Debian Dual Boot installation GRUB not showing

debiandual-bootgrub2windows

I am trying to install debian-live-8.4.0-amd64-cinnamon-desktop.iso (available from here) to my PC with windows 10 OS.

I did following steps:

  • I put it on USB
  • Booted from USB
  • I had ~105GB of free space which was automatically
    divided between root (/) (~100GB), swap (~5GB) and BIOSBOOT(1MB).
  • I ran Debian installation.
  • GRUB2 (It is v2 I think) installation comes up, and it says something
    about it did not find any other OS and if I want to install grub to
    the MBR. I select yes and then I select SSD with windows installation
    (where Debian was installed as well) /dev/sdb and GRUB seems to be
    installed.

But after reboot, GRUB is not showing. If I go into bios, there is no BIOS boot point for grub, just Windows Boot Manager/DVD-ROM/My nework card/(and USB/UEFI USB in case USB is connected…)

After installation SSD is divided in following order:

  • Recovery Partition (~450MB)
  • EFI System Partition (~100MB)
  • C: NTFS (~366GB)
  • BIOSBOOT (~1MB)
  • Ext4 (~94.59GB)
  • Swap (~4,04GB)

I also had my HDD (/dev/sda) and USB (/dev/sdc) connected during installation
Any ideas what am I doing wrong?

Best Answer

Alright, partially thanks to @Johan Meyreen I think I now understand what happened and I fixed it.

Debian Jessie installation does not support UEFI boot option, and since my PC ran on UEFI, grub boot option was simply not installed.

I booted into Debian via rEFInd Boot Manager tool and then followed this simple guide to install grub into EFI partition.

Now debian boot option is available in bios and grub seems to be working.

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