I asked the seller that very question by email yesterday. Today I received a reply.
He said, that he bought the board second hand while it was broken already.
The seller has not contacted Intel and as far as he knows, the previous owner did neither.
He suggested me to buy the board and contact Intel by myself.
Well, that all sounds pretty weird. On the other hand, the broken board is a real bargain.
By the way, he has given me the following details:
SN = BTDF21500047
Batch = CNBT24E01P
Is there anything I can check?
EDIT: Hi, I've just spoken with Intel Customer Services.
A man said that I will not be able to use the warranty as it's only between the original buyer and Intel.
He suggested to not buy the board.