I wired up the keypad again, according to the sparkfun tutorial, but I had to made a few changes in the code for put the keys in the right place.
Buttons 1, 3, 5, 7, 9, * and # are operational, yet the same 2, 4, 6, 8 and 0 not working!
Is it possible the keypad it's damaged?
I bought it yesterday!