VP5500

The VP5500 booting

The Philips VP5500 is a WLAN VOIP- & Video Phone sold by KPN in the netherlands. Some of the features, such as configuration settings for the VOIP connection are usually hidden from the user, but can be revealed through a fake firmware image (description here). Thanks to this restriction the device was rendered useless when KPN decided to disconnect the VOIP services this phone was relieing on.

This article intends to collect all relevant information about the hard- & software on the telephone and to provide information to actually reuse the hardware.

Hardware

• CPU: MC9328MX21 @ 266MHz (ARM9 Core)
• FS455LF: PAL Video converter chip
• Wlan: Marvell 88w8385 (OSS driver, Datasheet)
• RAM: 64MB (2x K4S56163LF)
• Flash: 16MB
• Kamera: Chicony dc-4626.a5
• Audio Codec: TI TLV 320 AIC 12K

GPIO Interfaces

The script /usr/local/tmp/HD1_ats.sh is a test script for the developers. This script contains a lot of information about how to control peripheral devices of the phone (such as backlight).

• VP5500/GPIO_backlight

Pinning

Serial

serial pins beneath the battery

VCC: 3.3V, Rate 115200 Baud

Setting the "TIN" Pin to low or pressing keys while the bootloader is waiting will redirect first Console to the serial device. Fortunately the bootloader allows editing the kernel command line, so you're able to directly "chroot" the device by setting a different initrc (sh). Type the following at the bootloader prompt:

boot root=/dev/mtdblock2 init=/bin/sh

• Boot Log of the standard installation
• How to add a serial interface to your device

JTAG

Pins are at the back of the circuit board.

Partitions

0x00000000-0x00014000 : "bootloader"    blob version 2.0.5-pre2
0x00014000-0x00100000 : "kernel"        /boot (?)
0x00100000-0x01ce0000 : "fs #1"         /
0x01ce0000-0x01fe0000 : "fs #2"         /user_data
0x01fe0000-0x02000000 : "fs #3"         /user_settings

Drivers & Software

Audio

• Looks as if the audio codec in use needs a proprietary driver

MPEG en/decoder

• Hantrop MPEG EN- DECODER, kernel module: hmp4e

Camera

• Patch for 2.4.X - CMOS Sensor connected via I²C

Wlan

• Libertas OSS driver

Framebuffer

This shows an example of the visible (white are w/ logo) vs. virtual (striped) framebuffer size

Although the display is 176x220, the framebuffer has a virtual size of 240x220 pixels.

Creating an own splash image

• Create an image with 240x220 pixels in size
  • Note: The on-screen visible area of this image is in the upper left corner with a size of 176x220 (actual display size). Furthermore the image is flipped upside down.
• Save it as RGB565 Bitmap (=5b for R, 6b for G, 5b for B) (gimp can do this for you)
• Strip off the BMP header:

  tail -c 105600 your_bitmap.bmp > your_splasimage.bin

• Copy your shiny new splash image to /user_data/data/welcome.rgb565

2nd Splash image

Example bootlogo

The 2nd image is an animated GIF file and can be found in /usr/local/pics/qpe/splash.gif

Software

Bootloader (Blob)

• Project download page

Root FS & Toolchain

According to the boot log, the root fs is derived from some sample source code for the iMX21 development platform.

• process list

Kernel

Version: 2.4.20

• modules in use

Misc

To run the applications in /usr/local/bin, run export QTDIR=/usr/local first.

Boot process

Scripts & programs run at boot time:

• /etc/rc.d/rcS
• /etc/rc.d/init.d/*
• /usr/local/startup/daemon.sh (invoked by inittab)
  • qpe
  • upgraded
  • netsyncd

Networking stuff

WPA Settings can be configured by editing the file /etc/marvell/wpa_supplicant.conf (vi is installed).

Example:

network={
 ssid="your_ssid"
 scan_ssid=1
 proto=WPA
 key_mgmt=WPA-PSK
 pairwise=TKIP
 group=TKIP
 psk="your_passphrase"
}

The default configuration restricts WPA Supplicant to operate only in WPA1 mode. WPA2 can be enabled by changing the configuration like this:

network={
 ssid="your_ssid"
 scan_ssid=1
 #proto=WPA
 #key_mgmt=WPA-PSK
 #pairwise=TKIP
 group=TKIP
 psk="your_passphrase"
}

This change will also persist when selecting another access point through the menu.

Configuration

For Sipgate:

SIP1 Display Name: your Name

User Name: your SIP-ID

Telephone Number: Tel.Nr.

Auth

Authentification UserName: your SIP-ID

Password: Sipgate Password

Server

SIP register address:port: sipgate.de:5060

Proxy

SIP proxy1 address:port: sipgate.de:5060

SIP2

SIP Port Listen

for UDP: 5062

for TCP: 5062

for TCP TLS: 5053

SIP Outbound needs to be empty.

Making Backups

If you want to make a backup of your root partition, you can do as follows:

echo '#!/bin/sh' > /tmp/backup.sh
echo 'cat /dev/mtdb2' >> /tmp/backup.sh
chmod 700 /tmp/backup.sh
micro_inetd 31337 /tmp/backup.sh

This'll make your device listen for incoming connections on port 31337. On your host system you may then simply run "nc ip.of.your.phone 31337 > /path/to/backup/file" - et voilà, you got your rootfs packed into a file. Note that the backed up file is not ext2, but a jffs2 formatted filesystem. These can't be handled by a simple "mount -o loop" as you'd have thought... so here's how you mount it:

modprobe jffs2
modprobe mtdram total_size=32768 erase_size=128
modprobe mtdblock
mkdir /tmp/phone-root
mknod /tmp/phone-mtdb2 b 31 0
dd if=/your/backup/file of=/tmp/phone-mtdb2
mount -t jffs2 /tmp/phone-mtdb2 /tmp/phone-root

This was easy, wasn't it? ;)

Links

• Thread where the actual reverse engineering happens
• Results will be demonstrated on the workshop root your toaster (2010/05/01)
• Hack to reveal the Config interface
• some more information
• Binary packages for the VP6500 (most of it should be compatible)