Installing dd-wrt firmware on Japanese routers

DD-WRT initial information page displays 99% of the information many people are seeking when accessing their router:
WAN IP, WLAN clients, and DHCP clients

If you've ever used a Japanese router, then I don't need to explain to you what is wrong with the firmware. Lack of English is over shadowed by the lack of functionality and organization. Before delving into a Japanese router, I do my best Clint Eastwood and chant "Think i-mode". Even so, doing something simple like cloning a client MAC address - or even displaying a list of connected clients - can be infuriatingly, ridiculously convoluted and painful. At best. At worst, stuff that should work simply doesn't and functionality that should be there just isn't.

Buffalo's router firmware landing page is both useless and ugly.  

Fortunately, there is dd-wrt.

dd-wrt is a third party router firmware that is compatible with a large number of makers. Not only does it not suck, it also offers the choice of multiple languages. The router database can be checked for models that are compatible, but since model numbers and hardware revisions often are slightly different across regions, don't expect to find many (if any) Japanese models listed.

It seems the best chance of support for the routers commonly available in Japan is Buffalo, though there may be some issues. Of the other routers available at Yodobashi, such as Logitech, NEC, I-O Data, and Corega, none are found in the dd-wrt database. Only one Planex router is in the database. This doesn't necessarily mean it won't work, since it's less the maker and more the chipset, but the firmware would likely need to be ported.

One of my routers, the Buffalo WHR-G301N is apparently the Japanese version of the WHR-G300N v2, and can be upgraded to dd-wrt by the same instructions. Some Buffalo routers actually shipped with dd-wrt preinstalled as a "pro" firmware. As far as I've seen, all Buffalo routers in Japan have the "junk" firmware preinstalled.

Read on to fix this "bug" for the WHR-G301N.

WARNING: This will void warranty and potentially brick your router. Proceed at your own risk!

1. Downloads

There are two files that are needed:

1. buffalo-to-dd-wrt_webflash-MULT.bin
2. whr-g300nv2-firmware-MULTI.bin

The first file, buffalo-to-dd-wrt_webflash-MULT.bin is need to flash dd-wrt from the web interface when Buffalo firmware is installed on the router and should be all you need. The second file is what is used when upgrading this router from another version of dd-wrt.

However, the latest version (06-08-12-r19342) results in an Incorrect Firmware (ファームウェアデータが正しくありません) error. I used the same file found in this blog entry: from the 2011/06-14-11-r17201 build. So, I first flashed an older version of dd-wrt, and then upgraded to the latest version, which is available here:

http://www.dd-wrt.com/dd-wrtv2/downloads/others/eko/BrainSlayer-V24-preSP2

Click through to the latest version by, currently 2012/06-08-12-r19342, and choose buffalo_whr_g300nv2. Download the latest whr-g300nv2-firmware-MULTI.bin file.

2. Bypass Buffalo Protections

Assuming you've made no changes from the factory defaults, login to the WHR-G301N administration screen at 192.168.11.1 with username root and no password.

Next, click the administration settings tab (管理設定), and click the firmware update (ファーム変更) tab.

Is this Amateurish CSS and html or do the subtabs only render properly in IE 6?

My firmware version is WHR-G301N Ver. 1.82, and from what I can tell, there are unlikely to be any updates to this. From update method (変更方法), choose local file (ローカルファイル指定), and select the whr-g300nv2-firmware-MULTI.bin from the older build directory.

If all is correct, you'll get the following screen. While it's completely unnecessary, I've decided to translate this into English, since some of what's written is totally ridiculous.

Even this is ugly.

ファームウェア変更中です。
DIAG-ランプ点滅ちゅうは電源を絶対に切らないでください。
あと約180秒、お待ちください。
その後、設定を続ける場合は、次の手順を行ってください。

1. WEBブラウザーを全て終了してください。
2. お使いのパソコンとエアステションが通信できる設定になっている事を確認してください。
3. ユーティリティーからWEBブラウザーを起動してエアステションのWEB設定を行ってください。

ユーティリティーの使い方はマニュアルを参照してください。

Updating firmware.
Be sure not to turn off the router until the diag light stops blinking.
Approximately 180 seconds remaining.
Do the following if continuing to update settings.

1. Close all web browsers. [like this is necessary.]
2. Confirm your PC has a connection with the router. [Ok, this is good advice]
3. Start the web browser from the utility disk and run the web settings application [Totally unnecessary.]

Consult the manual for instructions on running the utilities.

3. Confirm settings

After that, the router should be reset with dd-wrt firmware installed. You may want to reboot the router. From the initial screen below, you can see that, right there on the welcome page, is exactly the information I want to see: that I have no WAN address (because I'm not hooked up to a simple DHCP Server)

I didn't bother changing the password right away. I first setup my WAN to make sure I had an internet connection, then jumped over to admin/firmware to upload the latest version.

4. Upgrade to the latest firmware version

Select the whr-g300nv2-firmware-MULTI.bin file you downloaded from the most recent build folder. When upgrading dd-wrt, there is a nice option to wipe all settings after flashing or leaving them intact.

5. Set up for Japan

I really like that dd-wrt allows you to set the "regulatory domain" to enable and disable features based on local laws. Of course, you have to trust that the maintainers of dd-wrt got this correct.

From wireless/basic settings, check the advanced setting box, and select Japan as the regulatory domain. Doing so enables two additional channel width settings, Turbo (40 Mhz) and Dynamic (20/40 MHz), as well as channel 14. As far as I can tell, this is appropriate for Japan. To take advantage of this increased bandwidth, you'll need to set WPA2-AES security. (NOTE: Android seems to need AES+TKIP.) However, if there are many routers in your area, doing so my actually decrease performance, since the needed bandwidth may not be available.

Also, channel 14 is only used for 802.11b in Japan, and should technically be unavailable when enabling only g and/or n. This is not the case, so using channel 14 could cause all your gear to fall back to 11 Mbps b speeds.

Another potential issue is the transmission power. I've read elsewhere that the initial setting of 20 dBm is in excess of Japanese denpa-hou and should be lowered to 10 dBm.

電波強度を下げる
日本の法律に従い、無線LANの送信出力はちゃんと10dBmに下げましょう。（初期設定だと20dBm)

I've been unable to confirm this. I've been passed a link to an MIC page showing that, in the 2.4 GHz range, power needs to be under 35 µV/m. Here is a page on calculations (PDF). Enjoy.

According to wikipedia, 10-15 dBm is around the range of a typical notebook computer's wifi transmitter. In general, it is probably best practice to set the power to the lowest possible level that gets you decent coverage in your area. This not only reduces the chances of unauthorized access to your network, but will also interfere less with your neighbor's wifi.