Some comments on the youtube video suggested that it's not a CRC but a simple 8 bit checksum that must add up to '0'.
If that's true, it effectively doesn't matter which byte you pick as the checksum byte. Of course, you would not want to randomly pick a calibration value
Somebody suggested the second byte (0xDC) is the content length, and that the last byte at offset 0xDB is the actual checksum byte.
I hope the solution is obvious now: If you don't know where the checksum byte is, just modify a value that you definitely know can be changed with no harm: Just modify _two_ bytes of the serial number, increase one, decrease another one :-D