Report as inappropriate

Looking at the board layout and the schematic for your board: https://github.com/Ultimaker/Ultimaker2/blob/master/1091_Main_board_v2.1.1_(x1)/Main%20Board%20V2.1.1.pdf

It is a surface mount PCB with the drivers soldered onto the board, Depending on your soldering skills? it may be tricky for you to solder to the A4988 driver or the MEGA2560 to access the DIR and Step signals (Step is Pin 6 and DIR is pin 9 on the A4988 drivers highlighted on the attached image), you may not need enable as you can hard wire the CNC drivers to always be enabled.