So is it possible to use 12v (with enough current, ofcourse..) with this motor although it says 1.24vdc on it? I was thinking about using parallel sn754410ne with the old version of the motor shield (about 6 of those..) in order to handle the current. will that do?
I repeat "the voltage is not relevant, steppers like this are current driven"
You'd probably use 24, 36, 48, or 72V in practice to get high performance. Forget the voltage rating, this
is a 5A motor with 1.24mH of winding inductance, those are the critical parameters and they mean this
motor can go really fast (3000rpm or more) with a high enough supply voltage. The inductance and
motor back-EMF are what determines the voltages involved, the winding resistance is utterly swamped
by these other sources of voltage.
You use a chopper driver with this motor only, it is current driven.
Another question, is 5.4Amps the total amount of current needed or do I need 2X5.4amps (as I have 4 wires I guess there could be 2 currents in parallel)?
That's the amplitude of the 2-phase AC current waveform, you don't need to worry about that,
that's what the chopper driver takes care of. You need to worry about the current into the chopper
driver which is a complex function of the supply voltage, motor speed and load! It could be
less than 5A even.