After a little dig through past posts here is an example of the previous keyroll.
This decodes to
This effectively computes the signature of a chunk of Rom10 code starting at Rom address $5E94 and then uses this signature as the DES encrypt key to change the data in the bytes dump to the real key0/key1 used for video decrypt !
So, for this type of keyroll the whole ROM10 ROM code has to be available for reference !