HP Workstation boots with 6 beeps and no video following changes in the F10 setup utility.
Symptoms:
After changing and saving one of the following two settings in F10 setup:
1. Security / Secure Boot Configuration / Secure Boot -> Enabled
2. Advanced / Device Options / Video Option ROMS -> EFI
The system may produce 6 beeps on reboot, and will no longer show video on screen or load the operating system. There will appear to be no way to return to the F10 setup menu and change the settings back.