about syncflash lock and jffs2

[w h]

Hi,everyone:

I've worked on Moto Dragonball MX9328MXL for more than 4 months and on 
jffs2 for about two months. But Now some problems in mtd and jffs2 trouble 
me so much that I almost tear my hair and can do nothing. I do need some 
help.

I try to use jffs2 as root filesystem on SyncFlash(micron mt28s4m16lc_6, 
two chips, total 16M) in my board. Linux OS and jffs2 root fs can start up 
but with some infomation like this:
...
Erase at ****(some address) failed immediately:-EROFS.Is the sector locked?
Erase at ****(some address) failed immediately:-EROFS.Is the sector locked?
Erase at ****(some address) failed immediately:-EROFS.Is the sector locked?
Erase at ****(some address) failed immediately:-EROFS.Is the sector locked?
Erase at ****(some address) failed immediately:-EROFS.Is the sector locked?
Erase at ****(some address) failed immediately:-EROFS.Is the sector locked?
...

after it starts up, I run 
#cat /proc/mtd
dev:         size       erasesize    name
mtd0:     00100000       20000    bootloader
mtd0:     00200000       20000    kernel
mtd2:     00B00000       20000    filesystem
mtd3:     00200000       20000    fdisk

but if I try to "mkdir" or save file in some directory,it gives "Permission 
denied"

if running "cat /proc/mounts", I can see: 
/dev/mtdblock/2 / jffs2 rw 0 0 
……………………………… 
……………………………… 
#df 
filesystem           1k -block    used    available use% mounted on 
/dev/mtdblock/2    13312       13312        0       100%     / 
……………………………………………………………………………… 
……………………………………………………………………………… 
the size of filesystem partition is 11M , the jffs2.img which I download 
only takes up 6M, how dose "use%=100%" come from? 

What I use is SyncFlash(micron mt28s4m16lc_6, two chips, total 16M), is it 
posssible that the SyncFlash is locked(refer to the startup information) so 
I can't "mkdir" or save file?
Does anyone know the specific parameters when using command "unlock"?

Thanks.

Best Reguard to everyone who see this mail,
susan

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