[U-Boot] zImage on ARM

["Loïc Minier" <lool@dooz.org>]

On Fri, Sep 03, 2010, Wolfgang Denk wrote:
> > I have a client that has asked me to look into loading zImage files
> > instead of uImage for some ARM based boards.
> 
> Why?

 It's the direct output of the kernel build process; typically,
 distributions ship a /boot/zImage-foo which gets converted into an
 uImage and flashed if the bootloader is u-boot.  If that step could be
 skipped, it would make things easier!

> > Anyone familiar with the history of why uImage is the preferred
> > format?  Just trying to learn . . .
> 
> uImage, when done correctly, avoids that you have to add a pre-loader
> (including all of gzip and what else is needed to copy the uncom-
> pressed image to it's final location in RAM) to each and every kernel
> image - which is just a waste of time and resources as we already
> have all that code present in U-Boot.
> 
> Note that the mainline ARM kernel does not make use of this; instead,
> it adds the preloader anyway.  I never understood why.

 Seems zImage is quite widespread now; would it make sense to allow
 builing u-boot without that code and rely on the kernel code to unpack?
 Or should u-boot just gain a new image type for zImage?

-- 
Lo?c Minier