I have been working in other adaptation for inet 4 and I have been more aggresive in my changes, I have changed most of the packets to Chunk type, if you want my files to check my approach I can send you.
There are several things that are not correct, one is the header compress, the other is the fragmentation, I am not sure if it works correctly.
Other thing that I am no sure is the header sizes. There are many headers with size 0, but if you use chunks, the header should have at least a byte.