I've installed DDWRT on the DIR-615 but I don't see any option to change it to repeater when I go into wireless basic settings though I can see the option to put it into AP or client mode for example. I also don't see the Network Configuration : Bridged option.
I read somewhere that the chip-set in this router is not capable of the repeater function that is why its not showing up in the drop down list. however there is a work around that i have been playing with. I have the same router and I've purchased it without knowing this also. Trick is to select client mode of some sort and then create a virtual wireless interface to rebroadcast the signal locally. I've successfully been able to use the router as a repeater bridge to share internet connection. I have not done any speed tests but i know that it does work. DIR-615 Hardware revision C1. Waiting for my pigtails from eBay to mod the non removable antennas as well.
I have also set my dir-615 up as a bridge routed and added a virtual interface but when I access it it allows me to hit like 2 web sites then I get a web page not found when I attempt the 3rd website? Any thoughts?