On the Subject of Colorful Madness
I hope you don’t have chromophobia!
Take the 1st, 3rd and 5th characters of the serial number.
These will be your main 3 characters.

If any of your main 3 characters is a letter, convert it to a number:
 Where A = 0, B = 1, C = 2, D = ... etc.

If there are any buttons with both red and yellow colors:
 Add the number of batteries to each of your main 3 digits.

If there are any buttons with 4×4 checkerboards:
 Calculate the difference between the number of such buttons and the number of ports.
 If the number you got is negative, get rid of the negative sign.
 Subtract that number from each of your main 3 digits.
 If any of your 3 main digits is negative, get rid of the negative sign.

If there are any squareonsquare buttons:
 Multiply each of your main 3 digits by the number of battery holders plus the number of port plates.

If any of your 3 main digits is greater or equal to 10:
 Subtract 10 from it until it’s smaller than 10.

If the 1st main digit is equal to the 2nd or 3rd main digits:
 Add 1 to the 1st digit until it’s not equal to the 2nd nor 3rd digits.
 If the 1st main digit reaches 10, convert it to 0.

If the 2nd main digit is equal to the 1st or 3rd main digits:
 Subtract 1 from the 2nd digit until it’s not equal to the 1st nor 3rd digits.
 If the 2nd main digit reaches 1, convert it to 9.
 Add 1 to each of your main 3 digits.
 Positions are determined starting from the topleft, going lefttoright and toptobottom starting from number 1.
 Finally, press the buttons in the positions indicated by your 3 main digits, alongside with their counterparts that have the same pattern but with the colors reversed.