Can I make my own footswitch for MicroPro amps?

Each of the 6 control lines has a 3ma current-limiting resistor tied to +15V. (The 7th line is reserved, and the 8th line goes to ground). Each current source goes to an LED which is shunted by a latching footswitch. In the "active" position the switch is open, the LED glows, and amp circuitry detects the +1.5-2V voltage on the LED. (This generally triggers the same amp behavior as the default "footswitch unplugged" state). When the switch is closed, the LED goes out, and this triggers the amp to bypass the effect (tremolo OFF, for instance).

 You can make an adapter to switch any of the MicroPro's functions using a basic on/off switch. 

The MicroPro foot controller works by grounding a 15V, low energy voltage to the ground pin on the RJ-45. If you cut off one end of a standard CAT5 or CAT6 network cable, you can use the chart below to see which wires need to be connected to your switch to bypass each function. 

MicroPro 200 foot controller pinout:
PIN 1 - Orange/White - Boost
PIN 2 - Orange - Limiter
PIN 3 - Green/White - Tremolo
PIN 4 - Blue - Reverb
PIN 5 - Blue/White - FX Loop
PIN 6 - Green - Mode (*requires 1k resistor from Pin 6 to ground. Only necessary on Gen 1 MicroPro.)
PIN 7 - Brown/White - NOT USED
PIN 8 - Brown - Common Ground

NOTE: These colors are only for a standard network cable, the Quilter supplied footswitch cable uses a different color coding pattern.

So if you want to switch the boost function, simply connect the brown wire and Orange/White wire to your switch. 

The mode switching is slightly more complicated because the default state of the function is to be active when the footswitch is disconnected. The Mode LED in the foot controller is a necessary part of the circuit and the mode function will not switch without the LED in series or a 1k resistor in series. 

No harm will come to the amplifier as long as the switch simply makes and breaks connection and does not inject voltage into the cable.