my pc is an ASUS RoG g750jx with dual boot : Debian Jessie and windows 8.1 , until yesterday everything was fine. Yesterday booting my pc it didn't display GRUB and directly booted to Windows,i thought : "not bad i just have to reinstall GRUB". I wanted to boot from usb (it works on others computers) using a Debian-live ,as soon as pc boot i press ESC key to get the boot override menu' , from the list i select the usb device after few istants it send me to BIOS. it happens with every usb i tried (i tried all the ports). Until yesterday i was able to boot from usb without problems ,since my GRUB is magically disappeared i can't boot no more . Seems like some sort of error during usb boot that sends me to BIOS.

Bios settings :

secure boot : disabled Legacy : disabled Usb support : enabled

I didn't change any settings and before yester with the same configuration i was able to boot from USB device!

1 Answer 1


In BIOS-> security, your USB interface could be set to "lock".

  • BIOS -> security USB is set on "Unlock"
    – HaZe
    Nov 21, 2014 at 10:54
  • Can you update the BIOS from the BIOS using USB? Does USB work in windows?
    – Billy_Bob
    Nov 21, 2014 at 22:41
  • yes and i've alredy update the BIOS . Yes USB works in Windows . Can be an UEFI problem?
    – HaZe
    Nov 22, 2014 at 13:58
  • Is CSM enabled? Secure boot disabled and enable CSM (sometimes Launch CSM)
    – Billy_Bob
    Nov 22, 2014 at 14:17
  • CSM is disabled cause i was able to boot without any problem since 2 days ago :( . Yes , secure boot is disabled. Now i remeber that Windows 8 did an update could be that ruined uefi ?
    – HaZe
    Nov 22, 2014 at 14:28

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