机器无法启动

今天我一开机就出现下面情况,昨天我准备挂载NFS的,不过没有挂成,今天出的下面的情况是不是系统没有找到根文件系统,还是分区的问题,要如何解决啊!亚瑟王帮看下,急??
VFS: Cannot open root device "nfs" or unknown-block(2,0)
Please append a correct "root=" boot option; here are the available partitions:
1f00             256 mtdblock0 (driver?)
1f01            2048 mtdblock1 (driver?)
1f02          257536 mtdblock2 (driver?)
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)
Backtrace:
[<c0039fd4>] (dump_backtrace+0x0/0x10c) from [<c02b17f8>] (dump_stack+0x18/0x1c)

r7:c380a0cb r6:c03bdf40 r5:c380a000 r4:c381df40
[<c02b17e0>] (dump_stack+0x0/0x1c) from [<c02b1848>] (panic+0x4c/0x124)
[<c02b17fc>] (panic+0x0/0x124) from [<c0008e30>] (mount_block_root+0x178/0x234)
r3:00000000 r2:c3831dac r1:c381df40 r0:c033f578
[<c0008cb8>] (mount_block_root+0x0/0x234) from [<c0008f9c>] (mount_root+0xb0/0xf
4)
[<c0008eec>] (mount_root+0x0/0xf4) from [<c00090d8>] (prepare_namespace+0xf8/0x1
8c)
r7:c03bd924 r6:c001e83c r5:c001e83c r4:c001e84c
[<c0008fe0>] (prepare_namespace+0x0/0x18c) from [<c0008478>] (kernel_init+0xc8/0
xf4)
r7:00000000 r6:c001d9d4 r5:c001d670 r4:c001d9d4
[<c00083b0>] (kernel_init+0x0/0xf4) from [<c004af30>] (do_exit+0x0/0x620)
r7:00000000 r6:00000000 r5:00000000 r4:00000000

Cannot open root device "nfs" or unknown-block(2,0)
这句话就提示你从NFS挂载失败了。
你设置了从NFS启动，然后你需要在PC的Linux中添加NFS文件系统，并且接上网线，正确配置好网络。不然你是没法从NFS启动的。
如果你要恢复为从Yaffs启动，你需要使用uboot下载模式下的命令0-》2-》5-》q，然后重新启动即可。前提：开发板中使用了命令6烧写过了yaffs文件系统。