[SOLVED] Very strange loading PC (x86)

I am running Volumio on a desktop PC (Fujitso Esprimo), i have two 3 TB harddrives,
one contains the system and musicfiles and the other one contains just musicfiles.

I updated to 2.224 via GUI, went ok!

Then I tried to update to 2.254 and the system never came up, from a connected monitor it says that there is
no OS to load.

In order to try something I flashed v 2.201 on a USB stick and tried to load it, setting USB stick as first loading medium in BIOS
and the HD containing volumio as second.

To my suprise it loaded from the HD and the 2.254 is now up and running.

I rmoved the USB stick and made a cold start, nothing happens,
I powered down and reinsterted the USB stick and powered up, it loads from HD and working!

Can anyone explain what´s going on?

Could you please do us a big favour and not post your problem in three different sections :unamused: