[U-Boot] Q: Bad bits in Nand Write

[Scott Wood]

On 02/14/2012 09:05 AM, Ran Shalit wrote:
> Hello,
> 
> I am using Micron Nand MT29F1G08ABC , with OMAP-L138 board, and I
> write the Nand with the following sequence in U-Boot:
> 1. erase block
> 2, read complete page change the first byte and then write back the
> complete page (2048 bytes)
> 3, read complete page change the next byte and then write back the
> complete page (2048 bytes)
> 4. back to 3. until page is written completely
> 
> What I see is that after about ~1200 bytes, bytes which are after the
> last offset such as 1400 and 1500 offset are not 0xff but instead one
> of the bits is zero (such as 0xbf)
> What Do you think might be the problem here ...

Read the manual for your NAND chip -- this is almost certainly violating
the chip's specs.  There's a limit on the number of partial programmings
that you can do to a page in between erases.  1, 4, and 8 are common
limits.  2048 is not.

-Scott