Hi,
after several trials, my SheevaPlug boot on NFS. I just change the bootcmd parameter, to not get uImage from tftpboot !
so, I set it:
set bootcmd 'nand read.e 0x800000 0x100000 0x400000;setenv bootargs $(console) $(bootargs_root) nfsroot=$(serverip):$(rootpath) ip=$(ipaddr):$(serverip)$(bootargs_end); bootm 0x800000'
Then, I can update my Linux rootfs... But I don't understand why it doesn't work by using kernel in tftp

After this update, I update the bootcmd and bootargs described in the chapter 2 of the documentation:
PlugComputer Development Kit Writing Jaunty Filesystem on the NAND Flash.pdf
It says:
8. At the U-Boot prompt, change the following parameters.
a. Marvell>> setenv bootargs 'console=ttyS0,115200
mtdparts=nand_flash:0x400000@0x100000(uImage)ro,0x1fC00000@0x500000(
rootfs)rw root=/dev/mtdblock2'
b. Marvell>> saveenv
c. Marvell>> setenv bootcmd 'nand read.e 0x800000 0x100000 0x400000; bootm
0x800000'
d. Marvell>> saveenv
With these commands, I have the errors:
No filesystem could mount root, tried: ext3 ext2 ext4 cramfs vfat msdos jfs
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,2)
[<c0030a14>] (unwind_backtrace+0x0/0xe0) from [<c003dbec>] (panic+0x50/0x120)
[<c003dbec>] (panic+0x50/0x120) from [<c0008ec0>] (mount_block_root+0x1d4/0x214)
[<c0008ec0>] (mount_block_root+0x1d4/0x214) from [<c0009168>] (prepare_namespace+0x16c/0x1c4)
[<c0009168>] (prepare_namespace+0x16c/0x1c4) from [<c0008734>] (kernel_init+0xc0/0xec)
[<c0008734>] (kernel_init+0xc0/0xec) from [<c0040bf8>] (do_exit+0x0/0x6ac)
So, I just update the bootargs to specify the rootfs type:
set bootargs '
rootfstype=jffs2 console=ttyS0,115200 mtdparts=nand_flash:0x400000@0x100000(uImage),0x1fc00000@0x500000(rootfs)rw root=/dev/mtdblock2'
and all is fine
