Actually, it needs to be embedded in the exth 113 field -- inside the Palm headers of the ebook.
The Quality Check plugin has an option to "Fix ASIN for Kindle Fire", and is often used to embed fake ASINs, in order to change a "Personal" document (darn that stupid banner to heck
) into a "real" book (whatever Amazon thinks that is
).
I think it can also be used to reset the existing ASIN (but I don't remember if it is optimized to not bother when there is already an embedded ASIN).
...
What that does, is make Amazon no longer know that the book came from them. It is a bit of a brute fix -- my curiosity would rather know what was wrong in the first place!