Kirby and the Amazing Mirror fail to communcate with minigames using Single Pak Mode

[Testsr]

Reproduction steps

1. Boot one GBA with Kirby and the Amazing Mirror, and the other with BIOS.
2. Select a minigame, Multiplayer and when the other GBA is detected, press A to connect.

What happens:
The minigame transfers properly, but the Level selector never appears, and the games displayes the communication error screen after a second.

This bug has been tested on master branch, and new-sio branch.

[Testsr]

Will have bug report txt in a day or two.

[Testsr]

Also as a reminder, the four player bug on KaTaM needs to be addressed.