[Arm-netbook] Debian Installer fully functional for ChiTech PC89E

[Frans Pop]

The moment you've all been waiting for: installing Debian Squeeze using 
Debian Installer is, with a few limitations, as easy as installing Debian 
on any other system.

Before attempting this yourself, please read the information below 
carefully. The installation procedure has been successfully tested, but 
keep in mind that this is not rock solid code yet.

Known issues and limitations
============================

The only real issues are because our kernel is not yet perfect.

kernel issues
-------------
The installer uses and will install the 2.6.24.7 kernel Luke and I have 
been working on. This kernel is still very much work in progress. Help 
fixing the issues below would be very much appreciated!

Current known kernel issues are (roughly in order of importance):
- Internal flash (mmcblk0) gets disabled (or reset) when external SD
  card is inserted/removed.
  Do *NOT* change the SD card while the installer or Debian is running.
- System does not power off after shoutdown; use the "reset" button on
  the bottom to power off the system after shutdown.
- No driver for wireless networking available.
- The dm9000 eth0 network device has some issues and is slow to come up.
  Once up it has been reliable for me.
- Various other (less important) devices are not yet enabled or tested.

installer limitations
---------------------
- Do *not* change mmcblk0p1; this is where u-boot and the kernel live...
- The root file system *must* be formatted for ext2.
  Reason is that we don't have a initrd, so the driver for the root file
  system must be compiled into the kernel. Only ext2 and ext4dev are
  compiled in at the moment.
- ext4 is *not* usable
  Cause is probably an incompatibility between the version of ext4
  available in 2.6.24 and Squeeze userland libraries and utilities.
  A newly created ext4 partition fails to mount.
  However, the existing MidFun ext4 partitions mount correctly.
- The installer will install a "full" Debian base system, not a reduced
  emdebbian "grip" system. Maybe installing emdebbian Squeeze grip is
  possible, but that's untested. "Upgrading" to grip should be possible.
- Repository Release files are *not* authenticated. Reason is that the
  installation uses a repository on alioth for custom packages which
  does not (yet) have a signed Release file.

Debian Installer functionality
==============================

The installation is similar to "netboot" installs: only the initial 
installer image is read from SD card; all additional installer components 
and all packages are downloaded from the Internet.
I have opted for this in order to keep the external SD card completely free 
for use for partitioning and the installed system.

All installer components that are specific to the CT-PC89E are included in 
the initial installer image.

The installer has a number of customizations for the CT-PC89E:
- a micro ramdisk piggybacked onto the installation kernel that loads
  the real installer image from SD card
- the installer itself is *not* flashed, but runs entirely in RAM
- extended timeout for DHCP because of the eth0 kernel issues
- automatically adds package repository on alioth for:
  - custom kernel package
  - custom udev package: this package is identical to the Lenny version
    of udev, but with a version number bumped so it's higher than the
    current version of udev in Squeeze (I've used: 160-really0.125-1)
- installs hook scripts to run depmod and to flash the kernel to nand
- guided partitioning is skipped by default as using it is completely
  unsuitable for use on mmcblk0p1

The custom package repository can be found at:
http://arm-netbook.alioth.debian.org/dists/

The custom udev package is needed because the current version in Squeeze 
requires a 2.6.26 or later kernel.

NOTE: the kernel will automatically be flashed to Nand (mmcblk0p1) during 
the installation, and also later when upgraded using a suitable kernel 
package.

Installation tips
=================

* Do not create a swap partition; by all accounts using swap with flash
  is not a good idea.
* It is possible, using partman, to delete mmcblk0p2 and mmcblk0p3 and
  create a new mmcblk0p2 partition of ~1.9GB. Or choose your own scheme,
  but *do not* touch mmcblk0p1.

Installation HOWTO
==================

Yes, I've put this at the bottom on purpose :-)

* Create a VFAT partition on an SD card; the maximum *total* capacity of
  the SD card is 4GB; larger cards are not recognized by u-boot.
  Suggested size for the VFAT partition is 100MB; the partition *must*
  be partition 1.
* Copy the Debian Installer files from [1] to the SD card.
  The files are:
  - zImage_dt_update: kernel image + micro initial ram disk
  - datang-epc.tar.gz: dummy tarball required by u-boot
  - root.img: the actual Debian Installer image
* Boot the netbook for a "firmware update" by holding the two touchpad
  buttons and then press and hold the power button. Keep all three buttons
  pressed until you see a blue Chinese text (which presumably says the
  "firmware" image is being loaded).
* Install as usual, but please observe all the warnings listed above.

Final remarks
=============

With this milestone reached I'm going to reduce the time spent on the 
netbook a bit. However, I will update the package repository and installer 
images on alioth as improvements (in the kernel) become available.

Please share your experiences and let me (and others) know of any problems.

Enjoy,
FJP

[1] http://arm-netbook.alioth.debian.org/pub/CT-PC89E/debian-installer/
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