I'll reject this update for now because of two reasons:
1) It breaks with SA-1, even if the code is SA-1 compatible;
2) For some reason, when you set the first Extension byte, when the winged Thwomp falls and the wings disappear, the Thwomp won't raise
to its original height like the .gifs depicted.
All in all, they are minor reasons. Just a quick fix and we are all set.