What format is this image *really* in?

[Sir Teatei Moonlight]

Btw this is the usual order for storing a bitstream as bytes.

All the other BCn formats (well, BC1-5) seem to function properly when read with no byte reversal. I wouldn't have gotten stuck here if this made sense.

Unless the code I have working for them is secretly doing it in the background without being clear about it. That's a possibility.

It seems like you could just copy/port an existing decoder. bc7decomp.h / bc7decomp.cpp from bc7enc has essentially no dependencies if that's the problem.

I'm using Python in Blender. It's honestly easier to do it from scratch using references.

EDIT: I am getting improved results now, you have helped unblock me.