Well, to inform you, your SA-1 conversion was quite wrongly done, due to bad sprite table conversion; however, I fixed it for you. Other than that, nice block, and it works, so accepted. I'd like to point two things, though:
1) The place you update the colors in palette 7 is not the best appropriate. You could move it to the last 8 colors of the palette row (not a removal reason, since it's GFX related);
2) Your code activates dead bob ombs. A previous $14C8,x check could be made if it was not your intention.