[U-Boot] [PATCH v3 4/4] tools: mkimage: Add: Kirkwood Boot Image support (kwbimage)

[Simon Kagstrom]

Hi Prafulla!

I see the complications and understand that it might be difficult to
get it running.

On Thu, 3 Sep 2009 07:15:48 -0700
Prafulla Wadaskar <prafulla at marvell.com> wrote:

> > I think it could also be useful to be able to produce just the boot
> > header without the U-boot image. For example if you want to place
> > U-boot at some other location on the flash or (as a developer)
> > frequently re-flash U-boot, but don't want to write to the first block
> > all the time (you only need to rewrite it when moving U-boot).
>
> This is not possible.
> Boot Header is a part of Kirkwood boot image,
> Header contains u-boot imagesize so for this, first block need to be written each time.

Understandable. On the other hand, it should be possible to pad the
U-boot image to some specific size to keep the size constant. Typically
to the erase size.

> Secondly u-boot header is of 512bytes only whereas minimum sector size could be 4kbytes (typical),
> so rest part of first sector will be a waste.

I'd be prepared to waste a couple of bytes :-)

> Also at the end of boot image checksum need to be calculated on entire image including header.

This is not how I read the documentation. I thought the 32-bit checksum
is for the image only, not the headers? Anyway, if it does include the
headers, then I see why this would be impossible.


Thanks for the explanation!

// Simon