Thursday, 3 July 2014

Howto install OpenWRT on Netgear DG834 or DG834G (v1 or v2)

Got a spare Netgear DG834 or DG834G? Want to try OpenWRT? Want an easy process?

This assume you are running Ubuntu.

Try this:

0. Before you start...

0.1 Ensure router power plug is secure.
0.2 Ensure LAN cable is clicked into both router and computer.
0.3 Ensure your router is working by opening (or whatever IP address you have changed it to)

1. Backup router config in case you want to restore factory firmware.

2. Factory default router to ensure it's IP address is

2.1 Power on router.
2.2 Hold in reset button until test light (tick) flashes.
2.3 Wait for router to reboot (I think - might have to power cycle it).

3. Run my script to turn on telnet, backup partitions, extract environment file, patch ADAM2 to turn off checksum test, download OpenWRT, split into 2 parts, install patched ADAM2 and OpenWRT parts...

Note: This is not conventional and may not work. But unless you have some hardware fault or power failure, you can fairly easily recover your Netgear using a Netgear image and a small C program called nftp. I'll add instructions below.

3.1 mkdir
3.2 cd
3.3 save my script here
3.4 Run my script like this: 

bash ./pc-setup-wrt-v2.bash

... and follow my instructions.

4. Boot into OpenWRT

4.1 Power cycle router.
4.2 Connect ethernet port - may take 1-2 minutes first time.
4.3 Browse to
4.4 Follow instructions to set password.


My Script

Save as pc-setup-wrt-v2.bash


# Factory default router
#   Power on. Hold in reset button until test light (tick) turns on.

# Setup PC ethernet interface use DHCP. Disconnect. Connect - should get
#   router should be

# test by pointing browser to - should get Netgear Setup Wizard screen
# route del default

# info stuff here

# MTDx partitions using 3.??.32? - seems to have 5 mtdx
# mtd0  0x900d0000,0x903e0000  ROOTFS
# mtd1  0x90020000,0x900d0000  Kernel
# mtd2  0x90000000,0x90020000  ADAM2
# mtd3  0x903e0000,0x903f0000  Probably Netgear firmware config
# mtd4  0x903f0000,0x90400000  Probably ADAM2 config

# Ordered
# mtd2  0x90000000,0x90020000  ADAM2
# mtd1  0x90020000,0x900d0000  Kernel
# mtd0  0x900d0000,0x903e0000  ROOTFS
# mtd3  0x903e0000,0x903f0000  Probably Netgear firmware config
# mtd4  0x903f0000,0x90400000  Prob. ADAM2 config

echo "Install needed packages..."
sudo apt-get install wget
sudo apt-get install expect
sudo apt-get install mini-httpd

echo "Get openwrt image - this is for mtd0 and mtd1 so it needs to be split..."

which wget || { echo "ERROR: wget not installed"; exit 1; }


[[ -f ${OPENWRT} ]] \
  || wget "${OPENWRT}"

echo "Configure this script..."

# ip address of router - should be after factory reboot

# ip address on this host - should not need to change

# port on this host that has ethernet cable to router plugged in - should be same

echo "Configure this script (ROUTER, HOST, and ETH) variables."
echo "Disconnect from all other networks."
echo "Next time you run this it will reconfigure your ETH port and "
echo "connect to your router."
echo "If you have configured variables correctly, comment out next line."
exit 0

echo "Split OpenWRT image file..."


which dd || { echo "ERROR: dd not installed"; exit 1; }

dd if=${OPENWRT} of=${OPEN1} count=720896 bs=1
dd if=${OPENWRT} of=${OPEN0}  skip=720896 bs=1

echo "Reconfigure ETH port..."

which ifconfig || { echo "ERROR: ifconfig not installed"; exit 1; }

sudo ifconfig ${ETH} ${HOST} netmask

echo "Turn on telnet - assumes your reouter has been factory defaulted..."

LOGIN="--user=admin --password=password"

wget -v -O debug.log ${LOGIN} "http://${ROUTER}/setup.cgi?todo=debug"

echo "Telnet to router, and do some heavy stuff - but nothing dangerous...yet..."

# Assign an IP address to ADAM2 (patch)
# Backup each MTD Block to RAM
# Spawn a HTTP Daemon to download MTD Backups
which expect || { echo "ERROR: expect not installed"; exit 1; }
which telnet || { echo "ERROR: telnet not installed"; exit 1; }

expect >telnet.log <
set timeout 30
set send_human {.1 .3 1 .05 2}
spawn telnet ${ROUTER};                             expect "# "; sleep 1;
send_error "Telnet script\n";
send -h "cat /proc/sys/dev/adam2/environment | grep -v \"^my\" > /proc/sys/dev/adam2/environment\r";
                                                     expect "# "; sleep 1;
send -h "echo \"my_ipaddress ${ROUTER}\" > /proc/sys/dev/adam2/environment\r";
                                                     expect "# "; sleep 1;
send_error "Cat environment file...\n";
send -h "cat /proc/sys/dev/adam2/environment\r";    expect "# "; sleep 1;
send_error "Copy partitions to tmp...\n";
send -h "dd if=/dev/mtdblock/0 of=/tmp/mtd0.bin\r"; expect "# "; sleep 1;
send -h "dd if=/dev/mtdblock/1 of=/tmp/mtd1.bin\r"; expect "# "; sleep 1;
send -h "dd if=/dev/mtdblock/2 of=/tmp/mtd2.bin\r"; expect "# "; sleep 1;
send -h "dd if=/dev/mtdblock/3 of=/tmp/mtd3.bin\r"; expect "# "; sleep 1;
send -h "dd if=/dev/mtdblock/4 of=/tmp/mtd4.bin\r"; expect "# "; sleep 1;
send_error "Copy environment file...\n";
send -h "cat /proc/sys/dev/adam2/environment > /tmp/environment.bak\r";                                                     expect "# "; sleep 1;
send -h "cd /tmp\r";                                expect "# "; sleep 1;
send_error "Start web server...\n";send -h "mini_httpd -p 1080\r";                     expect "# "; sleep 1;
send -h "exit\r";

echo "Pull files from router..."
wget ${LOGIN} -O mtd0.bin        "http://${ROUTER}:1080/mtd0.bin"
wget ${LOGIN} -O mtd1.bin        "http://${ROUTER}:1080/mtd1.bin"
wget ${LOGIN} -O mtd2.bin        "http://${ROUTER}:1080/mtd2.bin"
wget ${LOGIN} -O mtd3.bin        "http://${ROUTER}:1080/mtd3.bin"
wget ${LOGIN} -O mtd4.bin        "http://${ROUTER}:1080/mtd4.bin"
wget ${LOGIN} -O environment.bak "http://${ROUTER}:1080/environment.bak"

echo "See if correct ADAM2 versio is installed..."

which grep || { echo "ERROR: grep not installed"; exit 1; }

grep "bootloaderVersion.*0.18.01" environment.bak \
  || { echo "HALT: Boot loader version is not 0.18.01"; exit 1; }

echo "See if ADAM2 is already patched..."


which md5sum || { echo "ERROR: md5sum not installed"; exit 1; }

MDS2=$( md5sum mtd2.bin | cut -d' ' -f1 )

if [[ "$MDS2" == "d8a2f4623bf6f64b7427812f0e849aa7" ]]; then
  echo "mtd2.bin already patched"
  cp mtd2.bin ${ADAM2NEW}
  echo "mtd2.bin not patched"
  echo "Verify ADAM2 file..."
  MDS=$( md5sum mtd2.bin | cut -d' ' -f1 )
  if [[ "$MDS" != "0530bfdf00ec155f4182afd70da028c1" ]]; then
    echo "HALT: ADAM2 (mtd2.bin) MD5 sum does not match"
    exit 1
  echo "Patch ADAM2..."
  cp mtd2.bin ${ADAM2NEW}
  printf '\x00\x00\x00\x00' | dd of=${ADAM2NEW} bs=1 seek=14660 count=4 conv=notrunc 
  echo "Verify patched ADAM2..."
  MDS2=$( md5sum ${ADAM2NEW} | cut -d' ' -f1 )
  if [[ "$MDS2" != "d8a2f4623bf6f64b7427812f0e849aa7" ]]; then
    echo "HALT: Modified ADAM2 (${ADAM2NEW}) MD5 sum does not match"
    exit 1

echo "Kill off any legacy http servers (if we have somehow left them running)..."
killall mini-httpd

echo "Start local web server..."
sudo mini-httpd -p 8000 || { echo "ERROR: mini-httpd did not start"; exit 1; }

echo "Download modified ADAM2 and OpenWRT files to router and install them..."

expect >flash.log <
set timeout 30
set send_human {.1 .3 1 .05 2}
spawn telnet ${ROUTER};                           expect "# "; sleep 1;
send_error "Telnet script to install modified ${ADAM2NEW}\n";
send -h "cd /tmp\r";                              expect "# "; sleep 1;
send -h "rm mtd0.bin\r";                          expect "# "; sleep 1;
send -h "rm mtd1.bin\r";                          expect "# "; sleep 1;
send -h "rm mtd2.bin\r";                          expect "# "; sleep 1;
send -h "rm mtd3.bin\r";                          expect "# "; sleep 1;
send -h "rm mtd4.bin\r";                          expect "# "; sleep 1;
send -h "rm ${ADAM2NEW}\r";                       expect "# "; sleep 1;
send_error "Download modified ${ADAM2NEW} from ${HOST}...\n";
send -h "wget http://${HOST}:8000/${ADAM2NEW}\r"; expect "# "; sleep 10;
send -h "dd if=${ADAM2NEW} bs=1 skip=110747 count=5\r";
expect {
  "DG834" { send_error "GOOD: ${ADAM2NEW} contains DG834 string\n"; };
  timeout { send_error "ERROR: TIMEOUT: Did not get DG834\n"; exit;  };
  "# "    { send_error "ERROR: Got prompt instead of DG834\n"; exit; };
sleep 1;
send_error "Install modified ${ADAM2NEW}...\n";
send -h "dd if=${ADAM2NEW} of=/dev/mtdblock/2\r"; expect "# "; sleep 20;
send -h "rm ${ADAM2NEW}\r";                       expect "# "; sleep 1;
send -h "rm ${OPEN0}\r";                          expect "# "; sleep 1;
send_error "Download ${OPEN0} from ${HOST}...\n";
send -h "wget http://${HOST}:8000/${OPEN0}\r";    expect "# "; sleep 10;
send_error "Install ${OPEN0}...\n";
send -h "dd if=${OPEN0} of=/dev/mtdblock/0\r";    expect "# "; sleep 20;
send -h "rm ${OPEN0}\r";                          expect "# "; sleep 1;
send -h "rm ${OPEN1}\r";                          expect "# "; sleep 1;
send_error "Download ${OPEN1} from ${HOST}...\n";
send -h "wget http://${HOST}:8000/${OPEN1}\r";    expect "# "; sleep 10;
send_error "Install ${OPEN1}...\n";
send -h "dd if=${OPEN1} of=/dev/mtdblock/1\r";    expect "# "; sleep 20;
send -h "rm ${OPEN1}\r";                          expect "# "; sleep 1;
send -h "reboot\r";

echo "Shutdown local web server..."
killall mini-httpd

echo "All done."
echo "Power cycle router."
echo "Reconnect ethernet interface - may take 1-2 minutes"
echo "Browse to"
exit 0

Basic Configuration Steps

Save and Apply after each change.

If unsure, power cycle router.

Set password
Set timezone
Set dropbear (ssh) interface to lan

Edit LAN interface
  IP address (WARNING: This gives me most headaches - perhaps leave it alone for a while)
  (When you save and apply, you may need to disconnect/reconnect ethernet interface on pc)
  I set MTU to 1474

Add new (PPPoATM) interface
Set username and password
Set custom DNS servers to OpenDNS and
Assign ADSL interface to WAN

Edit Wifi
  Set SSID etc.
  Set to WEP and generate WEP hex key somehow.

No WPA???

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