[U-Boot-Users] dd to generate image.

[U-Boot-Users] dd to generate image.

[Tim Chen]

Hi,
I'm using dd to generate the u-boot+kernel+rootfs image.
I executed command like..
dd if=rootfs.jffs2 of=kernel.img bs=1 seek=ROOTFS_OFFSET
But dd is quite slow, generating a 64MB image spends about 5 minutes.
I have changed bs=1 to bs=1024 or bigger, but the outputted image size
is wrong, too big.
dd manpage says that bs is the size of read/write one time.
Doesn't it make dd faster?

How do make dd faster?

-- 
--
Regards,
Tim.

[U-Boot-Users] dd to generate image.

[Richard Genoud]

2008/3/14, Tim Chen <tim.chen.86@gmail.com>:
> Hi,
>  I'm using dd to generate the u-boot+kernel+rootfs image.
>  I executed command like..
>  dd if=rootfs.jffs2 of=kernel.img bs=1 seek=ROOTFS_OFFSET
>  But dd is quite slow, generating a 64MB image spends about 5 minutes.
>  I have changed bs=1 to bs=1024 or bigger, but the outputted image size
>  is wrong, too big.

try dd if=rootfs.jffs2 of=kernel.img bs=ROOTFS_OFFSET seek=1

(bs is the block size and seek is counted in block size)

--
Richard Genoud - Adeneo

[U-Boot-Users] dd to generate image.

[Wolfgang Denk]

In message <9c1eb1b90803140101t79d577ddsa396573307b1ce21@mail.gmail.com> you wrote:
>
> I'm using dd to generate the u-boot+kernel+rootfs image.
> I executed command like..
> dd if=rootfs.jffs2 of=kernel.img bs=1 seek=ROOTFS_OFFSET
> But dd is quite slow, generating a 64MB image spends about 5 minutes.

Hm... you must be on a very slow machine, then.

> I have changed bs=1 to bs=1024 or bigger, but the outputted image size
> is wrong, too big.

Perhaps you forgot that "seek" is counting in units of "bs"; i.e.  if
you  change  from  "bs=1"  to  "bs=1024" you also have to change from
"seek=ROOTFS_OFFSET" to "seek=$(expr ROOTFS_OFFSET / 1024)"

> dd manpage says that bs is the size of read/write one time.
> Doesn't it make dd faster?

Yes, it does.

> How do make dd faster?

See above.

Best regards,

Wolfgang Denk

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[U-Boot-Users] dd to generate image.

[Tim Chen]

Thanks, my problem fixed.

On Fri, Mar 14, 2008 at 11:24 PM, Wolfgang Denk <wd@denx.de> wrote:
> In message <9c1eb1b90803140101t79d577ddsa396573307b1ce21@mail.gmail.com> you wrote:
>  >
>  > I'm using dd to generate the u-boot+kernel+rootfs image.


-- 
--
Regards,
Tim.