About EMS Cartridges
The EMS cartridge has a second set of storage for ROMs. To access pagefile two, follow these steps:
1. Plug the cartridge into your Game Boy and turn it on.
2. Turn the Game Boy off after a second or so.
3. Turn the Game Boy BACK on again.
If you did it correctly you will see a green light turn on inside of the cartridge. If you do not see this green LED, repeat steps 1-3 until you succeed. It takes a try or two if you've never done it before, so be patient! =)