Some questions on bit-flips and JFFS2

[Ricard Wanderlof]

On Wed, 5 May 2010, Norbert van Bolhuis wrote:

>> I've already thought about something like this:
>> 1. After first succesful bootup dump a mtd0 image and calculate a md5sum of
>> it:
>> nanddump -o -b -f mtd0.img /dev/mtd0
>> 2. Before each shutdown dump the image again and check if the md5sum has
>> changed.
>> 3. If it has changed write the initial dump back:
>> flash_eraseall /dev/mtd0
>> nandwrite -p /dev/mtd0 mtd0.img
>>
>> Would this be the right method?
>
> yes that's the idea, given that "refreshing" really helps to prevent
> (actually delay) future read disturbs.
> ...
>
> Another problem is a sudden reboot (e.g. crash or power-loss). There's 
> no check then.

Also, if a power failure occurs during erase or nandwrite the system will 
not boot next time.

/Ricard
-- 
Ricard Wolf Wanderlöf                           ricardw(at)axis.com
Axis Communications AB, Lund, Sweden            www.axis.com
Phone +46 46 272 2016                           Fax +46 46 13 61 30