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Date: Thu, 16 Jul 2009 22:54:38 +0200
From: Gilles Casse <list@gcasse.net>
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Subject: Re: UBIFS Corrupt during power failure
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Cc: Eric Holmberg <Eric_Holmberg@Trimble.com>,
	Jamie Lokier <jamie@shareable.org>,
	linux-mtd@lists.infradead.org, Urs Muff <urs_muff@Trimble.com>,
	Stefan Roese <sr@denx.de>, Nicolas Pitre <nico@cam.org>,
	Adrian Hunter <adrian.hunter@nokia.com>
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Artem Bityutskiy a écrit :
> On Wed, 2009-07-15 at 15:36 -0600, Eric Holmberg wrote:
>   
>> indeterminate state for the entire PEB.  Writing all zero's to the
>> header as in Artem's fix should work in all cases excluding the
>> extremely rare cases where a write of 0's is interrupted and the header
>> has been changed to a valid value and in the case where an erase
>> (0-to-1) transition is interrupted which results in a valid header.  The
>> odds against that are huge, so I would expect the flash to wear out
>> before it ever happens in real life.
>>     
>
> Hmm, we can zero out both headers completely by writing 128 bytes,
> even.
>
>   
According to a fellow electronician, Marc, offlist, it would not be safe
to force at 0 a bit already at 0 in flash.
For zeroing a byte, he recommends to write its complementary value (e.g.
if 0x85 is read then write 0x7A).

Best regards,
Gilles