From mboxrd@z Thu Jan  1 00:00:00 1970
From: Frans Meulenbroeks <fransmeulenbroeks@yahoo.com>
Date: Sun, 11 Jan 2009 06:35:08 -0800 (PST)
Subject: [U-Boot] NAND bad environment block handling
In-Reply-To: <20090111132843.86CE0832E425@gemini.denx.de>
Message-ID: <817622.67175.qm@web33604.mail.mud.yahoo.com>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de


> 
> That's a pretty risky setup because  it  is  based  on 
> an  incorrect
> assumption  - on NAND, block become not only bad when being
> erased or
> written to, but also after a certain number  of  read 
> operations  is
> exceeded.  Yes, there is a maximum number of reads per
> block on NAND!
> People like to ignore that... See for example  the  Micron 
> Technical
> Note   "Design   and  Use  Considerations  for  NAND 
> Flash  Memory",
> http://download.micron.com/pdf/technotes/nand/tn2917.pdf

Thanks for the link. I was not aware of read degradation. That is what most manufacturers do not tell you.
> 
> Time to look into UBI, me thinks.

For u-boot env settings??

My problem that the designated env blocks can be bad or become bad during the lifetime of the device. Not desirable especially not for expensive devices.

Frans.