(For the sake of completeness I've added a copy of my PM here as well.)
Hi,
I've implemented my own GR2 reader to make sure that the tool is as free of patents (and as legal) as possible. It currently only requires granny2.dll for Oodle0/Oodle1 (de)compression (which is only used by ~0.5% of Divinity 1/2 assets). It targets Granny version 2.8.49 though, and is not really meant to read customized formats of other games, so it fails to read the example file you provided. I'll check what can be done to make it work.
The code for reading GR2 files is available here:
https://github.com/Norbyte/lslib/tree/master/LSLib/Granny/GR2
