I can’t find the way to type PgUp/PgDn/Home/End key with GemiBook.
CHUWI should provide a BIOS update that fixes it using Fn + arrow keys:
Fn + up arrow = PgUp key
Fn + down arrow = PgDn key
Fn + left arrow = Home key
Fn + right arrow = End key
It is a huge design flaw not to have included those keys