After having changed the steps/mm in the firmware, have reset the values to the (new) defaults and stored them into EEPROM? This can be done via display menu or by sending manually the gcodes M502 followed by M500.
As for the micro stepping changes not having any effect, note that there are some RAMPS boards around which have the jumper pins shorted on the PCB, so that the jumper settings have no effect.
As for the micro stepping changes not having any effect, note that there are some RAMPS boards around which have the jumper pins shorted on the PCB, so that the jumper settings have no effect.