493632 mmcblk1p2 9bbe6eee-02 b340 4096 mmcblk1rpmb (driver?) b330 4096 mmcblk1boot1 (driver?) b320 4096 mmcblk1boot0 (driver?) Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0) ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0) random: nonblocking pool is initialized经过检查发现nfsroot环境变量没设！！！
之前只设置了bootargs=console=ttymxc0,115200 root=/dev/nfs nfsroot=192.168.2.130:/home/lyr/linux/nfs,proto=tcp,vers=3 rw ip=192.168.2.110::192.168.2.1:255.255.255.0
把nfsroot漏了
设置一下
setenv nfsroot /home/lyr/linux/nfs saveenv欧克解决
