Install latest DD-WRT v24 release candidate (but not RC6.2! v23 doesn't support repeater modes). Visit the UWR forum for test results on firmware versions. Keep ethernet cable connected for these instructions (to have connectivity across wireless network changes).

Use DD-WRT To Make Your Router Into An Access Point Apr 20, 2009 Get More Out Of Your DD-WRT Router With An External Drive The script tries to use the –passive-ftp switch with wget, but the DD-WRT built-in doesn’t accept it, which leaves the entire thing broken. cp /bin/ipkg /usr/local/bin and now you can edit the script and remove the –passive-ftp switch. While you’re editing files, you’ll want to look at /etc/ipkg.conf. How To Extend Your Wi-Fi Network With An Old Router

Here are the detailed install instructions, but with most Linksys routers, you can just drill into the router settings from the web address (192.168.1.1) and upload the DD-WRT firmware, directly

Keep Your Router Secure: Change These Settings | Lifehacker UK

DD-WRT should select the Basic Settings sub-tab by default, but if not you should click on it. Find the Wireless Channel drop-down menu and select the channel you want. Click Save, then click Apply

DD-WRT Forum :: View topic - E3200 now a Repeater/Bridge help