[U-Boot-Users] Using tools/mkimage

Marc Singer elf at buici.com
Tue Aug 5 09:35:13 CEST 2003

On Tue, Aug 05, 2003 at 09:08:22AM +0200, Wolfgang Denk wrote:
> In message <20030805020001.GA15284 at buici.com> you wrote:
> > I'm having trouble understanding how an image should be created.  
> See the README. See the U-Boot and Linux Guide
> at http://www.denx.de/twiki/bin/view/DULG/WebHome

Nice to see some organized documentation.  I'm not finding mkimage in
the table of contents.  Where is it described?

> > It was my intention to use the zImage file already compressed with a
> > loader.  RAM starts at 0xc0000000, the kernel wants to load, after
> It makes no sense to use a zImage file. It was one of the  intentions
> of  U-Bot  (well,  it  was PPCBoot then) to get rid of this bootstrap
> loader.

Perhaps it is strong to say "no sense".  In fact, there is a good
reason to use zImage when u-boot is one of several methods of booting
a kernel.  It helps us to know that the same exact code is running in
every situation.

> > decompression, to 0xc00c8000.  Normally, compressed kernel images are
> > loaded at 0xc0008000.
> > 
> >   tools/mkimage -A arm -C none -a 0xc0008000 -d zImage image
> I don't see any use of the "-e" option in this command. And zImage is
> not what you want. If you want to use an  uncompressed  kernel  image
> this should be something like
> 	mkimage -A arm -O linux -T kernel -C none -a 0x0C008000 \
> 	-e 0x0C008000 -n 'ARM Linux' \
> 	-d arch/arm/boot/compressed/piggy uImage

I'm not sure what you mean.  Setting -a sets -e automatically.

Where do you get a uImage file?

I'm not sure why, but it appears to be working now.  It is probable
that one of the components was out-of-sync.

I'm on to a new problem.  For some reason, a kernel booted from blob
returns a bogo-mips value of 79 while the same kernel booted from
u-boot returns a bogo-mips value of 39.  It's an intriguing mystery.


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