help: Erase failure:Invalid argument

[guo_zhenglin]

when I erase flash ,I get a error, message as following:

bash-2.04# eraseall /dev/mtd/4
Erasing 256 Kibyte @ 2c0000 -- 91 % complete.
eraseall: /dev/mtd/4: MTD Erase failure: Invalid argument

bash-2.04# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00800000 00040000 "MBX flash"
mtd1: 00040000 00040000 " BOOT partition(mtd/1)"
mtd2: 000c0000 00040000 "KERNEL  partition(mtd/2)"
mtd3: 00400000 00040000 "ROOT  partition(mtd/3)"
mtd4: 00300000 00040000 "APPLICATION partition(mtd/4)"


1)my environments:
  linux kernel 2.4.20, with preempt-kernel-rml-2.4.20-3.patch
  MBX860 board with AM29F016 flash
  
2)when I use linux kernel 2.4.4( download from www.denx.de),
  all is ok.
  but when I use kernel 2.4.20 (download from www.kernel.org),
  get error .
  It is linux kernel problem ,or mtd problem ,or my problem?

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 guo zhenglin 
 guo_zl9 at hotmail.com
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