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First time installer of Ubuntu.

I have installed Ubuntu as dual-boot system onto a Sony VIAO Tap 20 running Windows 8.1. When the computer reboots, GRUB2 does not appear: the computer launches directly into Windows 8.1.

You can find boot-repair log here:

http://paste.ubuntu.com/11836136/

This shows that there are 2 volumes which have an /EFI/ubuntu directory: sda1 and sda3. (If I understand correctly, sdb1 is my Live USB stick so it is not relevant here). It also promises that there are two files - /EFI/ubuntu/grubx64.efi and /EFI/ubuntu/shimx64.efi in the sda3 volume, but on inspection from within Ubuntu (booting from a Live USB) I cannot find the /EFI/ubuntu/grubx64.efi file (annotated screenshot).

I would like to discover which of these two volumes is being used on start-up, so that I can set the correct path for the bootmanager.

I have started following the instructions on Gary Newell's Fix the UEFI Bootloader page, but it seems to be failing at the command mountvol g: /s. Here's the output of my session in the Administrator Command Prompt:

C:\WINDOWS\system32> mountvol g: /s
C:\WINDOWS\system32>wmic logicaldisk get caption
Caption
C:
G: 
C:\WINDOWS\system32>cd g:\
C:\WINDOWS\system32>cd g:\EFI
C:\WINDOWS\system32>

This indicates that a volume named G: has been mounted, but it is impossible to move to it or to any directories in it. It would appear that the mountvol /s is only doing part of what is expected.

I understand that this is supposed to "mount the EFI System Partition on the specified drive", but that it works "for Itanium-based computers only" source

When I run the set command in the Command Prompt, it tells me that PROCESSOR_IDENTIFIER=Intel64 Family 6 Model 58 Stepping 9, GenuineIntel. I see no sign of Itanium there (but perhaps I'm not looking for the right data).

Is there a different command that I can use to mount the EFI System Partition on this computer? Or is there a different technique that I can use to ensure that the bootmanager reads the right file and launches Grub?

James Newton
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  • Your sda3 is the ESP - efi system partition. Vendors or Windows often have a recovery partition with boot files and are able to use it, but otherwise it is not used for UEFI. But Sony often will only boot "Windows" as they modify UEFI to use Description. That is not UEFI standard and Ubuntu has a policy statement that that is not to be used by vendors. http://askubuntu.com/questions/486752/dual-boot-win-8-ubuntu-loads-only-win/486789#486789 – oldfred Jul 07 '15 at 21:13

1 Answers1

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The reference to Itanium-based computers is outdated. The first computers to use EFIs were Itaniums, but EFI/UEFI has been used in AMD64/x86-64 computers for several years now. (They became common on new computers in mid-2011. Just about everything to ship with Windows 8 and later uses UEFI.) I'm sure that page, or at least that Itanium comment, dates from the period when only Itanium-based machines used EFIs.

Note that when you mount the ESP via the mountvol command in an Administrator Command Prompt window, the ESP is really only accessible in that same window; you can't get to it via your normal GUI file manager. It's not clear from your question whether you're having problems in the Administrator Command Prompt window or elsewhere. If it's in the Administrator Command Prompt window, then my suspicion is that the filesystem is damaged.

Rod Smith
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  • In that case, it looks as if my question becomes: How do I repair the file system? The boot-repair log was generated after it had performed basic repair. Is it on the Windows side that I need to make the repairs? Does the computer actually know about Windows or Ubuntu at the point when it reads the ESP? – James Newton Jul 07 '15 at 20:43
  • You could try using dosfsck in Ubuntu. Perhaps CHKDSK in Windows would work, too, but I've never tried it on an ESP. When the computer is beginning its boot process, the EFI doesn't know anything about Windows or Ubuntu. (Well, mostly. Some manufacturers encode references to the Windows boot loader filename in their EFIs.) – Rod Smith Jul 07 '15 at 20:52