White screen flashes on cold boot after Dell logo and before lock screen.

I can't tell exactly when this started as I have upgraded the NVIDIA drivers as well as the Dell bios and switched from running the onboard Intel HD 630 to GTX 750ti , but now on a cold boot, with the fast startup off, the screen flashes white for a sec after the Dell logo. It could possibly be white noise but I can't focus on it fast enough. It doesn't happen on restarts. I'm connected via hdmi out to a LG TV.

Dell XPS 8910 using the NVidia GTX 750ti and an HDMI TV as monitor Bios version is 1.1.0 ,1.1.0 Original version was 1.0.9, 1.0.9, can I revert back to 1.0.9 ?