From DD-WRT Wiki
 Important Notes
Only version 1 is supported. Versions 2 & 3 are not yet supported.
Use only K2.6 builds with nv64k in the name.
Read Peacock topic (at top of Broadcom Forum). Read it all. Carefully.
 Hardware Specs
|CPU Speed||480 MHz|
|Flash ROM||8 MB|
|Radios||2.4 GHz and 5 GHz|
|WLAN Max Speed||300 mbps on 2.4Ghz and 300mbps on 5Ghz|
|Switch||4x 100 LAN + 1x 100 WAN|
|USB||1x USB 2.0|
 DD-WRT Installation
- There are two versions of this router with corresponding initial flash mini firmware. One is for Netgear branded routers and the other is for Cablevision routers.
- Do a factory reset (recessed button in the back), and upgrade with the appropriate mini firmware above. If it complains about downgrading, just Allow.
- To gain functionality of the usb port, upgrade to the big version or the mega version after flashing the mini version above.
- 30-30-30 reset router (as described in Peacock).
 Build Notes
- This is a good build for this router.
- Upgrading to 21676 Big will brick this router! Use 21676 Mega instead.
- This is otherwise a very good build for this router.
This router can be "bricked" (rendered inoperable) by flashing the wrong firmware; by not following the correct flashing procedure (in Peacock); or by flashing a bad build like 21676 Big.
 Factory method
 Recovery mode method
This method, which works on the WNDR3800, may also work on the WNDR3400v1.
 Pin short method
- Timing of the pin shorting is tricky -- power on, wait for the lights to flash, then try shorting a few times until the power light starts flashing steadily.
- Next use tftp2 (with no password) to flash factory firmware.
- After the flash, wait at least five minutes after the router boots up and the power light becomes steady green before resetting the router.
 Revert to Factory Firmware
- Download official Netgear firmware
- Reset DD-WRT (recessed button in the back)
- Enable telnet under services
- Telnet to router (192.168.1.1)
- Issue the command "mtd erase linux" & wait ~3 mins
- tftp the official firmware to the router
- tftp for windows  enter router ip, leave password blank, select official firmware file
- 30-30-30 reset router (as described in Peacock)