[U-Boot-Users] Accessing mkimage checksum

Wolfgang Denk wd at denx.de
Wed Apr 26 22:14:15 CEST 2006

In message <200604261502.02751.ngustavson at emacinc.com> you wrote:
> > So what is your problem - you have the image, and want to write it to
> > flash. Why would you need any additional tools for that?
> Because I want to write it through the uClinux MTD layer, which has nothing to 
> do with u-boot, other than the fact that the flashing utility needs to 
> calculate a checksum and verify it against the package, which is  
> the "ubootian" format created by mkimage.

Maybe you explain in more detail what you intend to do. I  don't  see
why "the flashing utility needs to calculate a checksum" - the uImage
file  already  has  two  checksums,  so  no new calculation should be

If you use the MTD layer as a blockdevice, you will probably  have  a
file  system  there; then you can just use "cp" as "flashing utility"
and "mkimage -l" to verify the checksums after writing.

If you use a character device, you can just  use  "cp"  as  "flashing
utility"  and  "mkimage  -l"  to  verify the checksums after writing;
probably an additional step will be nedded  to  reead  back  the  MTD
character  device  in a file, making sure only the original amount of
data is read back; a tiny shell script based on "ls"  and  "cut"  and
"dd" will do).

I have no idea what you could need special tools for.

> This is really a question for both the uClinux and u-boot communities.

Actually this has nothing to do with uClinux, and  very  little  with

> If a section of what I'm asking does not apply to your work then please ignore 
> it. 

You post her, I reply here.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
If there was anything that depressed him more than his own  cynicism,
it was that quite often it still wasn't as cynical as real life.
                                 - Terry Pratchett, _Guards! Guards!_

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