1) An Official Nintendo Game Boy Micro Game Link Cable.
2) Any Gameboy Advance to Gamecube Link Cable. The directions below show how to use the following link cables:
- Official Nintendo Gamecube to Game Boy Advance Connector Cable
- Nyko CubeLink cable
- MadCatz SystemLink cable (For both GCN & GBA connectivity via the GBM)
3) Soldering skills
for the nyko cable go to step 3
Step 1: Official Nintendo Gamecube to Game Boy Advance Connector Cable Directions
Please note that I've only stripped the wires a tiny bit. You'll see why in the next step.
Step 2: Next
After you've finished this, you can try to stuff it back into the GC connector housing. If you do, be sure to cover your work with electrical tape and provide some strain relief on the cable. I end up using a small project box to enclose the electronics.