UBI and volume checksum

UBI and volume checksum

[Giovanni Malfara']

Hi all,

I need to verify that the UBI image once it has been written on the UBI
volume.
So I try to extract the content with the "dd" tool from the UBI bolume
and I calculate the checksum to be compared with the one of the original
UBI image.

My question is: is it always true? If I extract the content of the UBI
volume at any time (the fileystem is mounted read-only) , will the
checksum always the same? Will the data move from a PEB that has
bit-flips to a new one cause a difference in checksum?

Is this the best way to achieve this?

Thansk in advance.

-- 
Giovanni Malfarà

Re: UBI and volume checksum

[Artem Bityutskiy]

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On Thu, 2012-06-07 at 14:21 +0200, Giovanni Malfara' wrote:
> Hi all,
> 
> I need to verify that the UBI image once it has been written on the UBI
> volume.
> So I try to extract the content with the "dd" tool from the UBI bolume
> and I calculate the checksum to be compared with the one of the original
> UBI image.
> 
> My question is: is it always true? If I extract the content of the UBI
> volume at any time (the fileystem is mounted read-only) , will the
> checksum always the same? Will the data move from a PEB that has
> bit-flips to a new one cause a difference in checksum?

Yes, if you read the UBI volume (/dev/ubiX_Y), and it is R/O, the CRC
should be the same all the time.

-- 
Best Regards,
Artem Bityutskiy

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Re: UBI and volume checksum

[Giovanni Malfara']

On 06/07/2012 02:51 PM, Artem Bityutskiy wrote:
> On Thu, 2012-06-07 at 14:21 +0200, Giovanni Malfara' wrote:
>> Hi all,
>>
>> I need to verify that the UBI image once it has been written on the UBI
>> volume.
>> So I try to extract the content with the "dd" tool from the UBI bolume
>> and I calculate the checksum to be compared with the one of the original
>> UBI image.
>>
>> My question is: is it always true? If I extract the content of the UBI
>> volume at any time (the fileystem is mounted read-only) , will the
>> checksum always the same? Will the data move from a PEB that has
>> bit-flips to a new one cause a difference in checksum?
> Yes, if you read the UBI volume (/dev/ubiX_Y), and it is R/O, the CRC
> should be the same all the time.
>
Thank you very much Artem!
Best Regards,

-- 
Giovanni Malfarà

Re: UBI and volume checksum

[Giovanni Malfara']

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Hash: SHA1

On 06/07/2012 02:51 PM, Artem Bityutskiy wrote:
> On Thu, 2012-06-07 at 14:21 +0200, Giovanni Malfara' wrote:
>> Hi all,
>>
>> I need to verify that the UBI image once it has been written on the UBI
>> volume.
>> So I try to extract the content with the "dd" tool from the UBI bolume
>> and I calculate the checksum to be compared with the one of the original
>> UBI image.
>>
>> My question is: is it always true? If I extract the content of the UBI
>> volume at any time (the fileystem is mounted read-only) , will the
>> checksum always the same? Will the data move from a PEB that has
>> bit-flips to a new one cause a difference in checksum?
>
> Yes, if you read the UBI volume (/dev/ubiX_Y), and it is R/O, the CRC
> should be the same all the time.
>
HI,

If I try to read back from the volume (using "dd") after I write the
NAND Flash (using "ubipudatevol") I get a different value compared to
the CRC of the image file for the CRC of the volume content if there are
some bad blocks.
Do I have to use another tool (e.g. nanddump)?

Thanks in advance,
Giovanni

- -- 
Giovanni Malfarà
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Re: UBI and volume checksum

[Artem Bityutskiy]

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On Mon, 2012-06-18 at 22:22 +0200, Giovanni Malfara' wrote:
> If I try to read back from the volume (using "dd") after I write the
> NAND Flash (using "ubipudatevol") I get a different value compared to
> the CRC of the image file for the CRC of the volume content if there are
> some bad blocks.
> Do I have to use another tool (e.g. nanddump)?

Could you please create a small test script which demonstates this and
send it?

-- 
Best Regards,
Artem Bityutskiy

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