Hi, sorry for keep drilling the subject.
When they said cut the common wire, does it mean physiclally remove the common wire from one winding to the other from the tiny PCB, so that the two windings are completely independent from each other? The reason I am confused because as is (without cutting the common wire). it works only one direction when I follow this tutorial:Overview | Arduino Lesson 16. Stepper Motors | Adafruit Learning System but I cannot get it to work on the Pi.