JFFS/MTD and Raw access

JFFS/MTD and Raw access

[Damien GERANTON]

Hello,

I face a strange problem, i use MTD with JFFS and i want to clone my systeme
from one card
to another.
I thought that some think like :
dd if=/dev/mtd0 of=/master.img

and

dd if=/master.img of=/dev/mtd0

But it does not work, if after i do

dd if=/dev/mtd0 of=/test.img
diff test.img master.img
i says they are different.

Is it normal.

Is RAW acces really RAW ?

Do i miss some think ?

Thanks

PS : I use MTD on 2.2.17 kernel

Re: JFFS/MTD and Raw access

[simon]

I have hit exactly the same problem using JFFS2. I am no authority 
on this but, I thought the problem might be caused by the write 
generating different OOB data for input blocks, which are erased or 
only partially written. So I guess what needs to be done is to read 
and copy the DATA and OOB. I think you can do this with the 
nanddump and nandwrite utilities. I guess I will have to try it 
sometime. 

Cheers

Simon.
On 28 Nov 2002, at 17:21, Damien GERANTON wrote:

> Hello,
> 
> I face a strange problem, i use MTD with JFFS and i want to clone my
> systeme from one card to another. I thought that some think like : dd
> if=/dev/mtd0 of=/master.img
> 
> and
> 
> dd if=/master.img of=/dev/mtd0
> 
> But it does not work, if after i do
> 
> dd if=/dev/mtd0 of=/test.img
> diff test.img master.img
> i says they are different.
> 
> Is it normal.
> 
> Is RAW acces really RAW ?
> 
> Do i miss some think ?
> 
> Thanks
> 
> PS : I use MTD on 2.2.17 kernel
> 
> 
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/


__________________________

Simon Haynes - Baydel 
Phone : 44 (0) 1372 378811
Email : simon@baydel.com
__________________________

Re: JFFS/MTD and Raw access

[Thomas Gleixner]

On Friday 29 November 2002 12:28, simon@baydel.com wrote:
> I have hit exactly the same problem using JFFS2. I am no authority
> on this but, I thought the problem might be caused by the write
> generating different OOB data for input blocks, which are erased or
> only partially written. So I guess what needs to be done is to read
> and copy the DATA and OOB. I think you can do this with the
> nanddump and nandwrite utilities. I guess I will have to try it
> sometime.
On NOR-FLASH dd should work. 

For NAND see http://www.linux-mtd/tech/nand.html

-- 
Thomas
____________________________________________________
linutronix - competence in embedded & realtime linux
http://www.linutronix.de
mail: tglx@linutronix.de

Re: JFFS/MTD and Raw access

[Kenneth Johansson]

If you have not started jffs2 on the image then they should be the same.
What is the real difference of the files? Convert to ascii first

od -Ax -tx1z /dev/mtd0 >master.txt



On Thu, 2002-11-28 at 17:21, Damien GERANTON wrote:
> Hello,
> 
> I face a strange problem, i use MTD with JFFS and i want to clone my systeme
> from one card
> to another.
> I thought that some think like :
> dd if=/dev/mtd0 of=/master.img
> 
> and
> 
> dd if=/master.img of=/dev/mtd0
> 
> But it does not work, if after i do
> 
> dd if=/dev/mtd0 of=/test.img
> diff test.img master.img
> i says they are different.
> 
> Is it normal.
> 
> Is RAW acces really RAW ?
> 
> Do i miss some think ?
> 
> Thanks
> 
> PS : I use MTD on 2.2.17 kernel
> 
> 
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

RE: JFFS/MTD and Raw access

[John Hall]

On 29 November 2002 12:35 Thomas Gleixner <tglx@linutronix.de> wrote:

> For NAND see http://www.linux-mtd/tech/nand.html

You mean http://www.linux-mtd.infradead.org/tech/nand.html

I found a small bug on the page that caused all the text from "HOWTO
implement NAND support" onwards to be in h2. Patch is here:

diff -u nand.html.orig nand.html
--- nand.html.orig      Fri Nov 29 13:02:46 2002
+++ nand.html   Fri Nov 29 13:03:49 2002
@@ -191,7 +191,7 @@
 </p>

 <hr>
-<h2>JFFS2 specific information <h2>
+<h2>JFFS2 specific information</h2>
 <h3>JFFS2 Out of Band usage</h3>

 <h4>Nand chips with 256 byte pagesize and 8 byte OOB size</h4>

Regards,
John Hall

Re: JFFS/MTD and Raw access

[Thomas Gleixner]

On Friday 29 November 2002 14:04, John Hall wrote:
> On 29 November 2002 12:35 Thomas Gleixner <tglx@linutronix.de> wrote:
> > For NAND see http://www.linux-mtd/tech/nand.html
>
> You mean http://www.linux-mtd.infradead.org/tech/nand.html
Yep
> I found a small bug on the page that caused all the text from "HOWTO
> implement NAND support" onwards to be in h2. Patch is here:
>
> diff -u nand.html.orig nand.html
> --- nand.html.orig      Fri Nov 29 13:02:46 2002
> +++ nand.html   Fri Nov 29 13:03:49 2002
> @@ -191,7 +191,7 @@
>  </p>
>
>  <hr>
> -<h2>JFFS2 specific information <h2>
> +<h2>JFFS2 specific information</h2>
>  <h3>JFFS2 Out of Band usage</h3>
>
>  <h4>Nand chips with 256 byte pagesize and 8 byte OOB size</h4>
>
Thanks
-- 
Thomas
____________________________________________________
linutronix - competence in embedded & realtime linux
http://www.linutronix.de
mail: tglx@linutronix.de