WallabyPatch loader is an sdcard image, with header 'HTC$WALLABY33'. which is automatically loaded and executed by the WallabyBootloader.
source is in cvs. (U R L to CVS seems to be wrong! ? / wbt-1.5.zip Download link on this page Link has the Sourcecode included)
http://wiki.xda-developers.com/uploads/wbt-1.5.zip