Have several Optiplex 7040's that will not apply the BIOS updates. Most are on version 1.2.8. I've tried from both USB and from Windows 10. It loads the file, powers off, powers on. I get a video signal with a blank screen for several seconds. Then the machines power off and on again. At this point I have the Dell logo, but the the bios is not updated. 

I don't see any pre-req's for stepping up bios versions in order to apply the latest version 1.24.0. 

Any help will be much appreciated.