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Possible bug in Flash-Abstraction-Layer or filesystem of Windows CE 4.2? RRS feed

  • Question

  • Hi,

    i discovered a problem with Windows CE 4.2, which appears rarely: On some devices that have been sent to us by our customers, I found damaged files. While analyzing this, I found out that these files contain a sector (512byte data) , which belongs to another damaged file. Obviously, some sectors of the nandflash-storage became mixed up.

    Many devices have got a similar kind of defect: The checksums of (nearly) all sectors in a single block of the nandflash-storage show a multi-bit-error, that means multiple bits have been toggled. I dumped these blocks to a file and opened them in a hex-editor. So I noticed that there are much more zeros in the damaged sectors than in the good ones. When writing to a sector in nandflash, a bit can only be changed from 1 to 0. Setting a bit back to 1 is only possible when erasing the whole block. Because of the very much zeros, I think that these damaged sectors have been written several times without erasing the block before. Possibly there have been sectors mixed up and assigned faultily, like in the bug described at the beginning.

    Because there are all cecksum-errors concentrated in one single block and they are always in sequent sectors, I don't think that this is a hardware defect (bad block).

    Does anyone have the same problem or does anyone know more information about this bug?

    Thanks

    Wednesday, September 25, 2013 2:46 PM