The part 1 is of the algo is understanding the serial (thanks to Remix)
The serial number looks like this:
6144526 84302
the serial number is formatted (LNNNNNN YWWFF)
L the number of the production line within the factory,
NNNNNN the number of the Xbox within this week.
Y the last digit of the production year,
WW the number of the week of the production year
FF is the code of the factory (02: Mexico, 03: Hungary, 05: China, 06: Taiwan),
So taking the serial number 6144526 14302 this would give us
Line 6 of the factory
This would be 144526 off the production line
2008 production year
Week 43 of the year
Factory location Mexico
2nd Part - The Algorithm itself
The serial number is a value, so whenever you add or take away from the value the serial becomes invalid.
i.e. 121212121212 = 18 Valid, 121312121212 = 19 Invalid.
With using the guide above you can edit the numbers 6XXXXXX84302
When ever you change a number, e,g. 5 -> 3. thats -2 in the value, which means you must +2 to another number to make the serial valid value again.
