[Openpxa-users] PXA310: double bit errors on NAND

[Bjørn Forsman]

2011/1/16 Ricard Wanderlof <ricard.wanderlof at axis.com>:
>
> On Sat, 15 Jan 2011, Bjørn Forsman wrote:
>
>> I'd like to know how UBI images is supposed to be flashed.
>> By searching the internet I've seen people saying that it is
>> impossible to write UBI images with nandwrite and others say
>> it *is* possible. By looking at
>> http://www.linux-mtd.infradead.org/doc/ubi.html#L_flasher_algo
>> it may appear that flashing UBI images requires an UBI aware flasher?
>> But isn't the whole point of having ubinize so that you can take UBIFS
>> images and wrap them into something that non UBIFS aware flashers can
>> handle?
>
> I think there are two separate issues here:
>
> 1. When reflashing a flash with a new image you'll want to preserve the UBI
> erase counters, hence a UBI-aware flasher (e.g. ubiformat) is required. You
> can use nandwrite, but then the erase counter information is lost.

Yes, this is for production so I don't care that much about erase counters.

> 2. When flashing a virgin flash there are no erase counters to be preserved,
> so nandwrite will suffice. However, there appears to be an old 'bug' in
> nandwrite whereby all-ff pages in the source image are nevertheless written
> to the flash. All-ff pages are assumed erased by UBI, and so are never
> re-erased before subsequent usage. The problem is that some flash chips do
> not take lightly to being rewritten multiple times without an intermediate
> erase. So it's really an old bug in nandwrite, but it might not have
> manifested itself until heavy testing with UBI had been performed. There's
> more information on this in the FAQ I believe.

Interesting. Thanks!

It would be nice if someone could take a look at this 'bug' in nandwrite :-)

Best regards,
Bjørn Forsman