LEGO Games v2

"
Security:
-> Custom Checksum
   -> Offset: 12
   -> Calculation Start: 16
   -> Calculation Length: Size - 16

Additional:
LEGO Hobbit and newer use the same checksum, but store it at 16 and the calculation start is 20.
"

private int CalculateChecksum(byte[] data, int offset, int size) {
    int sum = -1;

    for (int i = 0; i < size; ++i) {
        sum *= 0x1000193;
        sum ^= data[offset++];
    }

    return ~sum;
}