Ricoh firmware CRC -- how to recalculate?

[max bashirov]

Here
http://cdmediaworld.com/hardware/cdr...coh_7040.shtml
(Upgrade a Ricoh RW7040A/S to a Ricoh MP7040A/S)

was described model reflashing procedure with the following note:

"By modifying the MP firmware by replacing the MP model number for the RW model number and *recalculating the CRC* the flash software will think it is a valid firmware."

I have AOPen CRW2440 with firmware 2.09 from MET CQ2440 and
need to change strings in bin-file so that drive can be recognized as AOpen again.

Where I can get utility (or at least algorithm/description) mentioned above to perform firmware file CRC recalculation? Article has no details on it...