Actually I have selected motherboard 92, dived into the source to see how the M907-M910 work.
Tried several values, stored in eeprom but still can't get the motors to move at all.
I'm out of ideas...
Actually this board is named as Pirxboard, which is supposed to be based on the printrboard revf. Also downloaded the schematic of the board and the pin mapping is identical.
However I'm leaning towards the fact that this is not the case and pin mapping is different as I noticed it is not only the motors not moving.
I'll try to trace the pins on the board itself and get back with more info.
Thank you for the help.