The device is based on Texas Instrument AR7. It uses the target.ar7 in OpenWrt.
|Version/Model||S/N||OpenWrt Version Supported||Model Specific Notes|
|TI AR7@150MHz||16MB||4MB||4 + DSL||Device Only (?)||Yes||Yes|
Flashing with the Actiontec web upgrade has not been tested. The recommended flash procedure is to use the adam2 FTP server.
To access the adam2 FTP server, power on the device while holding reset button down for 3 seconds
If you are doing this from Linux, you will almost certainly first have to:
# echo 0 > /proc/sys/net/ipv4/tcp_frto
Otherwise, the transfer process will end up slowing down to approximately 512 bytes/minute.
Note: The range you will need to flash the squashfs image to spans all of mtd1 and mtd0 partitions.
$ ftp 192.168.0.1 Connected to 192.168.0.1. 220 ADAM2 FTP Server ready. Name (192.168.0.1:user): adam2 530 Please login with USER and PASS. SSL not available 331 Password required for adam2. Password: 230 User adam2 successfully logged in. ftp> passive off ftp> quote SETENV mtd5,0x90010000,0x903e0000 ftp> binary ftp> quote MEDIA FLSH ftp> put "openwrt-ar7-squashfs.bin" "openwrt-ar7-squashfs.bin mtd5" ftp> quote REBOOT ftp> quit
Note that the power LED will not turn green with OpenWRT. This doesn't imply anything is broken as it does with the default firmware.
If you have already installed OpenWrt and like to reflash for e.g. upgrading to a new OpenWrt version you can upgrade using the mtd command line tool. It is important that you put the firmware image into the ramdisk (/tmp) before you start flashing.
cd /tmp/ wget http://downloads.openwrt.org/latest/ar7/openwrt-ar7-squashfs.bin mtd write /tmp/openwrt-ar7-squashfs.bin linux && reboot
Note: This will void your warranty!
3.3V serial is available on JP603 with the following pin out:
pin 1 : GND pin 2 : TX pin 3 : RX pin 4 : NC pin 5 : 3.3V pin 6 : NC
Pin 1 is the closest to R441.
How to connect to JTAG interface, and how to reflash the device with JTAG tools
See port.jtag for more JTAG details.
According to the documentation JTAG is available conneting to:
RESET : R106 TRST : R112 TDI : R110 TDO : R109 TMS : R108 TCK : R107
This device works with both annex A and annex B modules. As an example, to install annex B module on Backfire, download the package 'kmod-sangam-atm-annex-b' from
Then copy the package on your router per scp. Here an example using a windows client with pscp, router at IP 192.168.0.1, user 'root':
pscp -scp "kmod-sangam-atm-annex-b_184.108.40.206+D7.04.03.00-R1_ar7.ipk" firstname.lastname@example.org:/tmp
Then access your router via SSH or telnet and do:
cd /tmp opkg remove kmod-sangam-atm-annex-a opkg install kmod-sangam-atm-annex-b_220.127.116.11+D7.04.03.00-R1_ar7.ipkIf it succeeds, remove the package from /tmp. Then reboot your device.
You can check your modem stats by
config atm-bridge option unit 0 option encaps llc # Ask your ISP for the correct vpi and vci values option vpi 0 option vci 35 # Most of the time this should be set to "bridged," but some ISPs require "routed" option payload bridged config interface wan option ifname nas0 option proto pppoe option username "username" option password "password"
config interface wan option ifname ppp0 option proto pppoa option encaps llc option vpi 0 option vci 35 option username "username" option password "password"
Restart your interface by
ifdown wan ifup wan
VLANs are currently not supported.
The Actiontec GT704WG has one button. Not sure if it can be used with hotplug events.
To add hardware flow control (CTS/RTS) to the serial port on JP603 add 100Ohm 0603 resistor to R614 and R615 locations.
The GT704WG has a footprint for a MAX3232 voltage level converter. This will allow to directly connect a standard RS-232 to the router. After this modification JP603 will no longer work as the serial output is redirected to JP2 with the following pinout:
pin 1 : GND pin 2 : NC pin 3 : NC pin 4 : RX pin 5 : TX pin 6 : RTS pin 7 : NC pin 8 : CTS pin 9 : NC pin 10: NC pin 11: NC pin 12: NC material list: 1 MAXIM MAX3232 in soic-16 5 0.1uF 0603 capacitors 2 100ohm 0603 resistors 1 2x4, 2x5 or 2x6 2.54mm (100mils) pitch header instructions: 1- remove R30 and R441. These are 100ohm, if you are careful in the removal you can re-use them for point #2 below 2- add 100ohm to R147 and R442 3- add 0.1uF to C17, C18, C19, C20 and C65 4- add MAX3232 to U4 5- add header to JP2 (pin 1 is the one closes to JP603 towards the edge of the PCB)
The GT704WG uses one 128Mbit (8Mx16) PC133 SDRAM (54-pin TSOP II). The PCB is wired to support both 256Mbit (16Mx16) and 512Mbit (32Mx16). Using one 512Mbit device like MT48LC32M16A2 (or similar) your GT704WG will have 64MBytes of RAM. All is needed is to remove U105 and replace with the new chip.
The chips can be found mounted on old PC133 DIMMs or SODIMMS. 128/256Mb DIMMS with 4 chips are the best candidates.
I have done the modification using a generic 32Mx16 SDRAM (no brand). The Adam2 installed on my router will reset the memsize environment variable at every reboot so the mod will be useful only when using kernels with memory size auto detection (the stock firmware will not auto detect the memory size). OpenWrt will correctly size the memory regardless of the env settings.