So this was nearly two-three months of work for me... but I was able to create a program that converts a G1M file from big-endian to little endian, over 2500 lines of hand written code. I couldn't have done it without a lot of help though from various sources - as some sources were errant in some of their findings but not most.   Anyways, with this program you can take a Big Endian G1M file and drag and drop it into the exe and it will create a `_converted.g1m` version of the file.