I have an AsRock mainboard with UEFI BIOS P1.50 02/14/2014. The firmware "Fast Boot" option is set to "Fast", Boot Option #1 is set to "AHCI P4: OCZ-VERT...": this is BIOS not UEFI boot. This boot disk has an MBR partitioning scheme (# parted -l | grep Partition\ Table:). Therefore Ubuntu 14.04 is installed in BIOS/CMS (Grub-PC) mode. The Ubuntu boot process ends in a text console (no GUI). There is no external graphics card in use. The stock Ubuntu kernel is replaced with Ubuntu supplied mainline 3.16.0-031600rc6-generic.

dmesg outputs lines containing BIOS, like:

  • SMBIOS 2.7 present
  • Calgary: detecting Calgary via BIOS EBDA area
  • Calgary: Unable to locate Rio Grande table in EBDA - bailing!
  • [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored
  • BIOS EDD facility v0.16 2004-Jun-25, 0 devices found

The ASRock BIOS it selves display this help text for "Ultra Fast - Fast Boot":

Ultra Fast mode is only supported by Windows 8 and the VBIOS must support UEFI GOP if you are using an external graphics card. Please notice that Ultra Fast mode will boot so fast that the only way to enter this UEFI Setup Utility is to Clear CMOS or run the Restart to UEFI utility in Windows.


  1. I suspect after changing UEFI setting "Fast Boot" to "Ultra Fast" that the machine will no longer boot into Ubuntu's console.
  2. I expect when first exchanging "Grub-pc" with "Grub-efi", that the machine will still be able to boot to a grub menu (thus allowing to change the "Fast Boot" setting back to "Fast" without clearing CMOS).

Are these two "Fast Boot" assumptions correct, and/or, may I expect Ubuntu 14.04 running mainline kernel 3.16rc6 and Grub-efi to still boot to console after enabling UEFI Ultra Fast Boot?

1 Answer 1


Ultra Fast no longer boots BIOS mode Ubuntu

When changing "Fast Boot" from "Fast" to "Ultra Fast" (BIOS+MBR) indeed Ubuntu does no longer boot in its text console.

Boot enters the ASRock UEFI Setup Utility instead

That is a luck. Now there is no need to clear the CMOS to enter the Setup utility again, just change the "Fast Boot" value and reboot.

Ultra Fast requires EFI/UEFI mode Ubuntu

After converting the existing Ubuntu installation from CMS/BIOS boot into EFI/UEFI boot the same machine is able to boot Ubuntu using Ultra Fast boot mode. Access to UEFI setup utility is no longer possible using F2 or Del key combinations during boot.

  • It's worth noting that the UEFI setup utility should be accessible from the grub menu.
    – jpaugh
    Dec 4, 2020 at 2:34

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