[U-Boot-Users] Re: "How to change the Magic number"

Wolfgang Denk wd at denx.de
Mon May 22 15:00:30 CEST 2006

In message <45530. at> you wrote:
>  I have a specific requirement to change the Magic number of the linux
> kernel in my embedded system.

You are off track.

>  I cound see the Magic number is defined in U-boot files:
>  1.include/image.h:#define IH_MAGIC        0x27051956
>  2.cpu/ppc4xx/start.S:     .long   0x27051956

This magic number is only used by U-Boot, and  ther  e  only  in  the
image header. It has no relevance in any way to the LInu xkernel.

>   So i can modify in u-boot to make it compatible to my Kernel (i am using
> montavista linux version 2.4.20), but i am not able to see this kindof
> info anywhere in the kernel source files.

You are looking at the wrong place. This magic number is not used  or
accessed anywhere in the Linu xkernel.

> If anyone knows how the linux magic number is generated and what are the
> files
>  need modifications inorder to change magic number please let me know.

Linux itself has no such magic number. Especially not on PPC.

[But if you find a way to change  that  magic  number,  I  would  not
protest  if  you  added 10 or 20 to the last 4 digits. Just make sure
the change is propagated back to it's origin. :-) ]

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
The easiest way to figure the cost of living is to take  your  income
and add ten percent.

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