Upgrade BUFFALO DD-WRT firmware

I know the BUFFALO has update the new DD-WRT firmware in Hong Kong Official Web Site for a long time. Until today, I am a little free so that decide to do this job.

To connect this AP with my notebook by network line, key in its management IP “192.168.21.1” in Opera URL. The main screen will show up and its firmware version is “DDR-WRT v24SP2-MULT1 (10/31/11) std”.
To click “Administration” link
To key in username and password in authentication window
If the authentication is successful, you can set or change the configuration and parameter now.
To click “Firmware Upgrade” link
To click “check for Upgrades” button
The available Updates information will show up.
Please first click “releasenote_whr_hp_q300n_ddrwt_tw.html” to study readme file.
In this content, you will understand the firmware version will be upgraded to V24-SP2 build 19152 and this version add what is new feature.
To select “chose” option and click “Upgrade” button for executing Online Updates process.
Upgrading firmware …
Upgrade successful and Unit is rebooting now.
The firmware version has already changed to “DD-WRT v24SP2-MULT1 (04/27/12) std” now.