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I have a Toshiba Satellite L855-S5372, which came pre-installed with Windows 8. I succeeded to install Ubuntu 12.04 on it (intending to dual-boot), but the UEFI refused to recognize it and went to Windows every time. I found a very hackish work-around: every time I want Linux, I go into F2 Setup at startup and disable Secure Boot.

Recently, after an upgrade on the Windows side, this method has stopped working, it goes to Windows every time regardless of secure boot option. I have spent an hour with the setup to no avail. How can I boot Linux, and how can I continue to dual-boot Windows and Ubuntu?

rvighne
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  • I suspect the windows upgrade has overwritten the grub bootloader that allows Ubuntu to boot. You will need to manually reinstall grub. See http://howtoubuntu.org/how-to-repair-restore-reinstall-grub-2-with-a-ubuntu-live-cd for instructions –  Mar 23 '14 at 05:21

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It's possible that the Boot Repair utility will fix this problem; however, it's important that you boot this tool in EFI mode. (Running it from a live CD is fine.) Booting it in BIOS/CSM/legacy mode is likely to either not work or create a very hackish fix that might create more problems than it solves. To ensure that you've booted in EFI mode, open a Terminal window and look for the directory called /sys/firmware/efi. If it's present, you've booted in EFI mode; if it's absent, you either haven't booted in this way or you're using a distribution that's configured strangely.

FWIW, recent versions of Ubuntu do support Secure Boot, at least well enough to get GRUB booting with Secure Boot active. I can't be positive, but my suspicion is that you actually installed Ubuntu in BIOS/CSM/legacy mode and were switching between that mode and EFI/UEFI mode. If the Boot Repair fix I've suggested works, then you should end up booting both OSes in EFI/UEFI mode, with GRUB to switch between them.

Another option is to disable Secure Boot but ensure that your firmware is booting in EFI/UEFI mode. (How to do this depends on your firmware's user interface, so I can't provide specific instructions.) If an EFI-mode version of GRUB is installed, you should then be able to select it from a boot menu and run it; or you can install another boot loader or boot manager. Installing my rEFInd from Windows, along with an EFI filesystem driver for whatever filesystem holds your Linux kernel, should work pretty well. Using this option with Secure Boot enabled is also possible, but requires extra configuration.

Rod Smith
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  • Thanks for the response. I believe I installed Ubuntu in UEFI mode. How can I tell if I'm in EFI mode from the livecd? – rvighne Mar 24 '14 at 02:03
  • Check the second half of the first paragraph of my response; the answer to your question is there. – Rod Smith Mar 24 '14 at 12:47