I have two Hard disk drives, as shown in the screenshot


First HDD (Sda) is a MBR Disk and second HDD (Sdb) is a GPT Disk (Which has windows 8.1x64). I have installed ubuntu on Sda4 disk and windows 8.1 on Sdb4. I need to setup grub to boot both windows and ubuntu OSes with EFI capable mode (my motherboard is intel DH77KC and it has UEFI bios)

I tried to install grub and search for Windows 8 but it doesn't detect win8, also the windows 8 disk is inaccessible on ubuntu... I have to disable EFI mode so I can boot grub before it automatically boots up windows 8...but without efi mode, win 8 doesn't boot, so I need to install grub on efi support without re-installing ubuntu. is it possible? only windows 8 is on efi mode, windows 7 is mbr mode.


If you really don't want to reinstall Ubuntu, you can try to convert your install into UEFI mode this way. But it may fail as your Ubuntu disk is not GPT.

If it fails, then backup your documents onto an external disk, format your sda disk in GPT, set up your BIOS (UEFI firmware) in UEFI mode, and reinstall Ubuntu on sda.

  • Thanks for answering,I have a question. If I mange to reinstall ubuntu in EFI mode, grub will recognize my EFI-capable windows 8, but will grub recognize my non-efi capable Windows 7 ? – Prasad RD Jan 8 '14 at 6:47
  • It will, but the GRUB menu will not allow you to boot Win7 (the Win7 entry in GRUB will fail). GRUB cannot manage a mix of UEFI and non-UEFI systems. – LovinBuntu Jan 8 '14 at 18:22
  • 1
    You can convert a BIOS-mode Windows to boot in EFI mode as described here. Alternatively, rEFInd can switch boot modes seamlessly; however, it can fail in the case of complex setups and on some computers. In order to work, you must edit refind.conf: Uncomment the scanfor line and ensure that hdbios is among the options. – Rod Smith Jan 11 '14 at 17:56
  • @RodSmith it is helpfull! thank you for commenting :D – Prasad RD Jan 15 '14 at 13:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.