Hi,

F12 is a One-Time Boot menu. you can see all the supported boot options which the System has currently . This is mainly for the one time boot mode entry. when you restart the system the system will boot only from by the priority which you specified in the F2 screen settings under -->General --> Boot Sequence.

F2 screen Boot sequence is for setting the priority on which the system should boot at startup.( without using F12 each time ) 

F2 boot sequence ( Pre- Set boot priorities ) is different from F12 boot ( One time Boot Menus ) .

For more clarification: - Insert USB into system and see in F12 boot. you can see USB boot option.  

                              - Remove the USB from the system and see in F12 boot. you will not find the USB boot option.( inspite of this Option is disabled in F2 or not. ) 

Hi,

thanks for your answer.

You say F12 shows all the boot options, the system has. But for legacy mode, it's working for me. I press F12, select the options I want to have, save, boot, F12, and under Legacy, there are exactly the checked options.

For UEFI, the system doesn't care, which options I check or uncheck, it always shows me usb or cd (when usb or cd is plugged in).

What I want to do is, to prevent, that our users can boot from their own usb stick or cd.

Is there a way to realize this?

Hi ,

Try this. these are the options to disable the boot support of USB and CD devices. 

Bios Version:  A12 .

System Configuration >> USB configuration >> uncheck Enable Boot Support - ( this will disable USB boot support )

System Configuration >> Miscellaneous Devices >> uncheck Enable Module Bay - ( this will disable the CD/DVD device boot support )

Now press F12 and check.  USB and DVD/CD boot devices will not be shown even if Devices are connected. 

Note:- i hope this options will be available in A13 Bios under same category. 

HI,

Better late then never ;)

I fixed the problem by installing the latest BIOS version. Now I can setup all the boot methods I want.

Thx a lot.

Hi,

I have the same question for other dell systems: I just bought an XPS 13 after my macbook has been stolen.

I then discovered that apple's firmware had a cool protection against booting from external devices: you can still boot normally from the hard disk, but a password is required to boot from a usb key/cd rom.

This would be especially nice since lojack is completely useless at least with linux (and my xps 13 came with ubuntu pre-installed).

Thanks,

uefi boot khong xoa