[U-Boot] Nand dump and nand bad block disagree

Scott Wood scottwood at freescale.com
Thu Mar 1 00:14:56 CET 2012

On 02/29/2012 04:54 PM, Mike Frysinger wrote:
> On Wednesday 29 February 2012 17:37:32 Scott Wood wrote:
>> Do you migrate the bad block markers to the new location prior to using
>> a chip?
> we leave that as an "exercise for the user" ;)
> this OOB layout is only used when the processor is booting directly from NAND, 
> so the layout already has to be adjusted in order for it to boot at all.  if 
> you aren't booting from NAND, we recommend to customers to stick with the 
> standard OOB layout.  so there isn't really a point in time where we could add 
> code to automatically migrate layouts.

OK.  I guess it depends how you prepare the bootable image -- if you
prepare a NAND boot by first booting U-Boot from something else, it
would still be a U-Boot issue.  If you write the image from something
that isn't U-Boot, obviously the migration has to happen in that other

We'll be getting into a similar situation on FSL eLBC with the hack to
support 4K NAND.  I plan to have U-Boot do the migration if it doesn't
see a special marker that asserts the migration has already happened.
This will be needed even when not booting from NAND.  Booting from NAND
with this hack would be an additional headache, and probably just not
safely possible with a lot of 4K NAND chips that want 4-bit ECC which
eLBC doesn't support.


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