Hi Kfir,
I’ve never really had issue with these but I’ll go ahead and ask the obvious question first – did you remove the bolt? It’s hidden under the model/serial# tag on the neck block.
Beyond that I would simply suggest to keep at it. I’ve been able to remove them pretty easily with both steam and now adays the foam cutters.
Cheers,
Doc
Edit – Ian let me know he believes through photos you’ve shared with him that the bolt has been removed so perhaps trying to pull outwards by clamping the neck and lightly shifting the body back and forth and pulling outwards. The fingerboard extensions and part of the joint are glued. I believe these are mortise & tenon joints (you should be able to confirm by looking at the specific model on the Martin website) so pulling outwards is another possible solution compared to the upward removal of a dovetail…
Edit Edit – Ian beat me to the last Edit so, yha, what he said…