can any1 point me in the right direction of working out the crc of the dump ?

ive been playing around with the format for a while but stumped everytime

ive tried a few diff programs but no joy

also if im correct is the crc the last couple of bytes at the end of the dump ?

bin playing around with chaning the netid in the dump but cant seem to get the crc right to follow, box just keeps rebooting.
i know i can do it all with a funcard or simply program a fun card to do it, but trying to educate myself here


thanks

dave