Ubuntu – How to use windows bootloader to dual boot windows and ubuntu on uefi

Without more information, any answer will be guesswork. I recommend you boot from an emergency Linux disc, run Boot Info Script, and post a link to the RESULTS.txt file that it produces. This will provide information about your partition layout and boot loader configuration.

Contrary to what TheX wrote, Ubuntu most emphatically does support (U)EFI booting. TheX is confusing UEFI with one of its specific features, Secure Boot, which is intended to improve security. Ubuntu has supported (U)EFI for quite a while, and they're working on seamlessly booting on systems with Secure Boot enabled. They may even have incorporated such support in Ubuntu 12.10, but I'm not positive of that.

Edit:

Your system is definitely not booting either OS in EFI mode. Both your hard disks use the MBR partition table, and Windows ties the partition table type to the firmware type, with MBR being superglued to a BIOS-mode boot. You also have no EFI System Partition (ESP) or FAT partition, which are required to boot UEFI-based PCs. Thus, your suspicions about a mixed BIOS-mode/EFI-mode boot are misplaced.

My hunch is that you've accidentally changed a firmware setting -- perhaps you've enabled a "fast boot" option or changed the splash screen. This will affect how the BIOS goes through its initial tests and displays, and could make it harder to access its settings or activate its boot manager. I recommend you go into the BIOS settings and look for such options. I'm not familiar with your specific model so I can't give more specific advice on this score.

Once you've booted Ubuntu, you should be able to get it to detect your Windows configuration and add it to the GRUB menu by doing a grub-mkconfig -o /boot/grub/grub.cfg. If Windows still doesn't appear in the GRUB menu, you may need to create a manual entry for it in /etc/grub.d/40_custom; or you can use your BIOS options to select the boot device, as you've done in the past, if you can slow it down to the point that getting to those options can be done reliably.

After 1 year I came across the same problem again. Luckily this time I found a solution. In order to add an OsLoader in windows Boot-Manager which loads non-Windows UEFI images you need to manually edit BCD registry. In RegEdit there is a key named "HKEY_LOCAL_MACHINE\BCD00000000" - which is loaded from Windows EFI System-Partition and editing it's subkeys directly edit the BSD file. There is a key named "Description" under it but we'll focus on the other one named "Objects". Under it you need to a new object (or modify existing). Then under the target-object-GUID-name you need to edit the "Description" Type value to "0x10100003" (which means firmware application osloader - credits for this find go to this page). That's it - then the 'path' and 'device' elements of this object specify an UEFI file which will be loaded when the OS-Loader is selected.

BIG WARNING:

Don't do the above just to test it - loading an Uefi this way burns it down into the Uefi Boot configuration and after loading - you may wouldn't be able booting to Windows again (unless the app you loaded doesn't reset the Uefi Boot Cfg) - so use this only if you're sure about it.

I did so and then I should manually fix my Windows boot-up using Uefi Boot Cfg. Which is prefered to use.

EDIT: I forgot to add that you first need to own permission for editing "HKEY_LOCAL_MACHINE\BCD00000000", which is easy - just click Properties on it and change permissions ;).

EDIT: This discovery shows that the most powerful (and easy - at least for me) way of editing Windows BSD is using the registry. The behavior I accomplished by doing so - isn't possible to be done using BCDedit, neither the BCD WMI.