[Arm-netbook] Disecting mmcblk0p1 and the boot process

[Frans Pop]

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.
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. It means that I should be able to:
- boot D-I from external SD card using the flash boot procedure
- have the included initrd mount that external SD card and use that as the
  source for additional components (udebs)

It also means the internal flash remains free during the installation and 
can thus be partitioned and used as we like (excluding the first
"partition" which remains reserved for u-boot and kernel).

Cheers,
FJP