qi boot into third partition

[Peter Fey]

Hi,

I have three partitions on my sd-card and each of them contains a
bootable system. How do I get qi bootloader to boot the system in the
third partition?
Booting first partition is just pressing and releasing power.
Booting second partition is pressing power, releasing power, pressing
aux, waiting for vibration, releasing aux.
But what to do to boot into the third partition?

Peter