I've use OpenWRT for my D-Link DIR-620 A1 for almost a year now. Good news that OpenWRT community released already compiled beta versions (Latest for now is 12.09-rc1) So now it's no need to compile trunk sources to get firmware for ramips hardware. My custom image is getting old, so I decide to install latest community release.
This article is mostly for myself. Just want to leave some notes in case I'll need to update firmware again. So I'll make it very brief.