halacha - What cracks disqualify a Shmurah Matzah as whole?

What cracks disqualify a hand-baked (typically Shmurah) Matzah as whole for the purposes of lechem mishneh and the Seder?

I've been told that:

1. Cracks in the center of the matzah that do not reach the edge are ok.


2. Cracks beginning from the edge of the matzah inward are not acceptable.



3. Whole matzah with a very small piece chipped off the edge are a problem.

Are any or all the above correct? Thank you.