From DD-WRT Wiki
The D-Link Xtreme N Dual Band Gigabit Router (DIR-825) uses dual band technology to support 2.4GHz & 5GHz wireless signals at the same time. This allows you to check e-mail and browse the Internet using the 2.4GHz band while simultaneously streaming High-Definition (HD) movies and other media on the 5GHz band. The DIR-825 is designed for users looking to get a true HD wireless connection that can handle multiple HD video streams throughout the house, while being backward compatible with existing 802.11g and 802.11a products.
|CPU||AR7161 680 MHz|
|Radio (2.4 GHz)||AR9223|
|Radio (5 GHz)||AR9220|
|Antenna Type||External (Dual Band)|
|Number Of Antennas||2|
|Antenna Gain (2.4 GHz)||2 dBi|
|Antenna Gain (5 GHz)||2 dBi|
|Max TX Power (2.4 GHz)||19 dBm|
|Max TX Power (5 GHz)||17 dBm|
|Antenna Chains (TX/RX)||1+2/1+2|
- Max TX Power assumes used regulatory domain is Canada/USA/Haiti. Others may or may not allow higher TX powers (up to 30 dBm).
 Installation Instructions
 Step-by-step instructions from out-of-the-box factory firmware
To install dd-wrt on a D-Link DIR-825 you can flash it directly from the router's web admin page (yes, that is correct... from D-Link's standard web interface). These are the steps to follow:
1. Download the correct factory to ddwrt firmware for you router: NA (North America), TW (Taiwan), or WW (World Wide, any place other than NA or TW) which can be found below, these are for unit revisions B1 & B2 ONLY.
Webflash (all regions): ftp://ftp.dd-wrt.com/betas/2017/03-21-2017-r31722/dlink-dir825-revb/dir825-firmware.bin
1b. These ones for unit revision C1 ONLY.
2. Set your IPv4 network adapter to the following in your windows network configuration to: IP Address: 192.168.0.2, Subnet Mask: 255.255.255.0, Gateway: 192.168.0.1
3. Physically connect the router ethernet port #1 to your computer ethernet port (NO WIRELESS!)
4. Perform the 30/30/30 procedure:
- With power on, hold the reset button down for 30 seconds.
- Without releasing the reset button, unplug the router. Continue holding the reset button for 30 more seconds.
- Without releasing the reset button, plug the power back in and continue to hold the reset button for 30 more seconds.
- Release the reset button. The power light should be flashing on and off orange.
5. In Internet Explorer or Firefox enter http://192.168.0.1
- Note: Sometimes you need to set IE to IE7 compatibility mode to make your router accept the new firmware.
6. You should see a screen titled "Firmware Upgrade System"
7. Select the "factory-to-ddwrt_XX.bin" file you downloaded and click the Send button to flash your router. As the firmware is uploaded and installed you will see the screen start counting to 100 percent. The power light will remain out during this process. At 100% the power light the power light will flash yellow and the router will reboot. The router globe will be yellow, the power will be blue, the 2.4/5GHz will be flashing blue.
8. Remove the static IP from your computer network settings.
9. Using Internet Explorer or Firefox go to: http://192.168.1.1 and You should see the DD-WRT screen to change your password.
10. You should now be at the System Information screen.
 How to upgrade with new DD-WRT firmware
1. Download the latest "dir825-firmware.bin" firmware upgrade file from the same FTP server as the initial flash files above are found. Go back to parent directory and use the latest posted build and then go back to the "dlink-dir825-revb" folder and take the -firmware.bin file.
2. Open the DD-WRT's web interface in your web browser. It's http://192.168.1.1/ by default.
3. Administration tab -> "Firmware Upgrade" button
4. Click "browse" button -> select the "dir825-firmware.bin" file -> click "Upgrade" button. It will take about 2 minutes to upload and write the flash. Your browser will reload and let you know when it is done.
5.It is probably a good idea to reboot after updating. That's it.
 How to restore to factory firmware
- Download the stock firmware at
- Set your IPv4 network adapter to the following in your windows network configuration to: IP Address: 192.168.0.2, Subnet Mask: 255.255.255.0, Gateway: 192.168.0.1
- Physically connect the router ethernet port #1 to your computer ethernet port (NO WIRELESS!)
- Perform the 30/30/30 procedure, using the same method you used to flash DD-WRT firmware.
- Using Internet Explorer or Firefox go to: http://192.168.0.1 you should see the stock "Firmware Upgrade System" screen.
- Select the stock firmware that you downloaded in step 1 and click the Send button.
- Remove the static IP from your computer settings 1 minute after clicking send.
- Using Internet Explorer or Firefox go to: http://192.168.0.1 and You should see the D-Link screen, leave the username "admin" and the password blank to log into the router.
 Common Problems
These issues do not affect most, & do not seem to be happening anymore with the latest builds.
1. Dramatic reduction of WAN download speed over time.
- Reboot temporarily clears the problem.
2. Web GUI slows slowsmdown and becomes unresponsive over time.
- Reboot temporarily clears the problem.
- Support Thread: See Forum