help Z170 M5 GAMING stuck on reboot because of bios update

I updatet my BIOS from 1.0 to 1.2 using m.flash and now my pc is not booting, but starts for 1 sec then reboots.
I tried flushing my bios by removing the battery but it didnt help.
a red led at the botom is on, but i cant find info on what that means i...