No Video after Bios update

Hey 

I buyed a Lattepanda V1 and an original 10" IPS Display.

I followed exactly the Totourial for the bios Update and it worked fine. But after Rebooting, there was no signal neither on HDMI nor on eDP (for the 10" IPS ) 

I tried to Hard Reset with the Reset and start Button method. -> didn't work

I tried the F3, enter, F4, enter method -> also didnt work 

The Red LED light up -> if i hold the start button 3 seconds it goes out -> if i press the start button again it lght up again.

It feels like the Lattepanda starts up and maybe works but only the display output don't work.

It is an Lattepanda V1 4G/64G with CR200-CC55F 

I hope Someone Can Help me 

PS: Sorry for my bad english