[U-Boot] u-boot fails to uncompress a "gzip'ed -9" kernel

[Wolfgang Denk]

Dear "N. van Bolhuis",

In message <49746A3B.5070706 at aimvalley.nl> you wrote:
> 
> A certain powerpc 2.6.28 kernel (which is by default compressed with
> gzip -9) fails to load with u-boot v2008.10. It results in a machine
> check stop. I'm testing on a MPC8313-RDB.
...
> If I manually compress that same kernel with "gzip -8" and generate a
> uImage, it *does* work.

Are you sure it is only an issue of gzip compression, and not for
example of image sizes?

> As far as I know my start/load memory addresses are ok.

Are you sure?

> => run tird

<sarcasm>
Excellent information. Now we all know *exactly* which commands you
might be running :-(
</sarcasm>

> Filename 'uImage'.
> Load address: 0x2000000
> Loading: #################################################################
>           #####################################################
> done
> Bytes transferred = 1717604 (1a3564 hex)
...
> ## Booting kernel from Legacy Image at 02000000 ...
>     Image Name:   Linux-2.6.28wa2
>     Created:      2009-01-19  11:36:09 UTC
>     Image Type:   PowerPC Linux Kernel Image (gzip compressed)
>     Data Size:    1717540 Bytes =  1.6 MB

So your compressed image is 1717540 bytes or 1.64 MB...

> ## Flattened Device Tree blob at 00400000
>     Booting using the fdt blob at 0x400000
>     of_flat_tree at 0x00400000 size 0x00002b7a
>     Uncompressing Kernel Image ...

And your device tree is at 4 MB. If compresses better than some 40%
than the uncompressed size of the kernel will exceed the 4 MB limit,
thus overwriting your device tree blob.

Are you *really* sure that your addresses are OK? What happens when
you move the DTB to a much higher address?

Best regards,

Wolfgang Denk

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