nfs启动，到解压内核后就停了，求助

uboot中参数如下
bootargs root=nfs nfsroot=192.168.7.78:/root/3250/rootfs_320x240 ip=192.168.7.236 console=ttySAC0,115200 init=/init
或者这样
setenv bootargs root=/dev/nfs rw nfsroot=192.168.7.78:/root/3250/rootfs_320x240 ip=192.168.7.236:192.168.7.78:192.168.7.1:255.255.255.0:3250fs:eth0:off  console=ttyS0,115200 mem=64M

启动log如下
U-Boot 1.3.3 (May 5 2009 - 13:04:13)

DRAM: 64 MB
NAND: 256 MiB
In: serial
Out: serial
Err: serial
Hit any key to stop autoboot: 0

NAND read: device 0 offset 0x200000, size 0x1a44c4

Reading data from 0x3a4000 -- 100% complete.
1721540 bytes read: OK
## Booting kernel from Legacy Image at 81000000 ...
Image Name: Linux-2.6.27.8
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 1721476 Bytes = 1.6 MB
Load Address: 80008000
Entry Point: 80008000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK

Starting kernel ...

Uncompressing Linux.............................................................
......................... done, booting the kernel.
====================================================================我是分割线
如果从flash启动是能够用nfs挂载的