Hold the listed key while powering on the tablet.
ESC: Boot device selection menu
DEL: Boot into BIOS Setup (same as F2)
F2: Boot into BIOS Setup
F9: Boot into windows recovery mode
F12: Not sure what this is, it briefly flashes "Launching FFU.efi" then print "Main Start" and sits there
Vol Down: Boot Device Selection Menu
I tried each button on the top row of the keyboard plus: tab, alt, ctrl,fn, windows. In case anyone want to try other stuff.