-----Original Message----- From: Simon Kagstrom [mailto:simon.kagstrom@netinsight.net] Sent: Friday, September 04, 2009 12:00 PM To: Prafulla Wadaskar Cc: u-boot@lists.denx.de; Ashish Karkare; Prabhanjan Sarnaik Subject: Re: [U-Boot] [PATCH v3 4/4] tools: mkimage: Add: Kirkwood Boot Image support (kwbimage)
Hi Prafulla!
I see the complications and understand that it might be difficult to get it running.
Dear Simon So we can keep this complex enhancement for future updates, keeping this patch simpler
On Thu, 3 Sep 2009 07:15:48 -0700 Prafulla Wadaskar prafulla@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.
Again it would be problem it image size jumps over sector size boundary
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 :-)
You will have to waste 128Kbytes-512bytes on sheevaplug :-) Finally you will waste one extra sector (u-boot.kwb size is ~160kb)
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.
Currently it is done in the way I explained with some reference, I will do some exercise with your suggestions and let you know.
Regards.. Prafulla . .
Thanks for the explanation!
// Simon