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I bought a new dell laptop a couple of months ago that's running Windows 10. I did not install a password. I had heard about the secure boot and disabled it through the UEFI (F12 on startup).

I wanted an app (Microsoft now has an app store) but they make you get a Microsoft account. A few days later I shut down the machine and upon restart, it asked me for a password.

I knew that I could get into the machine and see the files (my passwords are in a text file on my windows desktop) if I installed Ubuntu.

I tried to see the files from the "Try Ubuntu" but they weren't accessible, so I made a small partition and installed Ubuntu. That's when I first heard about fast boot. Ubuntu installed OK. I have the grub menu that shows both Ubuntu and Win 10.

When I try to boot to Windows 10 I get a pixelated screen and it will not boot. I also can't access UEFI by hitting F12. My guess is I needed to disable the fast boot in Windows before I installed Ubuntu, but it's too late now.

Is there a way I can turn off grub or disable that feature from within Ubuntu?

I can't access the UEFI to get to the boot menu and it's stuck on booting from the HDD so I can't boot from a CD or USB.

I only need to get into Windows one time to turn off the hibernation/fast boot but can't find a way.

Any help you can give will be greatly appreciated!

pa4080
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user639787
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1 Answers1

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Sometimes EFI boot settings get damaged, making it difficult or impossible to boot into the firmware setup utility (what you're calling "the UEFI"). This can create a chicken-and-egg sort of situation, since the solution to such a problem is to reset all the firmware settings to the default, but you have to access the firmware setup utility to do this. I can think of several possible workarounds:

  • You could try putting my rEFInd boot manager on a USB flash drive or CD-R and boot to it. On most EFIs, rEFInd shows an option on the second row of icons to reboot into the firmware setup utility. Select this, reset the options to their defaults, use rEFInd again to reboot to Ubuntu, and re-install GRUB (sudo grub-install) to get things working again. If you can't get rEFInd to boot from the USB drive, you could install it to your hard disk, but that runs the risk of further corrupting the firmware settings.
  • GRUB includes an ability similar to rEFInd's, but it's often not active. I don't know offhand what an entry to do this looks like, but if it's not present in your GRUB menu, you could try to track this down and create such an entry. You'd then be able to use your existing GRUB to get into the firmware setup utility, much as you'd use rEFInd, then reset its options to their defaults.
  • You could turn off the computer, unplug all your hard disks, and start the computer. With no disks, the computer should launch its firmware setup utility. You can then reset the options to their defaults, plug the disks back in, and restart. The machine might not boot, though, or it might boot to Windows. If the latter, you could use EasyUEFI to create a new entry for GRUB/Ubuntu (its boot loader is EFI\ubuntu\shimx64.efi or EFI\ubuntu\grubx64.efi; the former supports Secure Boot, the latter doesn't). In either case, you could use rEFInd to boot into Ubuntu on a one-time basis or use Boot Repair to fix GRUB.

There may be other ways to do this, too. Using efibootmgr in Ubuntu to delete redundant entries might fix the problem, for instance. (Type sudo efibootmgr or sudo efibootmgr -v to see existing entries, then delete unwanted entries with sudo efibootmgr -b #### -B, where #### is the hexadecimal number of the boot entry you want to delete.)

Rod Smith
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