You're using the same processor as the NoteAir3C.
There is this thread
https://www.mobileread.com/forums/sh...d.php?t=357326
They were having trouble with finding a loader that worked and then suddenly all of them worked.
I don't know where the confusion/randomness came along.
Try using that same factory SDM662 file.
If you have a Windows box hanging around I'd rather work with my software than the Python stuff.
If you can't get a loader to work then we're stuck waiting around until an update is released.