After lots's of tries and help from different people I got my own kernel running on the N900, which is based on the Debian kernel package. So far it just offers basic features (e.g. framebuffer, keyboard) and is missing some important ones (e.g. touchscreen).
To test it on your phone you need to do have Debian installed on an µSD card, install uboot on the N900 (as described in Debian on N900: U-Boot) and install the kernel package.
You can fetch the package from http://pkg-n900.alioth.debian.org. I also uploaded the kernel config next to the package, so that you can check if a specific feature is enabled.
I will ask for inclusion into the official package now.
After some time writing the phonet dissector for wireshark in lua I noticed the disadvantages:
So I tried the C interface. I found the basic structure for plugins pretty fast in their documentation and thought about some design changes in the plugin:
A word and a blow. The new plugin is available in this isi-wireshark-plugin repository.
I took some deeper looks on these packets and found the time and date information from the GPS data packets. Then I found out, that some guy from the Maemo community reverse engineered quite some stuff about it already and added all that to the plugin. The dissection of a GPS packet now looks as follows:
So the basic features of GPS are available (position,date/time,movement). Missing though are status fields, satellite information and AGPS stuff. Screenshot
The guy from the Maemo community, Luke Dashjr, who reverse engineered the GPS data packet contacted me the other day and told me he found out about the missing bits, so I'm pleased to announce, that the wireshark plugin does know about satellite info now. The only missing bit is A-GPS!
In the last days I finally got some bits out of the Nokia N900's modem
on Debian without any properitary tools. For now it's just the following
information:
manufacturer: "Nokia"
model: "Nokia N900"
revision: "V ICPR82_10w08 25-02-10 RX-51 (c) Nokia"
But the most difficult part is probably done. My next plan was to get
the modem connect to a mobile network, which requires an unlocked SIM
card. Unfortunately ofono does not yet
support SIM cards with PINs. Thus I had to find another way to get out
how to perform this task.
I started reverse engineering the properitary sscd, but got annoyed of it
pretty fast (it's lots of work for just a little bit of information). I
thought it might be easier to analyze the network traffic, since I know
the basic format of these messages anyway. So I installed tcpdump in maemo
and added the following event.d rule as /etc/event.d/tcpdump:
description "tcpdump on phonet0"
author "Sebastian Reichel"
start on started dbus
stop on stopping dbus
service
respawn
respawn limit 10 1
console output
exec tcpdump -i phonet0 -w /root/phonet.log
This worked at one go and I had a log file with ~300 packages in it (this is the amount
of packages generated during maemo's boot phase). The packages were detected as
SLL packages by wireshark. This means there
was just one blob of data, thus I deceided to write a plugin for Phonet. After some
searching I deceided to use the lua interface,
since it looked quite easy. I got hit by one problem while coding the (still very basic)
plugin, which needs patching of wireshark (Debian Bug #594390).
Now check the IMHO amazing result:
Note, that the plugin covers only some commands and is far from being complete. It will append all data, which has not been analyzed in an extra field.
As of Revision 34101 Wireshark does support ssl.ltype dissectors, so the patch is not needed with it anymore.
You must add the parameter "-s 0" to the tcpdump call or it will limit the packet size.
First of all the Debian on N900 page moved to https://elektranox.org/n900. Now about the recent changes:
As I promised in my last post I improved Debian support. The changes since initial Debian support are:
