Hi, like cheche I am also using ddwrt right now on my two DIR615s, but one is my "experimental" router.
My goal is to have both wireless and IPv6 (using aiccu&radvd) on the second router, and because of the wireless drivers I'm kind of stuck with ddwrt...
Right now I am modifying brainslayers ddwrt builds to get IPv6, but I just can't seem to get a image capable of booting [I just enter infinite reboot loop]
So my question is: How is your initial openwrt-ramips-rt305x-dir-300-b1-squashfs-sysupgrade.bin in step 10 composed?
The SDK creates the input file for v2image out of a stripped/compressed/header-added kernel image and the rootsquashfs, but for me that does not work with custom ddwrt kernel and modified ddwrt rootfs (I unpacked the one cheche linked and added IPv6 modules and removed some daemons I do not need to get below 3.8Mb).
I created a build script based on the SDK build scripts, but I think the OpenWRT tools are way better (and most important: working)
But if you wan't to see: http://www.dd-wrt.com/phpBB2/viewtopic.php?t=77040
Maybe I will try to focus on OpenWRT, as I don't need a nice GUI for the second router (only primary one has that requirement as it has to be used by some of my flatmates as well), but I'm afraid I'm not a big help in porting old kernel drivers...