Write NAND Error

Hello, i have mini6410... i could install WinCE6 and Android 2.3.4 through
SD Card several times. but when i decided to install another image of
Android, the NAND flash corrupted... after that i am not able to install
any image ):
for example when i push my SD Card into Mini6410 (with NK.bin,
NBOOT-RAM256.nb0,...) while S2 is in SDBOOT state,it can "Load NK.bin from
SD card..." %100, but it can not install unpacked NK.bin.
the progress fills until %6 and suddenly prompts "Write NAND Error"
how to solve my problem.
also i could not use dnw to format NAND flash... because my PC don't know
mini6410 at all(via the blue cable...)
))):

also is there any way to reset mini6410 and initialize factory settings ?

i could connect to pc via serial cable and usb, now [USB:OK]
but when i try to install an image using dnw, it says same error(Write NAND
Error)
e.g. installing from SD Card and dnw have same operations.
also i saw somethings like this:
---------------------------------
(...)
Skip block 0x3b6
Skip block 0x3b7
Skip block 0x3b8
Skip block 0x3b9
Skip block 0x3ba
Skip block 0x3bb
(...)
Skip block 0x7fb
Skip block 0x7fc
Skip block 0x7fd
Skip block 0x7fe
Skip block 0x7ff
Installing yaffs-image failed
---------------------------------
can anyone help me ?? i am very sad ))))):
(sorry for poor english.)

because your Mini6410'NandFlash has too mach bad-block so>...

(sorry for poor poor english.)

well,what is the solution? (software or hardware?)
if i change the samsung nand flash on board, will it solve ?
this is my email
hesam_um@yahoo.com
i can use translate.google.com, please type in your language
if your english is poor
where are you from?(what is your language?)

hello all,
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i am very happy...
problem solved... i bought a new Samsung Nand Flash... (it is K9F2G08U0B)
now WinCE is installed on mini6410
:))))))))))))))))
Thanks GOD
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