The 20D firmware (v.2.0.3) can be found on Canon's website:
http://web.canon.jp/imaging/dc/eos20d203.exe (windows self-extracting)
http://web.canon.jp/imaging/dc/eos20d203.hqx (mac os self-extracting)
alternatively, the extracted file can also be downloaded from http://www.zshare.net/download/6714237d102c6a/
-- CAFxX