This page will try to explain my experience with jtag cable.

Hardware

• JTAG cable

Software

Currently supported jtag utility is UrJTAG

dependencies

apt-get install libreadline-dev

checkout source

svn co https://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk urjtag
cd unrjtag

include

cd include
./autogen.sh
sudo make install
cd ..

jtag

cd jtag
./autogen.sh
make
make install

Connect to device

Load kernel module

modprobe ppdev

Start jtag tool

$ jtag
jtag> cable ppdev /dev/parport0 WIGGLER
Initializing Macraigor Wiggler JTAG Cable on ppdev port /dev/parport0
jtag> detect

This page accompanies git repository at http://git.rot13.org/?p=bcm963xx.git;a=summary

Dump existing firmware

Instructions based on http://www.piccato.it/openwgate/backup_e_restore

mount -t tmpfs -o size=4m tmpfs /webs
ln -s /dev/mtdblock0 /webs/mtblock0.gif

It doesn't work for me because my image doesn't have ln

Here are my notes how to configure pppoe-server to run as server for ADSL modem.

Prerequisits

This list might be incomplete

apt-get install pppoe

PPP configuration

/etc/ppp/pppoe-server-options

# PPPoE server
#nologin
mru 1492
noreplacedefaultroute
proxyarp
ms-dns 192.168.1.1

/etc/ppp/pap-secrets

# PPPoE server
#client	hostname	<password>	IP
test	*		"test"		*

/etc/ppp/chap-secrets

# client	server	secret	IP addresses
test		*	test	*

Configuration

We will have fake network 10.0.0.0 on IP alias eth0:1 and will give out addresses in that range. While we could go with just one network, this is more clean, since we will see difference in packets traveling over PPP link as opposed to direct connection.

ifconfig eth0 192.168.1.90 up
ifconfig eth0:1 10.0.0.1 up

PADI

pppoe-relay -B eth0:1 -C eth0 -n 1 -F

PPPoE

pppoe-server -I eth0:1 -T 60 -C fake -S fake -L 10.0.0.2 -R 10.0.0.10 -N 1 -F

NAT

iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -j SNAT --to-source 192.168.1.90

Debugging

To sniff all traffic expect web (I guess that most ADSL modems have web interface) use something like:

tshark -i eth0 -f '!port 80'