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

[Wolfgang Denk]

In message <9c1eb1b90803140101t79d577ddsa396573307b1ce21 at 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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