BIOS lost after Windows 10 Upgrade

What a bad surprise! Having done my upgrade to Windows 10 on my Fujitsu H910 Notebook, no more F1, F2 or F12 options are available any more. Found this now when trying to boot from an external USB disk.

After some investigation it turns out, that Windows 10 by default enables the so called “Fast Start” option, which promises to speed up the system boot by using hibernation technique during the shutdown.

After disabling this feature, the F12 option was available again to select boot devices. It can be done by Settings > System > Power & Sleep. Here, at the bottom under “Related Settings” click on “Additional power settings” which opens a dialog.

Here, on the left, click on “Choose, what the power buttons do” and scroll down to section “Shutdown settings”. Here, uncheck “Turn on fast startup” option, which is on by default.

And I even have the feeling, that my notebook even seems to be faster at startup without that option.