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Bad block table

Manu
Prodigy 110 points

Hi,

I have a few doubts about bad block table (bbt),

1 > U-boot create a bbt, why cant the kernel use the same bad block table created by U-boot ?

2 > In case of U-boot the bad block table will be created on the Flash device itself,  where will the bbt of kernel be stored ? Will it by any chance over write the bbt of u-boot ?

Thanks

  • 0
    Guru 31670 points

    U-boot Bad block is stored in the last 4 pages of the last block of the device. The pages are marked as bad again. Kernel can choose to use the u-boot's table or it maintain its own table. Easiest approach followed by kernel is to mark the first two bytes of the spare area with a magic value, which if written will be treated as bad block. Even the factory bad block markings are  also like this. It will be useful to use the same methodology as kernel as it will be useful during mass production. 

    Again factory bad block markings can be different according to the vendor also.