OpenWRT build for DIR-615 with USB mod (described here: http://wiki.openwrt.org/toh/d-link/dir-615/ex-usb ). My own modification includes USB mod and minimal set of software to boot from flash drive. Tehere's also most of standart packages to work without flash for most popular cases. You can download binary images (in "release" directory) to flash them in recovery mode (described here: http://wiki.openwrt.org/toh/d-link/dir-615#installation ).