[Arm-netbook] Disecting mmcblk0p1 and the boot process

Luke Kenneth Casson Leighton luke.leighton at googlemail.com
Mon Mar 15 12:35:36 GMT 2010

On Sun, Mar 14, 2010 at 7:53 PM, Frans Pop <elendil at planet.nl> wrote:
> I think I may have found how they are flashing the root file system.
> This is not yet verified.
> There are two kernel images in the firmware tarball:
> - zImage_dt
> - zImage_dt_update
> The first we know is the kernel copied to flash and what is booted during a
> normal system boot.
> The second is quite a bit larger. I suspect that it's a kernel with an
> initramfs initrd piggybacked on top of it.

 yes, i concur.  it was a few days ago, after i stayed up a bit too
late and things are a bit hazy but i believe that what i did was
ignore the initramfs and zcatted the file, then, running strings on
it, found the boot params.  rootfstype=cramfs was one of them.

 there is a standard procedure described in the u-boot man pages for
doing multi-file but there is no "de-multi-filer" that i can find.

> This initrd would then contain a simple Linux system that partitions the
> flash, creates file systems on the 2nd and 3rd partition and extracts the
> root FS.
> The really nice bit is that this same procedure should also work nicely for
> Debian Installer.

 absolutely.  _if_ we can work out how to create the vmlinuz+initrd

 the alternative procedure - booting "as-is" by placing D-I in a
tarball, to be unpacked into a ramfs and then pivot_rooted - was in
lieu of not being able to do that.


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