Yes there is a way. It was discovered by vettefan88 but it was never released to the public. Maybe you could be the one who solves this ever huanting mystery for us all? I've gone as far as knowing what parts of the file hold what info and that the file is an encrypted 2ds (or a dds? I dont remember its been a while...) file.
@Asg16_4 I've had so many issues with the unpacking process on newer Windows systems. The only way I've gotten it to work EVERY time is to drag all of the .map and .big files into one folder on the desktop, and then run the unpacking script in that folder. When it's done, drag the unpacked folders where they belong in the TDU2 main folder. At that point, make sure your backup is in a proper place and you're good to go!
As I said, I've had HUGE frustration before and I think I'll make a thread on this right now..