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

[Simon Kagstrom]

On Fri, 04 Sep 2009 12:57:57 +0200
Wolfgang Denk <wd at denx.de> wrote:

> Dear Simon Kagstrom,
> 
> In message <20090904103602.7a0ec3fd at marrow.netinsight.se> you wrote:
> > 
> > > > 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.
> > > 
> > > This makes no sense. Why would such padding be needed? It only adds
> > > overhead everywhere where the image needs to be processed, stored,
> > > downloaded, programmed, etc.
> > 
> > In this case to have keep the kirkwood boot header unchanged, and to
> > just update the U-boot image.
> 
> Doesn't the header contain checksums and such? And what would that
> save you?  Building the image with header is supposed to be a very
> cheap operation.

I believe the checksums are for the header and the header extension -
the image itself contains a checksum in the last 4 bytes.

The idea was to avoid having to rewrite the same block all the time.
Anyway, Prafulla has explained why it's difficult (or maybe impossible)
to use this method, so I think we can safely drop this subject for now.

// Simon